CO THE ARUP JOURNAL in t m

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APRIL 1979

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• Vol. 14 No. 1 April 1979 Contents Published by Movement towards axcavatton - » Movement towards excavation » Ove Arup Partnership 0 4 8 12 16 20 24mm THEARUP 13 Fitzroy Street. London. W1 P 6BQ 0 4 8 12 16 20 24 28rt

Editor: Peter Hoggett Art Editor: Desmond Wyeth FSIAD Editorial Assistant: David Brown JOURNAL \s«*»o~2\\\^ stage St. John's College 2 Sir Thomas White Building, by Philip Dowson

Value for money 15 in urban renewal, by Peter Dunican

i // Arts and Social Sciences 20 Computed Wall Movements South Wall movements FINAL STAGE Building, Trinity College, Dublin, (measured) by Peter Ryalls Fig. 12 Fig. 13 Fig. 14 The British Library: 26 New Palace Yard: New Palace Yard: New Palace Yard: a computer model south wall movements computed south wall movements measured final movements computed and measured for London clay, by David Croft, Brian Simpson, and Nick O'Riordan Figs. 12-15 show the comparisons between the measured and computed values for the —•———' deflections of the diaphragm walls and the pore pressures. These results are discussed in detail in Reference 2. The paper also contains a comparison of the site measurements at Neasden Underpass as described by Sillser al" with the results of back-analyses. While the New Palace Yard excavation is best modelled Front cover: Sketch of St. John's by an axisymmetric analysis, Neasden in Back cover: Roof plan of St. John's contrast is nearer to the plane strain case. Model LC gives good correlation in both cases. St. John's was the subject of a limited com• sponse to their review, rethink the problem St. John's College petition, held in 1966, between ACP, Howell from scratch. We gave each other six months. Killick and Partridge, William Whitfield, and The present, more modest design, was the Sir Thomas White ourselves. The brief originally included, on a outcome. The new buildings have 156 sets larger site, a lecture theatre, a science library, and bed-sitting rooms. This effectively Building a swimming pool, married Fellows' flats, a doubled the existing accommodation within special dining room for the governing body, a the college precincts. DESIGNED BY restaurant for the undergraduates, and parking The design of the rooms themselves includes ARUP ASSOCIATES for 170 cars. Both sides of Museum Road were a wide range of size, shape and character. The included within the site. organization of the plan into'staircase-service- Philip Dowson Pore pressures hN/m2 The design for this first scheme was worked links' and pavilions provides for adaptability 220 0 Pore pressure measured at this position Fig. 15 'A world within a world', in the words of the up and presented in 1969. At this point there within the latter to accommodate Fellows' on completion of excavation President of St. John's, or 'a room of one's was a new President, and a developing recog• flats. All new development is now to the New Palace Yard: own', in those of the Principal of Somerville, nition that the initial brief was no longer south of Museum Road, and so within the pore pressures computed and measured sum up the aims behind the design of an wholly relevant. There was a need for a review. natural college precinct. undergraduate room. Rather than tinker with the existing proposals, The combination of the scale of this scheme Conclusions References Geomechanics, Melbourne, 1971 and St. John's new building in Oxford, which was we suggested that the College should re• and the complexity of its brief, with the ex• published in the Proceedings, /, pp. completed last year, combines in many assess its needs in the light of the work that treme vulnerability of its site, presented the The geotechnical problems associated with (1) CROFT, D. D. and RYALLS, P. J. The 180-189. respects a developing set of ideas that can had been done. In the meantime, we would most difficult architectural problem we have the design and analysis of the basement re• British Library. The Arup Journal 13 (4), be traced from our first university commission also go away, lick our wounds, and, in re• ever had to undertake. taining walls have been described. A non• pp 2-6, 1978. (8) MARSLAND, A. Clays subjected to insitu plate tests. Ground Engineering, in 1957 for a graduate building for Somerville linear elastic-plastic model for London Clay, (2) SIMPSON, B., O'RIORDAN, N. J. and 5 (6), pp. 24-26, 29-31, 1972. College. These ideas were developed in a which has been developed, is described and CROFT, D. D.: A computer model for design for some flats for Bracknell New Town, the results of predictions made using this the behaviour of London Clay. Paper (9) ATKINSON, J. H. The deformation of and through later buildings for Corpus Christi model have been compared with measured to be published in Geotechnique June undisturbed London Clay. PhD Thesis, and Trinity Hall Colleges in Cambridge, and values obtained from laboratory and field tests 1979. University of London, 1973. for a further scheme for Somerville. and from instrumented excavations. (3) BUR LAND, J. B. antf HAN COCK, R. J. R. (10) LEWIN, P. I. Stress deformation charac• In the case of St. John's, we had to inject a Model LC is currently being used in the Underground car park at the House of teristics of a saturated soil. MSc Thesis, large new development into one of our his• analyses of the deep basement construction of Commons, London: geotechnical as• University of London, 1970. toric precincts, and whilst it had to fulfil the British Library. At the time of writing this V pects. The Structural Engineer, 55 (2), (11) SOM, N. N. The effect of stress path on today's needs, it had to do so within a very article the base analysis has been completed % .r pp. 87-100, 1977. the deformation and consolidation of sensitive historic context. It is a modern and work is continuing on the various para• London Clay. PhD Thesis, University building, but intends to reflect the mood of -1 metric studies that are required in order to (4) COLE, K. W. and BURLAND, J. B. of London, 1968. Oxford, the character of its surroundings, and assess the sensitivity of the results to the Observations of retaining wall move• to settle into the established pattern of this values of the input data. When these have ments associated with a large excava• (12) PECK, R. B. Deep excavations and medieval city. been completed then appropriate values for tion. Proceedings of the 5th European tunnelling in soft ground. State of Art the final design of the diaphragm walls will be Conference on Soil Mechanics and Report, Proceedings of the 7th Con• Diverse relationships available. It is intended that future articles will Foundation Engineering, Madrid, 1972. ference on Soil Mechanics and Foun• Common to all these buildings, however, is a describe this analysis and will contain pre• Vol. 1. dation Engineering, pp. 225-290. 1969. dicted values for deformations that will be wish to create rooms with a sense of location (5) ST. JOHN, H. D. Field and theoretical (13) SCHOFIELD, A. H. & WROTH, C. P. compared with the values measured during and of generosity, a sense of enclosure and studies of the behaviour of ground Critical state soil mechanics, McGraw- construction. release. A wish to develop a relationship be• around deep excavations in London Hill, 1968. tween the small scale and the large, and be• Clay. PhD Thesis, University of Cam• (14) MAY, J. Heave on a deep basement in tween the manmade and the natural via the bridge. 1975. Credits the London Clay. Conference on Settle• intermediate spaces created between the in• (6) BUTLER, F. G. Heavily over-consoli• ment of Structures, Cambridge. 1974. terior and the exterior areas within these Client: dated clays. Review Paper. Session III of schemes. We aimed to exploit the richness The Department of the Environment (15) SILLS, G. C, BURLAND, J. B. and Conference on Settlement of Structures, and unity that can at once be derived from the Architect: CZECHOWSKI, M. K. Behaviour of an Cambridge. 1974. diverse use of repetitive elements, and the Colin St. John Wilson and Partners anchored diaphragm wall in stiff clay. various strands that can be woven within Services Engineer: (7) MARSLAND, A. Large in situ tests to Proceedings of the 9th International strict disciplines, which can help to identify Fig. 1 Steensen, Varming, Mulcahy and Partners measure the properties of stiff fissured Conference on Soil Mechanics and the 'part' within the 'whole', and so help to Model of the winning scheme - subsequently abandoned Quantity Surveyor: clays. Paper presented at the First Aus• Foundation Engineering, 2, pp. 147-155, create a sense of belonging. Davis, Belfield and Everest tralian-New Zealand Conference on Tokyo 1977. 31 Comparison with laboratory and field ditions. Up to about 2% vertical strain the The results of the comparison with the plate- tests computations agreed well with measurements. bearing tests reported by Marsland are shown However, no failure was predicted and the in Fig. 9. The measured load/displacement Predictions of the model have been compared shear stress increases slowly. This occurs curve is compared with predictions made •0 i NORTH with the results of plane strain and triaxial because the model is not designed to cope using three different values for the radius of undrained tests carried out by Atkinson. In with situations of significant strain in the the kinematic yield surface (ea). The com• Fig. 6 the computed predictions for two un• circumferential direction. puted load/deflection curve is close to that drained plane strain tests are compared with In Fig. 8 the results of a large number of measured at stresses up to about 80% of Atkinson's results, and a good correlation is oedometer tests have been plotted to a norma• failure stress. Rather better results could be achieved in each case. sinngloorr bedroom lized scale. The results are taken from the achieved using a higher value of Ea= 500 ue, Q I DINING The triaxial test is much more difficult to British Library site investigation and predic• rather than 200 ue. tions from Model LC have been superimposed LOWER COURT model. Two approaches have been tried and Comparison with measured heave onto these plots. In studying these results it is A ] the results are shown in Fig. 7. If plane stress below a deep basement • -T A necessary to compare the gradients of the is assumed, the results agree fairly well with 1 curves in the various ranges of stress. On this May * published measurements of the heave Atkinson's measurements. The failure stress is coFlfege \\ of a basement built over a deep layer of 0 lower and occurs at smaller strain than that basis it can be seen that the computed and t measured results agree fairly well in the stress London Clay. The net unloading after excava• measured, possibly because there is less re• 2 2 tion and construction was about 175 kN/m . MCR COURT striction in the third principal direction than range of major interest, 100 to 400 kN/m . In HAW Unfortunately measurements were not started general, the stiffness of the model is greater <' occurs in the laboratory test. A single finite nd 'V until the end of construction and a complicated 2 FLOOR 3'" FLOOR S ^ element was also tested in axisymmetric con• than that of the soil being tested. • extrapolation is therefore needed to estimate ~ • the total heave which has taken place. The ' more recent readings suggest that about 130 Fig. 2a above mm of heave has occurred in 10 years and Typical layout of 'set' with bedrooms on GARDEN J L that there is no indication that the movement intermediate floor is approaching a limit. A simple program using Model LC was written Fig. 2b to provide a prediction for this problem. The Model of 'set' stair to bedroom final heave was computed to be 228 mm, T v. assuming that the pore water pressure will ft eventually return to its original value. How• t> VI ever, the predictions are extremely sensitive 6 ITofrER COURT £ r Key plan to the pore water pressure distribution, SECTION A A particularly in the upper layers and this Fig. 3 right value reduces to 180 mm even if only a small First scheme: general section and site plan reduction in water pressure is assumed. It would seem that in this case the model will Proposed cat park give a reasonable prediction, although pos• sibly somewhat on the high side. This may be East - west section i i.iii ,i clay contrasted with the tendency to predict too little deformation in the laboratory tests. Back-analyses of excavations in London Clay The excavation for the car park at New Palace Yard has been back-analyzed as part of the calibration procedure for Model LC. Burland I • a and Hancock3 describe the site, together with Undrifground railway the design, construction method and moni• toring of the New Palace Yard excavation. North - south section Figs. 10 and 11 are reproduced from their paper and show a plan and section of the work. St. John* provides further information on the Fig. 10 Fig. 11 (below) excavation process and its effect on the New Palace Yard: general layout New Palace Yard: plan and sections ground.

Original ground ravat 104 Fig. 4 Fig. 5 Final scheme: model of development shown within the context Aerial view of site of existing buildings

ip. iik ilk iik ifk 4tk rri IT*

East-west section North - south section-HH

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66M, Fig. 6a left Fig. 6b MM Facade to 'sets' Facade to bedsitting rooms Vertical compress.on ",.

Typical vertical stress Ovsti/m'

(a) SWELLING FOLLOWED BY CONSOLIDATION

Normalized Stress <5v/0»'|ma»

1 ~ —— Measured

L—J Compulse!

"J »0

1 2 3 Typical vertical suees Ov'hN/m'

Horizontal compression % b) CONSOLIDATION FOLLOWED BY SWELLING. Four faces porter's lodge off the Lamb and Flag Pas• Fig. 7 There are four faces to the design of St. sage, and this facade also forms the outer The urban 'face,' as glimpsed from St. Giles John's. The first is glimpsed from St. Giles', wall of the College. There is in a sense also Fig. 6 Fig. 8 and forms a part of the urban scene. The the fifth face - the roofscape and silhouette, Plane strain tests Oedometer tests second appears above the walls of St. John's which had to respect the skyline of Oxford. great 18th century garden, and is seen be• In this case, the organization of the plan tween groups of large trees, as well as from a naturally creates a strongly differentiated set Fig. 8 distance across its open lawns. The third is of forms at roof level, which aim to be com• As seen from St. John's great garden; the elevation to the new quadrangle itself, patible with their collegiate and domestic note that the lowered quadrangle reduces / and finally, there is the new entrance and neighbours. the apparent height /

/ / / 1500 / 3 / VeHical

50 /

1OO0 /

sot.

30 / /

Radia VXI 20 Honzonra 1" stress I Ct'Cumtef ent ial

LL) 10 .wtlemant o

Vertical strain [, % Diam«te*

Measured Pla Radius Ol KYS Computed »iiiwmm«(iic E>21f P»I Computed plane stress •°c: 125 1 too ut

AaiaFmmatfic C, 24 pei 200 »E 11 5O0 u£ giving •36

154E.

Fig. 7 Fig. 9 Triaxial tests Plate bearing tests (b) 1 u /1000 /500

0 8 0

0 6 _

o Pravtoua atatea /E/C = 300 u U • Currant state % Kmamatic ynWd I rises I ridui C„ )

0 4 o //// Id Idl

0 2 ' //// /

n 0-5 10 t-S Settlement/plate diameter (O/B)% A* a* X .¥ •'• componwitt of atrain I 0 5 Shear Strain^ I -E ^ -StiftitefM ina.rJa KYS

Note Values of C were obtained from the plate tests and E <( - Stirfnaas ouUffd* KYS are probabiy about 30% lower than laboratory values

Assumptions qu = 10 C (includes allowance for depth]

E = g'j B(1-VJ) V. 0 4

Fig. 2 Fig. 4 Results of 865 mm diameter plate-bearing The kinematic yield surface effect tests on London Clay; after Marsland (1 971)

Fig. 9 above

'Face' to the new quadrangle

Fig. 10 left 1 \ jnioading Reloading The outer 'face' and outer wall to th college, next to the new entrance Fig. 12 right

4 e 8 The silhouette - the fifth 'face'

Plastic shear strain yt %

7 sK { s sin 4 • c COB • ) (rr, •

2 («r,-»',l 2 Si-tM' *ti*m carton'* to. • mturtiuxi wall d'«pt»C»m«nt 0 2 O* •• Haior and minor principal stfectivs stresses •>•

I 2 5% Fig. 11 below Fig. 3 Fig. 5 View from President's garden with Strain contours around an excavation The state boundary curve new screen wall and summer house

Intermediate range Implementation into elastic/intermediate state and the plastic The parameters of anisotropic elasticity are the finite element stage. adopted. program Fully drained behaviour can be modelled by holding pore pressure constant. The un- E' = E'v (s + c' cot

2 c' = 20 kN/m The program is suited to geotechnical prob• compressibility of the pore water. The bulk Adjacent to the site, to the north, is a small

which gave the old city its uniquely beautiful " ?! hi HI 'I I1C state if that state ismaintainedfor a long period it: io; ?I • (I 40 150 160 ' It colour. Many of the older buildings have now i I I of time. This could model the threshold effects been refaced with Clipshan because the after time lapses, reported by Som. quarry ran out, and the weathering properties \ The work of St. John (Fig. 1) suggests that of Headington were sadly less durable than Vertical msil the ratio of horizontal to vertical stiffness may la sit those of the stones which are now replacing " OS be similar at very small strains to that found

it. We wanted as close a match to the original Hor izonta si ti. in laboratory tests at larger strains. All the stone as possible. Clipshan is too yellow, and IPSIS stiffnesses used for the small strain range have Portland too white, and neither have the subtle ' 10 • been assumed to be proportional to those warmth of Headington. A quarry near Paris obtained from laboratory test results (i.e. provided the nearest that we could find. It the stiffnesses during 'intermediate' behavi• had been used on Chichester Cathedral, and Fig. 15 below our). had many of the qualities of Caen stone. Sur• 015 • Precast 'H' frame prisingly, in spite of transport, the costs were Intermediate strains (outside the KYS) more favourable than for an equivalent Eng• The strains during 'intermediate' behaviour lish stone, largely due to highly mechanized i ... represent the range normally measured in quarrying techniques. laboratory tests. Atkinson* reported that The precast concrete 'H' and half 'H' frames London Clay behaved like an anisotropic were tooled and used a Baladon aggregate elastic material in this range of strain, except 0 ?'. similar to our previous college buildings. The that strains were not necessarily recoverable. attic storey and roof was clad in lead. The Thus the behaviour has the appearance of problem of weathering was very carefully elasticity but is to some extent plastic - hence considered in the design, particularly in view » 030 the term 'intermediate'. of a proposed lifespan of 400 years. The stiffness moduli adopted have been chosen to fit Atkinson's data with the assump• Scale tion that all intermediate stiffnesses are pro• As well as four faces, there are four scales to £ 035 portional to (s + e'eotep') (that is, the mean St. John's. The major one is the organization normal stress in the plane of deformation, of the plan into 'pavilions' and link towers. with an additional term to take account of This arrangement allows flexibility in section cohesion). This assumption ensures that both as well as in plan. Thus in section the terminal Fig. 14 left stiffness and strength are compatible as block is six feet lower than the porter's lodge Stone and wood: typical detail limiting conditions are reached. and the angle between the two wings is L oca no Type ol Test S. u.i e adjusted to suit the site. 0 45 s t Back analysis ol COBS and Plastic strains (approaching the limiting shear In this way, almost one storey in height is lost, Bnttanic House ground movement Builanc! (1972J strength) and, as seen from over the old wall, is of com• New Palace Yard I St Joh parable height to the Canterbury quadrangle 'MCA -Tin. I 119751 It has been found that the curve shown in Hyde Park which faces the main garden. End and corner 0 SO Settlement Record? Hooper (19741 Fig. 5 can be used as a 'state boundary curve': Commercial Unton Fig. 16 below pavilions are square, cheating the eye to be• 19/? that is a curve separating attainable stress/ Chelsea Pl.rte res'. Marsland '1971ai Site plan with ground floor lieve that the others, which are larger, are the strain states from those that cannot be attained. Hendon 1..., Mars,and '1971b same size. This visual deceit makes the build• This curve takes the form of the normalized '. ss ing look smaller than in fact it is. shear stress F plotted against 'total plastic

shear strain' yp:ie the sum of all incremental plastic shear strains, irrespective of direction. If a flow rule is assumed, it can be shown that Fig. 1 this is uniquely related to the plastic volu•

Variation of E (undrained) with mean effective stress; after St. John (1975) metric strain vp. Thus Vp is a reasonable direc• tionless parameter which with suitable mani• pulation and choice of origin, can be related to the voids ratio. 1000). As shear strains increase beyond 0.5%, It has also been demonstrated that the stiff• A modified form of the Cam-clay flow rule however, the secant modulus approaches ness of most soils increases with the mean (Schofield and Wroth") has been found to fit that measured in the laboratory. effective stress: this feature is included in Atkinson's data when used in conjunction with The shear strains occurring behind a retaining Model LC. the state curve as follows:

wall are shown in Fig. 3. For a movement of Svp 0.2% of the wall height (an upper bound for Description of the model = sintp' (F„ - F)

retaining walls in firm soil according to Syp 2 Model LC relates increments of effective Peck' ),the shear strain in the ground exceeds stress to increments of strain, given the current where F = t/(s sintp' + e'eos

The principal axes of plastic strain increment (Ex + £y, EX - Ev. rXV). (e« + Sy. ex - e¥, fxy) space. Its radius = e

Further London Transport and British Rail which is equivalent to the active pressure. Eu/Cu is found in laboratory triaxial tests to be tunnels run just outside the site boundaries The reduction in horizontal pressure (total about 100, but in the field to be between 500 at shallow depth. stress) in the soil outside the wall and the and 10006. Marsland78 has claimed that In this article, the problems associated with corresponding horizontal expansion of the stiffnesses measured in large (865 mm) diame• the design and analysis of the deep basements clay causes a reduction in the pore water ter plate bearing tests are fairly close to the are discussed. The size of these basements is pressure which can become a suction (nega• back-figured values. In Fig. 1 the comparison tive pore water pressure). between triaxial, plate test and large scale such that their design will involve a substan• 5 tial extrapolation beyond the experience This drop in pressure will cause water to flow results is shown, reproduced from St. John . gained from other previous excavations and into the area from other areas where the water It is commonly stated that the reasons for the much lower stiffnesses measured in the labo• it is therefore considered that the best com• pressure is higher. The rate of flow will depend Fig. 17 above Fig. 18 ratory are sample disturbance (especially the putational methods available should be used on the permeability of the clay which is pri• New quadrangle with lowered garden, whose wall First floor plan. 'Sets' are planned on the sou opening of fissures) and bedding of the in the justification of the design. To this end a marily determined by the presence of connec• provides a visual base for the old building bedsitting rooms on the east and north special finite element model for London Clay ting sand lenses and open fissures. The situa• samples in the test apparatus. However, the results of very careful laboratory work show has been developed and will be used in the tion where the change in pressure occurs that remarkably consistent and repeatable analysis. In order to subject the theory to rapidly compared to the rate at which water results can be obtained. Atkinson* prepared criticism from across the civil engineering can flow in is called the 'undrained' condition. 2 triaxial specimens from block samplesobtained profession, a paper describing this model has The increase in water pressure after the struc• at the Barbican site. He found that for strains been prepared and submitted for publication. ture is complete will cause increased com• up to about 1% the material behaviour This article contains an abbreviated descrip• pression and shortening in the basement floor appeared to be anisotropic elastic for a large tion of the model itself and the methods used slabs and inward movement of the wall. variety of stress paths. For a given initial stress to calibrate it. The floor slabs shorten elastically as the com• state, the behaviour was linear up to 1 % shear pression in them increases. In addition, long- strain. Design of the retaining walls term shrinkage and creep will allow further In order to limit ground movements, it is pro• inward movement of the wall to take place. In contrast to the consistency found by posed to construct the basements by a It is apparent from the above description that Atkinson, it would be expected that the effects scheme similar to that used for the New the deformation of the soil and structure and of sample disturbance and bedding would be Palace Yard Underground Car Park3. Dia• the stresses induced in them will be highly fairly random. It therefore seems appropriate phragm walls will be constructed around the indeterminate and will depend on the con• to investigate other reasons for the consis• site boundaries and these will be supported struction sequence and timing and also on tently low stiffnesses measured in the labora• by floor slabs. Excavation will proceed by therelative stiffnessesof thedifferent materials. tory. mining beneath successive floor slabs. The In order to design the diaphragm walls and to Many workers, including Lewin'0, Som" and slabs will be supported by piles and columns predict the likely movements of the tunnels Atkinson have reported 'threshold effects' in placed before excavation is started. and surrounding buildings, it is necessary to London Clay and other soils. In some of his Generally soil-retaining structures can be de• understand not only the deformation be• oedometer tests, Som held samples at constant signed using the standard Rankine or wedge haviour of the structure, but also of the London stress for many days and then recorded excep• methods. These, however, assume that the Clay and of the underlying strata. A number of tionally high stiffness as the next small incre• limiting active and/or passive states are approximate Young's Moduli for these are ment of strain was applied. Lewin reported a attained and give no information on the im• available from various back-analyses of deep similar high stiffness when the direction of plied strains and movements. To decide excavations in London Clay (Cole and Bur- straining was changed. It is therefore useful 5 whether such approaches are valid in this land* and St. John ),and these can be used in to compare the magnitudes of strains relating case it is worthwhile to consider the sequence finite element and other computations. How• to various loading situations as follows: of events that will occur in the soil/structure ever, these previous back-analyses have The stiffness parameters reported in laboratory system during and after the construction of assumed linear elastic soil behaviour and, tests are usually based on a range of shear the deep basements as follows: although a fair degree of agreement with field strain up to about 1%. Atkinson states that The construction of the diaphragm wall will measurements has been obtained, a number his measurements at strains of less than 0.2% reduce the magnitude of the horizontal stres• of problems have been noted as follows: are not reliable and therefore quotes Young's ses in the clay causing inward movement of It has been difficult to achieve good pre• Moduli based on tangent moduli at 0.25% the surrounding soil. However, as the wall is dictions of both the movements of diaphragm strain. walls and of points outside the excavation constructed in short lengths, the effects will In Fig. 2, the results of 'typical' plate bearing from the same analysis. be localized and the overall reduction in tests reported by Marsland are reproduced. pressure will probably not be great. In order to obtain satisfactory results, the An approximate scale for the average shear The bored piling operation will result in in• stiffnesses assumed for the London Clay have strains occurring within one diameter beneath ward movement of the clay in each pile shaft. to be very much greater than those measured the plate has been added to the horizontal These movements will be associated with in laboratory tests. axis. At very small strains (<0.1%), the tan• overall inward movements of the diaphragm gent modulus is similar in magnitude to the 26 wall and surface settlement within the site. It is apparent that the material inside the dia• values found from back-analysis (Eu/Cu = Second scale traverse the coffered ceiling of the upper level, (Fig. 20). The second scale is the structural one. The Fig. 16 precast 'H' frames define the enclosed spaces The entrance hall, The exhibition hall, (Fig. 21) is of double within the pavilions. using air conditioning storey height. Demountable exhibition walls ducts as sculpture shown at the left of the illustration are Third scale Photo: Antoine Raffoul) clamped to stainless steel wires suspended The third is the element of the cladding itself. from the roof and bolted into the floor. Sockets The stone shields are detailed within the are permanently fixed in floor and ceiling on a main frames, and the metal sections of the •hi ~Lm grid pattern, and wires may be strung as re• large sliding aluminium windows become the quired to form hanging walls. : equivalent of moldings. Construction began in 1974, and the College moved in and entered upon the first academic Fourth scale I- year, in October 1978. With accommodation The fourth scale is formed by all that which for 3000 students the New Arts Building is fits within the framed enclosures, and is con• humming with activity. structed largely of wood. This is the domestic, The architects have said that 'the design aims and the smallest scale, and is designed to be to provide a coherent visual order which is distinct and separate, but also a smaller re• directly related to the functional order of the statement of the same essential idea. This is the building and is also an expression of its con• scale at which the building is handled, struction. This approach extends into the in• touched and used. terior design and furnishing of the building There is, in this way, a system by which the which is seen as a direct extension of the various elements of the building are not only architecture. The Arts Building is designed in related, but are also visibly interdependent. the belief that the quality of the visual en• Starting from the smallest scale, and working vironment matters and that it has a part to up to the largest. play in the educational function of the building'. The building was officially opened on 11 December 1978 by the President of Ireland, Dr Hillery. At that ceremony, at the reception which followed and at the evening party spon• sored by the design team, nothing but praise was expressed. Even the press and the stu• Fig. 17 dents themselves are very pleased with what The entrance hall, coffered slabs must be described as a very successful con• and cruciform columns clusion to 10 years of committed work by all (Photo: Antoine Raffoul) concerned.

Fig. 18 u Acknowledgments The two-level library and north light glazing (Photo: Antoine Raffoul) Architects Ahrends Burton and Koralek Fig. 19 Quantity surveyors 'Time for reflection' Patterson Kempster and Shortall (Photo: Antoine Raffoul) M & E engineers Varming Mulcahy Reilly Associates Acoustics consultants m Kenneth Shearer and Associates Landscaping Lanning Roper n Main contractor John Sisk and Son Ltd.

Fig. 19 top left The new college entrance from the Exposed services form a feature in the entrance Fig. 20 Fig. 21 Lamb & Flag Passage as seen from the hall, (Figs. 16 and 17) with a painted rainwater Brightly painted air ducts are used as a The double storey exhibition hall, and gallery new quadrangle pipe running alongside the cruciform-shaped feature (Photo: Antoine Raffoul) (Photo: Antoine Raffoul) columns.

The coffered floors are 400 mm overall depth, but the carefully detailed rebates 50 mm x Fig. 20 above 50 mm on the soffit of the rib reduced this. New squash courts with 'sets' over, Spans of 11.25 m x 8.55 m indicated a very viewed from the Robert Graves Room flexible floor, and precautions were taken to reduce relative deflections during construc• tion by loading two floors with stacked block- work before permitting block wall construc• — •ll|!||iwi tion to commence on the lower floor. This restriction was maintained throughout. Con• I' siderable difficulty was experienced in Em»7% achieving and maintaining the high standard of soffit finish required. Formwork arrises of the rebates deteriorated rapidly; coffers would stubbornly warp, and carefully taped joints i would sometimes leak. The results show, however, that the efforts made by all con• cerned to achieve a high quality 'as struck' Fig. 21 finish in white concrete have been successful. A garden building • typical outlook The library (Figs. 18, 19 and 20) is on two levels, and the sloping north-facing, glazed I roof provides illumination to both levels. The Fig. 22 right lower level, to the right of Fig. 18, projects The elements from which the building is made under Fellows' Square. Air supply ducts boldly 25 Fig. 13 (below) 45° chamfered corners of walls are a strong feature of the bu Iding, both externally and internally (Photo: Antoine Raffoul)

Fig. 12 The south face, faceted, and cream granite clad (Photo: Antoine Raffoul)

Fig. 14 The east face. The sharpness, clarity of line and meticulous detailing shown here are characteristic (Photo: Antoine Raffoul)

The staggered, cream, granite-clad faces pro• vide both shelter to the occupants from the noise of Nassau Street, and a delight of wand• ering walls and peeping windows, glimpsed through the curtain of trees to the passer by (Figs. 12, 13 and 14). Whereas the granite cladding to the new library is 100 mm thick, that of the Arts Building from the same source, due to finan• cial stringency, is only 35 mm. This created problems of detailing, of both stones and supports, particularly where a splay corner stone follows a wall which turns through 45°. In order to make the stone appear continuous around a corner, it was mitred and glued at the factory. Design of suitable supports for such a stone which allows for vertical shor• tening of a four storey high wall, thermal ex• pansion of the granite on a south aspect, and variation of wall location from the theoretical, produced a fine exercise in tolerances, hori• zontal, vertical and personal. T*r>>ugbiHy*G«fcry Within, use of applied finishes has been kept to a minimum, and the white concrete cof• fered ceilings and painted block partitions are shown at the entrance to the Douglas Hyde Gallery, (Fig. 15).

Fig. 15 Interior surfaces showing the decorative use of a lignacite wall, and exposed coffered white concrete slab soffit as a ceiling (Photo: Antoine Raffoul) Circulation All staircases, ground floor common rooms Fig. 7 and bars, have direct access from a single West face, showing the flank wall of the colonnade. This colonnade faces towards the 400-seat lecture theatre unobtrusively tucked old college buildings, so that it is not only almost below ground and beneath the visibly part of the circulation system of the glazed accommodation in the middle college, but also helps to tie and identify the foreground new buildings with the old. It links the porter's (Photo: Antoine Raffoul) lodge at one end to the east quadrangle and the new squash court buildings and 'sets' at the other, with access to St. John's main garden. In the design of this most important ii in it aspect of the buildings we wanted particu• larly to invite curiosity and search. Only by walking through the buildings and experienc• ing them did we wish them slowly to be fully revealed and then naturally used. This, of Fig. 8 (below) course, is very much within the tradition of Interior of the main lecture theatre the pattern of Oxford colleges, and bearing in (Photo: Antoine Raffoul) mind the size of the new buildings, one which we wished to exploit. aspect of New Fellows' Garden, and the floor had to be kept up out of the water. The solution adopted was to span reinforced con• crete beams from back to front and to support these on a fabricated steel beam, 1.5 m deep Fig. 23 above spanning 18 m transversely, located directly South west paved court and end pavilion above the lecturers' dais. The beam supports, in addition, one storey of professors' accom• modation. Service ducts passing from front to rear between the concrete beams pierce the steel beam very significantly and neces• sitated the use of heavy plating and stiffening. The beam was concrete-cased, weighed approximately 20 tonnes and was brought to site in three sections. Stepping of the north face of the building has resulted in the crea• Fig. 24 left tion of peaceful courtyards (Figs. 9 and 10) Main colonnade from which all staircases around which the rooms of professors and and commonrooms have access lecturers are clustered. The building volume, which was displaced by stepping the north face, moved above the lecture theatres on the south face, and the new south side of the building follows the oblique line of Nassau Street, (Fig. 11).

Fig. 10 (below) A different view (Photo: Antoine Raffoul)

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Figs. 25 and 26 The design of the circulation within the Fig. 9 Oxford tradition intends to stimulate curiosity and invite search One of the enclosed, elevated courtyards (Photo: Antoine Raffoul)

Fig. 11 Model showing the varying arrangement of walls on the south face (Photo: John Donat)

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Fig. 28 Reflections of old and new 71 Fig. 27 top The main college bar faces south onto the quadrangle

Fig. 29 above Upper (soft) bar (cill to colonnade is above eye level) with view over gardens

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Fig. 4 Stepped north facade looking onto the new Fellows' Square (Photo: Antoine Raffoul)

Attempts were made to reduce the apparent sides collapsed quite quickly. Allowance was height by stepping the north face, in order to therefore made in the Bills for pumping the open up again the reduced Fellows' Square. site, if necessary. Individual pad footings The success of this can be seen clearly in Figs. were blinded immediately formation level was 4, 5 and 6. The roof line was kept down to that reached. The lower ground floor slab was of the new library, and the building was laid on 200 mm of no-fines concrete to avoid squeezed down, the ground floor being now impeding ground water flow, and the slab and Fig. 31 Fig. 33 below the level of Fellows' Square; the per• associated retaining walls were designed as The world within a world' Section showing relationships between missible 'squeezing' being constrained by the watertight to a level above expected flood structure, glazing, screens and interior high water table. Apparent height has also levels. During excavation, water flow was furnishings been reduced by earth banking. 'Remoulding' found to be far less of a problem than had caused the 400 seat lecture theatre (Fig. 8), been feared. Once the local water table had which projects clearly at the top of Fig. 3, to be been drawn down, the flow was easily con• tucked under the general accommodation, to tained, to the relief of all concerned. such good effect that its roof (extreme right The Edmund Burke Theatre of Fig. 4) and the upper part of its west flank The roof of the Edmund Burke Theatre is wall, are barely noticeable behind the bank generally of reinforced concrete beam and and shrubbery of Figs. 6 and 7. slab construction. Overall height of the theatre When trial pits were dug for the site investiga• had to be kept to the minimum; the roof level tion the inflow of water was such that pit had to be kept down to improve the open III!! 1 -4' V V V ILV-lLVmLvWli V V V 1' P"F"

tuni IUHUUHI t' IUHHHHHIII i v Fig. 5 jixuLmnLmm |i ,i 11 ,i |i ,i ,i y mm -U-U ii ii ii mi ii ti ii ti ti ii »i u^uuuij North face: the clear sloping glazing WTrirTjpqp V l V I'll I iOUUU: P forms the roof to the double-storey library STEP (Photo: Antoine Raffoul) lUHHHHHnrrtq -1HUI tl ,UUI II11 ll tLjJ4i4fJ Fig. 3 Models showing evolution of the design U li.li ii ii n ii pq from first planning approval (top) to building as built (bottom) (Photo: Antoine Raffoul) i : : in Hi i: l-l-t l-V- Fig. 32 Model of a 'set' unit IVl'VVVVV t:j:|«:i! V Wi-l-l'V The building form, for which planning per• mission was first granted in 1972, is shown at the head of Fig. 3. An appeal and public enquiry concerning the siting of the building \ in relation to Nassau Street was held and a revised building line moved the building about 14 m to the north, thus reducing the Fellows' I Square, and disrupting the relationship of the J new building with its existing companions. Paul Koralek and Patrick Stubbings con• sidered that the building in its revised location was unacceptable and they embarked upon successive strenuous and exhaustive exer• cises to remould and adapt the fixed volume of the building to a more confined setting. These are shown progressively in Fig. 3. The building originally approved is at the top, the alternatives and modifications progress down• wards, arriving at the building as built at the bottom. 21 The Room Koralek, of Ahrends, Burton and Koralek, was 1967, and to which the new Arts Building Within the minimum of space, the multiple considered more sympathetic to the aims of bears a strong affinity, being clad in the same Arts and Social functions of a student bed-sitting room or set • the college, whose stated requirements were light cream Wicklow granite), to the south is a problem of opposites. It's a place of work • by Nassau Street and its belt of flanking trees, Sciences Building 'a design involving one or two interlinked and sleep, a retreat, and a place to entertain, 31 and to the west by the Provost's House and new squares, of elegant proportions, whose a personal place, yet an identifiable part of a garden. Trinity College, style should be consistent with the historical larger community. In some respects it follows Dublin interest and architectural value of the site'. The outline brief and the site posed, in the directly the aims of the 'minimum living unit' Emphasis was placed on the desirability of architects' own words 'the problem of con• that Wells Coates worked on in the '30s and o retaining a substantial area of lawn immedi• centrating a large amount of accommodation '40s. Within this limited area, however, the ately to the south of the old library, and of on a restricted site, further restricted by the • ARCHITECTS: intention is to provide for these various func• preserving as many trees as possible. Pedes• desire to use the minimum site area without •>!••• AHRENDS, BURTON AND KORALEK tions and reconcile the conflicting needs to trian access to Nassau Street, exclusion of making a high building, and the intention to create above all somewhere with a sense of a traffic noise, and flexibility of accommodation form a well proportioned new square on the generosity. A place with a strong relationship were essential requirements of the building. site of the Fellows' Garden, a square com• to its site, and to the architecture of which it Peter Ryalls In addition the architect was urged 'to seek parable in scale to the older squares in Col• is a part. to provide facilities for staff and students lege and completing the pattern of these The sets are split into rooms which open out which would give the Faculties, Schools and squares, symmetrically about the central axis During the years 1938 to 1958 the number to the gardens, and the bedrooms are enclosed Departments concerned a new sense of of the college'. -r- of students at Trinity College increased slowly within the stone towers. There is a change of identity and community, yet preserve and from 1500 to 2000. Since that time the student The trapezoidal shape of the site created the level between these, to accommodate the develop those aspects of the present arrange• population has more than doubled, and in further problem of reconciliation between the stepping of the pavilions down the site. The J ments that encourage a sense of membership 1966 the College commissioned a develop• rectilinear forms of the buildings and squares rooms, in both the sets and the bed-sitting of a college with a rich diversity of activities'. ment study of the whole of the site. That of the College, and the oblique angle of the rooms, each have large sliding windows, The site (Fig. 1) lies in the Fellows' Garden, ; • i development plan determined the pattern of line of Nassau Street on the southern bound• opening so that in fine weather the whole PI 1 a fine and relatively restricted area of garden growth for the College and established the ary. The apparent mass of the building and its room can become a balcony. on the southern edge of the College. It is sur• height had to be in harmony with both the old design parameters for the new Arts Building. Timber sliding screens, and holland blinds re• rounded to the north-east by the new library and new libraries facing onto the new Fellows' ] Ideas were then sought from architects, and place curtains in the sets only, which are on (also designed by ABK and completed in Square (Fig. 2). of the two schemes submitted, that of Paul the south and west elevations. The screens double up as sunbreakers, room dividers, D grids on which to hang posters and so on, as well as providing visual privacy from adjacent sets. On the east and north elevations, window OB areas are much smaller, and curtained. In 9 these cases the towers themselves provide for r4t b visual privacy between adjacent rooms. The natural randomness of the positions of U l-T J these screens, is a very important element in 7 the design of the quadrangle elevations. It II II \ provides vitality and movement at the scale of use - the fourth scale.

Fig. 34 Fig. 35 Plan of typical bay, showing 'sets' and View through to bedroom; note change of ! bedsitting rooms with shared services level as pavilions step down the site

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Fig. 2 Section showing relationship of the new building to the old and new libraries (Reproduced by courtesy of the architects) 20 At night, the play of light against the cham• Armed with this strategy you have some sort of the ideas can be ruled out immediately and extended families may have been included in fered stone faces and through the screens and of standard by which to assess projects, not certain of them will in fact be general policy the programme on the grounds that there was brown blinds is particularly successful, which a rigorous mathematical technique but some• suggestions which could modify the strategy a demand for at least 100 units. How many proved a very happy surprise, not entirely thing to go by and one which will produce a in the future, and some of them will be of those actually built to date in response to foreseen. slightly different result from the rigorous general suggestions for projects of a certain this suggestion, have been taken up? How Finally the attic storey with roof terraces on mathematical technique could such be de• kind; more old people's day centres as many dogs have in fact been caught ? Whereas the south and west provides flats for Fellows vised. Any mathematical algorithm that could opposed to a day centre in a particular it was planned to build flats at £12,000 per as well as rooms with an entirely different be envisaged would tend to allocate all ex• location. All the rest have to be analyzed. unit, how many have in fact worked out at character. These are 'roof rooms' with lofty penditure to one category which produced You do not want to spend too long on the £12,000 plus inflation and how many have spaces between low eaves lines, and with most in terms of units of welfare up to a cer• projects which have very little hope of being cost more than that ? spectacular views over the gardens and over tain point at which some other category accepted or in the first instance on those Monitoring of indicators Oxford. became marginal and then expenditure would which are certain to be accepted. You need It is proposed that monitoring of all these be allocated to that second category leaving to concentrate on the.marginal projects, but indicators should go on as soon as the first some categories with nothing. We are likely you don't know which ones these are going year's programme begins to be implemented. to produce a list of projects in practice which to be so one stage in the process is to make a A group of officers will meet regularly to allocates something to all categories of ex• review these matters and a systematic report rough estimate of the cost of all and compare penditure. This could be argued for on the on past projects will be part of the annual the total with the resources available. You can Fig. 36 grounds that we do not know and do not assessment of the current situation in the then rule out a lot of projects and move to the Stone towers provide privacy between even have a rough subjective assessment of inner city areas which officers will put up to next stage which is to concentrate effort adjacent bay windows the marginal contributions to welfare of differ• Partnership Committees and other committees immediately on those left. ent categories of expenditure so it is quite responsible when they begin preparing the When decisions have to be made on the rational to play safe and give something to programme document for the following year, Fig. 37 marginals you need to analyze more fully the all, even on some random basis. But there is rolling forward their three-year inner city Night view; lighting behind random screen certain runners because these also will have probably also an element of political necessity programme for another year. positions creates a varied and changing in this kind of solution. to be justified in the programme document. There are many instances of housing schemes spectacle Money This is a two bites at the cherry approach, and giving grey hairs to architects and quantity St. John's is a building that has to work at a one which local authorities are not very well surveyors and bringing finance committees The next step after determining the strategy number of levels, and which seeks both to geared to following. There is always great to despair with their extra costs while yet is to decide how much money there is to be draw references from Oxford as well as visual reluctance in local authority to produce rough housing contented tenants and becoming spent. There will be a specific sum allocated metaphors from the collegiate tradition. estimates with the danger than one may be part of a wider process of successful improve• under the Urban Aid grant, but this will be It is probably the end of an era of college ex• held responsible for them. Rough estimates of ment. It is hoped that there will be a further subject to a 25% contribution from the local il •«••««••••••••••• tensions of this magnitude, and strangely is cost require rough details of content, and these stage of monitoring not of individual projects • *•••••• authority. The contribution is asked for within 200 yards or so of that first university are often difficult to extract. but of overall achievement of results produced because it is thought that grants normally commission for Somerville's graduate building by all the projects working together. This ::MK::::::::: bring back revenue to the local authority in designed over 20 years ago. Whilst this article Performance indicators latter form of monitoring will go back to the some form directly or indirectly, like increased covers in some detail the design of a single Details of content and performance are im• strategy decisions and see how far they have rates and increased activity in the area, but in i iiriiTlitnin-Ti • n • p m r building, nevertheless I hope it exposes wider portant in the whole process. It is being been achieved, whether there has in fact been any case it is likely that local authorities will ia»ii*««a«!i!fli«iiia> iri ideas and attitudes that have grown up in the emphasized that every project listed in an inner a noticeable improvement in housing or the in effect have their 25% contribution returned I IIUUdllaJIJilllJilLjli intervening years. There has always been a city programme should have as many per• environment overall regardless of how far to them in the form of needs grant under the • • • - • « «* m m a - m m k. m m m m i close relationship between the architecture formance indicators as possible listed against individual projects may have succeeded or settlement of the rate support grant in the t •. iHI i• iiriiiiiimi of our college building and much of our it. If you argue for additional social workers otherwise. One imaginative suggestion is following year. office, laboratory, and industrial work. you must show how many you have at that this sort of monitoring might be assisted Each has nourished the other, and St. John's, The grant may be spent on revenue, recurring present and how they compare with the by a series of before and after photographs perhaps more than any of our work so far, projects or on capital. If any grant is spent on national average per 1000 of population, covering as large an area as possible. reflects this variety of sources - as well as our the former then there is a commitment in generally and in stress areas. If you want a Monitoring will also go a stage further back attitudes, and architectural values, applied in future years which will reduce the amount of 'drop in' centre for youths, you must estimate and look at the change in certain indicators on this event to an historic site. new money available in those years. If it is how many are likely to use it and what class of a higher level of generality, at the kind of spent on capital works then the revenue youths over what area you expect it to cater things which study teams used to measure consequences in future years have to be for. Whereas we meet all the difficulties of malaise in the Inner City - crime, vandalism, assessed. These consequences are more likely comparing unlike with unlike which have poor health, unemployment and low educa• to be expenditure than income, and where been described in the paragraphs above, when tional standards. local authorities are now spending 20% of we try to decide whether a social worker is their recurrent funds on servicing debt they worth more than a dog catcher, there must Measurement of achievement are becoming increasingly anxious to avoid nevertheless be some level of dealing with You measure achievement for the purpose of capital works which may generate future social service referrals per week and some educational standards not in expenditure on expenditure and hence there is a further level of performance in terms of dogs caught new classrooms nor on pupil/teacher ratios argument for moving towards the economic per week which would positively rule one out but in terms of academic attainment and 'O' development side of urban renewal. against the other. and 'A' level passes. These things have to be It is unlikely that the Department of the The National Building Agency has been pro• measured in the long term. The programmes Environment will lay down revenue/capital ducing a management model to define the now being prepared will be implemented in ratios for expenditure of Urban Aid grant, but activities which have to be gone through in 1 979/80 and any buildings contained in them they will have to watch how the totals order to prepare and monitor an Inner City will not be completed until 1980/81 or after. between all authorities work out and they may Programme. The first classrooms built in response to the have to exercise some control in the future. present policies will not open their doors to Other financial resources will be available It becomes apparent from the model that the pupils for three or four years and the brighter from the Locally Determined Sector alloca• time available for the preparation of the first interior behind those doors will not have its tion which is not a grant but an authorization draft of the programme will be exceedingly effect on 'O' level achievements of those to raise loans. tight and although we have described above a two-stage process of rough estimates re• pupils until some years after that. Bending of main programmes fined later it is possible that yet a third itera• If there are improvements it will be hard to Then over and above these and other minor tion will be required because of the lack of demonstrate that they would not have taken sources of funds it is likely that as much time available to finalize the second stage place anyway through other influences. If again will be allocated to the inner cities satisfactorily. After the first draft of the pro• there is no improvement it will be possible to through the process described as the bending gramme has been produced and submitted to argue that things could have been actually of main programmes, the allocation by central the Department of the Environment for con• worse if our policies had not been imple• and local government of an increased propor• sideration, it will be desirable to have another mented. However, difficult as it may be to tion of money available under for instance, run through the projects, checking their assess these things they will be the real education or housing, to inner city areas. cost estimates and the other measurements of measure of improvement and it is only through Where the local authority does the bending what they are supposed to achieve, before the these measures in the distant future that we there is no overall increase in the funds avail• programme is finalized in January to March will know the real value for money achieved able to it. Where the bending is done by immediately before the beginning of the by our policies for the Inner City. central government then the local authority financial year. All this will require a consider• Clearly we must have faith. We must have with the inner city problem is that much able amount of effort particularly by the faith in ourselves to deal sensibly with this better off at the expense either of other local quantity surveyors and planning teams. most complex problem. And I do believe that we can be successful provided we are not too 1 authorities or of other categories of govern• Once you have all these indicators recorded ment expenditure. you usethem not only to decide which projects intoxicated by the technological possibilities are to be included in the programme, you use of this last quarter of this century which appear The next step is to look at all the ideas and them to see that you are getting value-for- to ignore the need for balanced human bids which have been submitted for the inner money in another sense in actual performance judgement exercised in the best interests of city programme which has to be drawn up Main contractor: Johnson & Bailey as the projects are implemented. Housing for our community. 1 (Photos: Arup Associates) each year by the end of the summer. Certain the ultimate suggestion that the whole prob• lem is a moral one and therefore requires a after having dealt with the hard core of slums in those areas both public and private invest• moral solution so all the money available Value for money in was in danger of going too far and destroying ment in the small numbers of dwellings im• should be put into building a temple for a with the bad much that was good; disen• proved will not have been well made. particular religious faith I urban renewal chantment with a lot of the new housing Perhaps the local housing supply/demand built to replace the slums; realization that No rigorous analysis can be found which will situation was different. Perhaps more homes much of the remaining older housing was not produce a list in priority order, but it seems were owned by people with inadequate funds Peter Dunican only a still valuable resource in terms of reasonable to try to provide a guide by setting to pay their part of the costs. Perhaps the housing supply, but also made a vital contri• down the general aims of the inner city policy local authority was less than effective in deal• This paper was originally presented at the bution to urban environmental balance and as we see them. Public Works Congress, November 1978 ing with environmental sores. structure. Therefore, we could not afford to On the other hand, overall success and value- You have to start withthe overall strategydeci- under the auspices of The Institution of go on throwing it away with such brash for-money might have been achieved by more sion between on the one hand improving the Structural Engineers. abandon. public funding of rehabilitation; or by a more area as such and on the other hand doing some• INTRODUCTION Rehabilitation is here to stay. Clearly this is ready facility to clear the worst properties and thing for the people who live in it. The former not a unique view. I believe that the pendu• infill with new housing designed to knit would justify more parks and open spaces, I propose to discuss this most important sub• lum's swing now needs to be checked and sympathetically with the old. The first option more buildings which would benefit people ject under two headings; headings directly " even given a gentle nudge in the other direc• was impossible because of the relative in• I-' from the outer areas and more industries concerned with two rather disparate aspects tion. In fact, I believe that we are fast flexibility of the grant system, or lack of which would employ labour from the outer of the urban renewal need: firstly, the general approaching the stage at which the broad- incentive for landlords; the second, perhaps areas or outside the district altogether. The problem of our older, worn out, or nearly brush area rehabilitation procedures in opera• because of restraints on acquisition, un• latter would justify more in the way of hous• worn out housing that still exists close to the tion since 1969 will have achieved as much as realistic planning demands, 'yardstick' inflex• ing and social welfare. You could of course heart of most towns; the kind of problem we can expect of them as the primary means ibility, or for private developers, the relatively go for a third overall strategy, often described which we have been tackling in the last de• to relieve bad housing conditions while greater attractions and fewer problems of as planned orderly withdrawal, which would cade through the widespread use of area making the best use of our resources to that building on green-field sites. be to suggest that in renewing the inner cities rehabilitation - General Improvement Areas and, more recently. Housing Action Areas. end. at all we are playing Canute against an irresist• Very high density areas ible and overwhelming tide of economic This is a field in which we have a substantial These methods have been dramatically suc• Yet another type of housing area comes to forces. Practically speaking this third choice working experience and on which we can cessful in promoting the very concept of mind - and this is one that predominates in, is not open to us since fortunately the decision base an assessment about the future. And rehabilitation - and to show the importance of but is not exclusive to, the North and Mid• to have an inner cities programme has already also where the question of value-for-money its place in the processes of urban renewal. lands; the very high density areas of two-up/ been made, but it is a logical possibility, some is not too elusive; all we have to do is decide They have demonstrated where rehabilitation two-down, narrow fronted cottages - the Fig. 3 will argue for it, and decisions will have to the measure of future usefulness and accept• can be technically feasible, economically product of the later stages of the Industrial City of Birmingham, 1946 stand up to criticism from those who do. ability of rehabilitated dwellings, related to viable, socially desirable and rewarding. But Revolution, and in which the housing is often (Photo: Aerofilms) In one way, however, inner city programmes financial expenditure upon them, compared they have also shown us where it is not! still side by side with heavy industry. Some will be fighting against economic trends. The with that of newly built homes. This may not In the future, I believe that if we wish to of these were declared as General Improve• aim of inner city policies is to direct expendi• be as difficult as it appears provided we set Fig. 4 maintain a fully cost-effective response to the ment Areas, but more recently, and although ture towards people and areas which would up the right equations. Centre of Birmingham, 1974 physical, social, economic and conservationist often predominantly owner-occupied, they be missed out if a free market were left to (Photo: Aerofilms) The second heading is the very special and needs that relate to housing, we must move are a target for the Housing Action Area allocate it to areas of lowest cost. Building particular problem of our inner cities; and towards a more selective, sensitive and flexible system. costs are likely to be higher in all the inner this is a complex amalgam of physical and approach to rehabilitation - and provide the ! With this type of area we need to look closely city areas than they would be in the rest of social problems concerned not only with procedural and financial support systems that ; at some of the physical characteristics of both the country, so value-for-money is by that much housing, but also with industry, commerce, will allow this. At the same time we should the dwellings and their environment - in order diminished for every inner city building project. communications, education, civic and govern• seek a more natural balance between re• to set the scene for an assessment of rehabili• mental functions - and with the inter• habilitation and new-build - and establish tation value-for-money. I believe we will Project grouping action of all these elements. In this field, in systems that are flexible enough to allow the conclude that some such housing must con• Having decided on the overall strategy in these contrast with the first, we certainly do not two elements to work together in the success• tinue to be upgraded for long-life and must be terms you need to break it down further in have a decade of experience to help us - at ful achievement of urban renewal. conserved, even at increased cost, as an im• terms of the main headings under which pro• least not of a positive, remedial and creative In looking for more specific answers for the portant part of regional heritage - and since, l. jects will be grouped. Headings will be hous• kind. future, we must be certain to look fully and in the right circumstances, it may continue to ing, employment creation, transport, health, However, we are beginning to identify the dispassionately at the situations and problems provide useful homes in high demand. But education, sports and leisure, environmental nature of the problems and their past causes, we now have in clear focus from our past ex• I also believe we will conclude that this will improvement, personal social services, in• but we have barely begun to take action; let perience. I will now try to help this process. not be socially or cost-effective on the scale dustrial development. It should be possible alone decide what that action should be and We have some areas - perhaps mainly in the we have envisaged or attempted so far. to put these headings into priority order or to how it could be achieved. But we do know South of England, and of a type we could For the majority of such housing, though by give them some sort of weighting - so much without any doubt that the full evaluation and label as 'early suburbs' - of fairly varied, no means all - and this could also apply to per cent of the programme to housing, and solution of the inner city problem will require moderate density housing, mainly owner- many 'early suburb' areas - the achievement so much per cent to sports and leisure, and new depths of thinking, new heights of occupied, built in the period say 1870/1920; of value-for-money will, I believe, result from so on. The sort of choice to be exercised here determination and a much wider breadth of areas in which most dwellings lacked basic a more decisive recogniton that rehabilitation, will be between: co-ordinated expertise. amenities, needed repair, and had an environ• and the financial investment in it, has only a (a) going for the old familiar pattern of In the inner cities we will be swimming against ment that had suffered from the effects of short-term objective; that it is to give im• local authority expenditure, biased towards the natural tide of economic and social trends interloping industry, the motor vehicle, and mediate relief to intolerable conditions - and the inner city but otherwise unchanged with of the past 30 years which has been to re• general public neglect. is a gap-filling expedient until, within the 75% of capital spending going on housing, or shortest possible time, new homes are built. create and serve demands that have ceased Because of local housing pressure, the lack The common, critical physical characteristics (b) recognizing the claims of the social ser• to exist. We must be successful. We shall of alternatives, the extensive use of grant- of the 'two-up/two-down' dwellings that I vices some of which bring back no dividends have to do our sums much more differently aided private improvement of the dwellings, referred to are these: first, their size and shape. to the general public like day centres for the than we do them for the generality of housing and public improvement of the environment, They are often very narrow fronted - as little elderly, while others bring unquantifiable rehabilitation within predominantly residen• facilitated by the moderate density, some such as 3 or 4 m - and have an even narrower back dividends, like youth clubs which it is thought tial zones. There will be more complex, less areas have been transformed. Clearly.and with extension, containing a scullery and possibly keep youth away from crime, but all of which tangible criteria to identify in deciding re• only limited, occasional infill, they will remain a small extra bedroom above. No bathroom; ment, geography or fringe benefit will have Yet the programmes being proposed for are being pressed by a large number of lationships between cost and benefit - in as areas that provide decent housing standards only an outside WC, often shared. These cot• been left out of account. This list will have to inner cities contain projects of many different thoughful people, or deciding what represents true value-for- and encourage on-going private investment tages may have a theoretical capacity of four be reviewed on some sensible and accepted kinds and the policies announced in the White (c) moving into the comparatively new area money. - perhaps for yet another 50/60 years. In fact, or five persons, but their total floor area can be basis to a length that can be accommodated Paper envisage breaking into areas of activity of industrial development, where many worth• some of those areas are regarded by both as little as two-thirds of that we expect for within the available resources. in which local authorities have barely trodden while schemes will already have been tackled HOUSING RENEWAL young and old residents as far more desirable minimum-sized new dwellings. To provide an Now getting value-for-money means spend• in the past. All of these projects have to be by an army of people in the private sector We are all aware that there has been a gigantic and characterful than the brash, new, high inside bathroom and WC - without building ing money where it achieves most good, but weighed one against another if common who can probably do as well as the small swing of the pendulum during the last decade density estates, so often less well located for expensive, space-consuming and sometimes most has to be defined. If two mines produce sense decision-making is to prevail. We can• group under an industrial development officer away from wholesale clearance towards re• urban amenities, education and employment. environmentally disastrous extra back exten• lead and gold you cannot compare their out• not afford to neglect democratic communal in the Town Hall, where there are arguments habilitation. The numbers of outworn or ill- And financial expenditure in those areas, even sions, or providing a very poor internal layout put in tons, without taking into account the decision-making. for initial subsidies in the form of reduced equipped homes improved with the aid of if it had been at the same level as for new - can reduce the four or five person dwelling price of lead and gold. It is what I would call rents or interest-free loans but difficulties in We could be concerned with problems involv• Government grants and procedures operating housing, would have been very good value- to one which, to modern acceptable standards, the apples and pears argument. Where there assessing which projects will really take off ing choices between housing and environ• during that period reached its peak in the for-money; at anything less than these costs will only house two or three. Individually, de• is no market and no price, there is no common once the initial subsidies are withdrawn, but ment and something else perhaps altogether early '70s. At the same time construction of it has been a bargain! pending on existing occupancy, this may be denominator between the criteria. Social where, at least, there should be some rate of much more important. If I could give an new housing, both in the public and the private But unfortunately there are not many areas enough and may be economic. But while economists have tried to find an objective return on the money spent, or example: a typical inner city authority is now sector, fell dramatically from the numerical where success has been so absolute. There recognizing that we now have huge shortages standard, other than price, to measure whether preparing its programme from a collective (d) environmental works, 'cosmetic treatment targets and achievements of the '60s. are others, perhaps physically similar, and of small dwellings, mass concentrations of one set of circumstances leaves people better ideas paper which contains suggestions as of eyesores' too much of which without We also know there were several factors that also declared as General Improvement Areas them in large areas of identical two-up/two- off than some other set of circumstances, but diverse as special types of housing for ex• anything else to back it up, does smack of the precipitated and subsequently sustained that - with similar types of action intended or down cottages is unlikely to be a realistic or so far very few useful rules have been estab- tended families, more social welfare officers, planned orderly withdrawal strategy which pendulum swing: economic restraints; a initiated - but where the downhill trend has socially acceptable solution. 18 lished or even laid down. interpreters, a Caribbean cultural centre and we mentioned and ruled out earlier. new awareness that sweeping clearance barely been disturbed, let alone reversed. And There are two other spatial features that are narrow streets, no front gardens, only rudi• Fig. 1 Fig. 2 expensive remedial problems is not exclusive hand in determining overall trends of supply/ important; staircases often so narrow and mentary back yards, filled almost to capacity City of London, 1 955 City of London, 1975 to rehabilitation. There are plenty of other demand and developing overall strategies: on steep that, for long-term acceptability, they by back extensions. Without at least some (Photo: Aerofilms) (Photo: Aerofilms) 'headlines' to tell us of the disasters befalling the other, in deciding what action and expen• may have to be replaced and lower-than- clearance there may be no hope of providing much newer estates! diture is appropriate for quite small groups of tolerable ceilings in back extensions. If, in even limited car parking, or play areas for I believe that, however difficult it is to quantify dwellings and their environment. dealing with these, the Building Regulations young children, or to plant some much them, if we consider the balance of those In my view, unless these changes of emphasis, have to be satisfied, the practical and cost needed trees. Invariably, in some part of any there are two, more general, and unfortunately decade's experience, we will recognize that results - and also take account of the hidden policy, and method are introduced fairly problems can be critical, and the already given area, there will be a concentrated prob• less tangible factors that we ought to con• among the results of rehabilitation so far can factors of 'overheads' and building resources quickly, we will look back in only a few years restricted living space even further reduced. lem of noise, pollution and congestion from sider in the value-for-money equation. be found some significant conclusions. - we will conclude that we should be looking and be startled to discover just how little we Features of their construction and repair con• inter-mingled industry. Utility services may One of these is the question of the productive There are many thousands of rehabilitated in the quite near future for a new formula of have achieved and how much money and dition that we have to contend with are these: be completely outworn. And the environ• use of our construction industry resources. dwellings on which there has been high ex• policies, procedures, financial incentives and other resources we have spent in the process. distortion through settlement, rising damp, ment may have suffered generally from years Rehabilitation, by its very nature, is labour- penditure of public and private money - aimed allocations that allows the following to We will not have had value-for-money. perished and deformed roofs, half thickness of blight and of poor street maintenance, the intensive. In current circumstances some may at achieving long-life - but where it is clear happen: Except in the inner cities I believe that there party walls, no thermal insulation, damp continued presence of derelict, bombed sites, consider this an absolute benefit: but this that these homes will not provide the quality (1) A modest return-swing of the pendulum in is one final and absolute test we could apply, through solid outside walls with perished joints and so on. Therefore, effective long-life re• intensive use of labour is, in fact, of high skills of accommodation and environment to fulfil which replacement by new homes becomes in many areas where enough money has been or rendering, infested structural timber, rotted habilitation and achievement of a reasonable that are in short supply even at this time. our aims. the primary means of dealing with fully out• spent to physically conserve, for long-life, social benefit from the money spent on im• windows - and, of course, the need for new Rehabilitation work, in particular, requires Equally, there are many thousands of cases worn stock that we do not wish to conserve any worthwhile, privately-owned older pro• proving the homes, will inevitably depend on or replacement services. those skills. But the work is also low- in which relatively high expenditure - up to for the long term. And this could well require perty - but in which there is now space avail• very high public expenditure on the environ• The problem is not that these defects and productive: some claim capital value output 'eligible limits' - has still not been sufficient a more elastic yardstick, plus possibly a local able for infill with new housing, as part of the ment. deficiences cannot be cured. Obviously they per man to be less than half that on new to achieve a level of repair and physical sound• loosening of planning and other controls, so renewal process. We will have to answer only can: it is physically possible. The problem is Larger properties housing construction. This arises because of ness that removes the need for excessive on• that infill replacement can be successfully one question. Is it a practical and profitable that, to cure them effectively - and to the There is one other general category of the complexity of the operations, wide varia• going maintenance and remedial costs; costs married with the best of the older stock and possibility for private developers to build and extent needed to give the dwellings reason• property whose physical characteristics are tions of repair even among small groups of that private individuals will not be able to environment we wish to conserve. sell that infill housing ? We may not wish them able life, without an unreasonable on-going again different, but worthy of note when con• apparently identical dwellings, lack of oppor• afford; work that will, therefore, not be done. (2) That, for the relatively small proportion of to do so, for any number of reasons: and maintenance commitment - can cost a lot of sidering rehabilitation value-for-money. They tunity to 'rationalize' or introduce industrialized Again the 'long-life' will not be achieved: older properties that are good enough to con• builders might not wish to do so, for reasons money; far more than may be catered for are the larger, four and five storey properties, methods, difficulty in phasing trade opera• and at least some of the money spent will serve for long-life, enough money is made other than profitability. Therefore the question within current grant levels; and leaving a far often closer to the centre, originally built for tions and in achieving effective programming have been wasted. Or, in the case of public available and actually spent to achieve that may be hypothetical. That does not matter. bigger gap than can be bridged by the the 'gentry', but now usually landlord-owned and site control of the work. agencies, there will be alarm at the level of aim. In individual cases that could well require If the answer, even to the hypothetical ques• present occupier. and multiple-occupied.They may be in smaller Certainly, in the case of contractors experi• un-budgeted maintenance costs - we have far higher input of public funds than hitherto. tion, is 'no' - this will imply fairly clearly that already seen some 'headline' reports. there is insufficient demand for, and market• In fact, many owner-occupiers of properties concentrations than the other categories, enced in rehabilitation, some of these diffi• It would certainly require great flexibility, both Inadequate grant support ability of housing in that area to ensure the in worst condition - and this applies particu• but are a prime target for HAA treatment and culties are reduced, and all the direct costs are of funding and procedures, to meet wide On the other hand, there are many other confidence and on-going private investment larly in some Housing Action Areas - are for conversion through the public agencies. presumably reflected in the sometimes start- variations of physical circumstance and private Because of their location, they can also be a lingly high tender figures. But one is less properties, of such inherent quality and desir• resource. And it is perhaps relevant here to needed to sustain the long-life for which we elderly or otherwise of limited means. They ability as to be potentially capable of very may find raising even a small mortgage loan part of the inner city problem. Again, for certain that there are not more general hidden express the view that, if we achieve in reality have initially hoped and paid. both practical and conservationist reasons, costs or other penalties that we should be long life - some indeed more than the 60 the 30 years' future life we have in the past If the answer is 'yes' then we are winning. either a practical impossibility or emotionally years we notionally allocate to new homes - many must be retained and given long life. considering, at least at a national or regional used as a measure of anticipated long-life THE INNER CITY PROBLEM intolerable. Even if they can bridge the gap, but which, because of inadequate grant sup• in the existing circumstances of their run• But not all of them I And again, even at higher level. performance in rehabilitation - then we might The inner city situation is much more complex, costs than we currently allow, we may not port and private funds, will not be up-graded just as well assume it will be 60 years. To intangible and incapable of rational resolution down area, there may be little incentive to do The other less tangible factor is that of the to reach that potential. In those cases costs as achieve some of the standards we expect of achieve 30 years must mean that the dwelling than the relatively simple question of housing so. Low market-value may make it a poor in• hidden costs of the administrative and pro• high, or even higher than those of new dwell• new housing. We have to decide how critical is equally as acceptable to the user, and of renewal. It cannot be subjected to over• vestment. Equally this can be a deterrent to cedural input by the local authority. It remains ings, would have provided good value-for- that is. equally sound structure, as a new one. simplified tests. In fact it usually begins in effective action by a public agency - such as hidden more often in ignorance and by the money. the local authority, or a housing association; In these properties, problems and high costs absence of hard information than by intent. (3) That, for the remaining sub-standard quite another place; a place in which rationale the total cost of acquisition and full improve• arise particularly in achieving adequate sound Some say jt is a 50% oncost. Others say it is Apart from the very obvious and essential older stock, there is a more positive recogni• and logic do not reign as they should. ment and repair may far exceed even an up• insulation and fire separation between flats, closer to 100%. We need to know. Otherwise short-term relief of bad conditions in countless tion that rehabilitation is only a short-term But at some stage, sooner rather than later, graded market value. And market value is or in providing 'means of escape', in utilizing we cannot give the answer about value-for- thousands of other homes, often at relatively expedient for which financial expenditure an inner city programme will be prepared. It about the only firm element of the equation basements with low ceilings and poor day- money. However, equally, we will continue low cost, there is, of course, a substantial must be kept to the absolute minimum until will inevitably consist of a long list of mis• we can use to determine the cost/benefit of lighting, and in carrying out effective repair of to recognize that on the other side of the number of dwellings in which the higher replacement is possible. cellaneous ideas suggested by local authority rehabilitation, and how firm is this ? departments at district and county level, ornate facades and complex roof forms - as scales, the hidden costs of all the procedural expenditure and long-life aims have not been To achieve success in applying this formula Another feature of these areas that we can well as in putting right the full catalogue of and approval hoops we must go through to so sadly mis-matched. We got what we ex• will require more careful selection and judge• central government departments, voluntary hardly ignore is their environment. Overall constructional defects common in the smaller build new homes is not insubstantial! pected, and for the targeted costs. Regretfully ments than have been applied so far within the bodies and statutory undertakers, police and density is often extremely high - sometimes properties. I believe that, when we come to an assessment they may be less numerous than the others. broad boundaries of 'declared' rehabilitation academics, officials and politicians, gathered twice the figure we would normally tolerate Leaving aside the particular physical and of the more specific problems referred to Also - and we might consider this on the areas. But this greater care will be needed at in by a net spread deliberately wide to ensure for new low-rise housing. There may be social features of particular types of property, earlier, and to take full account of the last credit side - the problem of unexpected and both ends of the assessment scale; on the one that no area either of direct or indirect involve- There are two other spatial features that are narrow streets, no front gardens, only rudi• Fig. 1 Fig. 2 expensive remedial problems is not exclusive hand in determining overall trends of supply/ important; staircases often so narrow and mentary back yards, filled almost to capacity City of London, 1 955 City of London, 1975 to rehabilitation. There are plenty of other demand and developing overall strategies: on steep that, for long-term acceptability, they by back extensions. Without at least some (Photo: Aerofilms) (Photo: Aerofilms) 'headlines' to tell us of the disasters befalling the other, in deciding what action and expen• may have to be replaced and lower-than- clearance there may be no hope of providing much newer estates! diture is appropriate for quite small groups of tolerable ceilings in back extensions. If, in even limited car parking, or play areas for I believe that, however difficult it is to quantify dwellings and their environment. dealing with these, the Building Regulations young children, or to plant some much them, if we consider the balance of those In my view, unless these changes of emphasis, have to be satisfied, the practical and cost needed trees. Invariably, in some part of any there are two, more general, and unfortunately decade's experience, we will recognize that results - and also take account of the hidden policy, and method are introduced fairly problems can be critical, and the already given area, there will be a concentrated prob• less tangible factors that we ought to con• among the results of rehabilitation so far can factors of 'overheads' and building resources quickly, we will look back in only a few years restricted living space even further reduced. lem of noise, pollution and congestion from sider in the value-for-money equation. be found some significant conclusions. - we will conclude that we should be looking and be startled to discover just how little we Features of their construction and repair con• inter-mingled industry. Utility services may One of these is the question of the productive There are many thousands of rehabilitated in the quite near future for a new formula of have achieved and how much money and dition that we have to contend with are these: be completely outworn. And the environ• use of our construction industry resources. dwellings on which there has been high ex• policies, procedures, financial incentives and other resources we have spent in the process. distortion through settlement, rising damp, ment may have suffered generally from years Rehabilitation, by its very nature, is labour- penditure of public and private money - aimed allocations that allows the following to We will not have had value-for-money. perished and deformed roofs, half thickness of blight and of poor street maintenance, the intensive. In current circumstances some may at achieving long-life - but where it is clear happen: Except in the inner cities I believe that there party walls, no thermal insulation, damp continued presence of derelict, bombed sites, consider this an absolute benefit: but this that these homes will not provide the quality (1) A modest return-swing of the pendulum in is one final and absolute test we could apply, through solid outside walls with perished joints and so on. Therefore, effective long-life re• intensive use of labour is, in fact, of high skills of accommodation and environment to fulfil which replacement by new homes becomes in many areas where enough money has been or rendering, infested structural timber, rotted habilitation and achievement of a reasonable that are in short supply even at this time. our aims. the primary means of dealing with fully out• spent to physically conserve, for long-life, social benefit from the money spent on im• windows - and, of course, the need for new Rehabilitation work, in particular, requires Equally, there are many thousands of cases worn stock that we do not wish to conserve any worthwhile, privately-owned older pro• proving the homes, will inevitably depend on or replacement services. those skills. But the work is also low- in which relatively high expenditure - up to for the long term. And this could well require perty - but in which there is now space avail• very high public expenditure on the environ• The problem is not that these defects and productive: some claim capital value output 'eligible limits' - has still not been sufficient a more elastic yardstick, plus possibly a local able for infill with new housing, as part of the ment. deficiences cannot be cured. Obviously they per man to be less than half that on new to achieve a level of repair and physical sound• loosening of planning and other controls, so renewal process. We will have to answer only can: it is physically possible. The problem is Larger properties housing construction. This arises because of ness that removes the need for excessive on• that infill replacement can be successfully one question. Is it a practical and profitable that, to cure them effectively - and to the There is one other general category of the complexity of the operations, wide varia• going maintenance and remedial costs; costs married with the best of the older stock and possibility for private developers to build and extent needed to give the dwellings reason• property whose physical characteristics are tions of repair even among small groups of that private individuals will not be able to environment we wish to conserve. sell that infill housing ? We may not wish them able life, without an unreasonable on-going again different, but worthy of note when con• apparently identical dwellings, lack of oppor• afford; work that will, therefore, not be done. (2) That, for the relatively small proportion of to do so, for any number of reasons: and maintenance commitment - can cost a lot of sidering rehabilitation value-for-money. They tunity to 'rationalize' or introduce industrialized Again the 'long-life' will not be achieved: older properties that are good enough to con• builders might not wish to do so, for reasons money; far more than may be catered for are the larger, four and five storey properties, methods, difficulty in phasing trade opera• and at least some of the money spent will serve for long-life, enough money is made other than profitability. Therefore the question within current grant levels; and leaving a far often closer to the centre, originally built for tions and in achieving effective programming have been wasted. Or, in the case of public available and actually spent to achieve that may be hypothetical. That does not matter. bigger gap than can be bridged by the the 'gentry', but now usually landlord-owned and site control of the work. agencies, there will be alarm at the level of aim. In individual cases that could well require If the answer, even to the hypothetical ques• present occupier. and multiple-occupied.They may be in smaller Certainly, in the case of contractors experi• un-budgeted maintenance costs - we have far higher input of public funds than hitherto. tion, is 'no' - this will imply fairly clearly that already seen some 'headline' reports. there is insufficient demand for, and market• In fact, many owner-occupiers of properties concentrations than the other categories, enced in rehabilitation, some of these diffi• It would certainly require great flexibility, both Inadequate grant support ability of housing in that area to ensure the in worst condition - and this applies particu• but are a prime target for HAA treatment and culties are reduced, and all the direct costs are of funding and procedures, to meet wide On the other hand, there are many other confidence and on-going private investment larly in some Housing Action Areas - are for conversion through the public agencies. presumably reflected in the sometimes start- variations of physical circumstance and private Because of their location, they can also be a lingly high tender figures. But one is less properties, of such inherent quality and desir• resource. And it is perhaps relevant here to needed to sustain the long-life for which we elderly or otherwise of limited means. They ability as to be potentially capable of very may find raising even a small mortgage loan part of the inner city problem. Again, for certain that there are not more general hidden express the view that, if we achieve in reality have initially hoped and paid. both practical and conservationist reasons, costs or other penalties that we should be long life - some indeed more than the 60 the 30 years' future life we have in the past If the answer is 'yes' then we are winning. either a practical impossibility or emotionally years we notionally allocate to new homes - many must be retained and given long life. considering, at least at a national or regional used as a measure of anticipated long-life THE INNER CITY PROBLEM intolerable. Even if they can bridge the gap, but which, because of inadequate grant sup• in the existing circumstances of their run• But not all of them I And again, even at higher level. performance in rehabilitation - then we might The inner city situation is much more complex, costs than we currently allow, we may not port and private funds, will not be up-graded just as well assume it will be 60 years. To intangible and incapable of rational resolution down area, there may be little incentive to do The other less tangible factor is that of the to reach that potential. In those cases costs as achieve some of the standards we expect of achieve 30 years must mean that the dwelling than the relatively simple question of housing so. Low market-value may make it a poor in• hidden costs of the administrative and pro• high, or even higher than those of new dwell• new housing. We have to decide how critical is equally as acceptable to the user, and of renewal. It cannot be subjected to over• vestment. Equally this can be a deterrent to cedural input by the local authority. It remains ings, would have provided good value-for- that is. equally sound structure, as a new one. simplified tests. In fact it usually begins in effective action by a public agency - such as hidden more often in ignorance and by the money. the local authority, or a housing association; In these properties, problems and high costs absence of hard information than by intent. (3) That, for the remaining sub-standard quite another place; a place in which rationale the total cost of acquisition and full improve• arise particularly in achieving adequate sound Some say jt is a 50% oncost. Others say it is Apart from the very obvious and essential older stock, there is a more positive recogni• and logic do not reign as they should. ment and repair may far exceed even an up• insulation and fire separation between flats, closer to 100%. We need to know. Otherwise short-term relief of bad conditions in countless tion that rehabilitation is only a short-term But at some stage, sooner rather than later, graded market value. And market value is or in providing 'means of escape', in utilizing we cannot give the answer about value-for- thousands of other homes, often at relatively expedient for which financial expenditure an inner city programme will be prepared. It about the only firm element of the equation basements with low ceilings and poor day- money. However, equally, we will continue low cost, there is, of course, a substantial must be kept to the absolute minimum until will inevitably consist of a long list of mis• we can use to determine the cost/benefit of lighting, and in carrying out effective repair of to recognize that on the other side of the number of dwellings in which the higher replacement is possible. cellaneous ideas suggested by local authority rehabilitation, and how firm is this ? departments at district and county level, ornate facades and complex roof forms - as scales, the hidden costs of all the procedural expenditure and long-life aims have not been To achieve success in applying this formula Another feature of these areas that we can well as in putting right the full catalogue of and approval hoops we must go through to so sadly mis-matched. We got what we ex• will require more careful selection and judge• central government departments, voluntary hardly ignore is their environment. Overall constructional defects common in the smaller build new homes is not insubstantial! pected, and for the targeted costs. Regretfully ments than have been applied so far within the bodies and statutory undertakers, police and density is often extremely high - sometimes properties. I believe that, when we come to an assessment they may be less numerous than the others. broad boundaries of 'declared' rehabilitation academics, officials and politicians, gathered twice the figure we would normally tolerate Leaving aside the particular physical and of the more specific problems referred to Also - and we might consider this on the areas. But this greater care will be needed at in by a net spread deliberately wide to ensure for new low-rise housing. There may be social features of particular types of property, earlier, and to take full account of the last credit side - the problem of unexpected and both ends of the assessment scale; on the one that no area either of direct or indirect involve- the ultimate suggestion that the whole prob• lem is a moral one and therefore requires a after having dealt with the hard core of slums in those areas both public and private invest• moral solution so all the money available Value for money in was in danger of going too far and destroying ment in the small numbers of dwellings im• should be put into building a temple for a with the bad much that was good; disen• proved will not have been well made. particular religious faith I urban renewal chantment with a lot of the new housing Perhaps the local housing supply/demand built to replace the slums; realization that No rigorous analysis can be found which will situation was different. Perhaps more homes much of the remaining older housing was not produce a list in priority order, but it seems were owned by people with inadequate funds Peter Dunican only a still valuable resource in terms of reasonable to try to provide a guide by setting to pay their part of the costs. Perhaps the housing supply, but also made a vital contri• down the general aims of the inner city policy local authority was less than effective in deal• This paper was originally presented at the bution to urban environmental balance and as we see them. Public Works Congress, November 1978 ing with environmental sores. structure. Therefore, we could not afford to On the other hand, overall success and value- You have to start withthe overall strategydeci- under the auspices of The Institution of go on throwing it away with such brash for-money might have been achieved by more sion between on the one hand improving the Structural Engineers. abandon. public funding of rehabilitation; or by a more area as such and on the other hand doing some• INTRODUCTION Rehabilitation is here to stay. Clearly this is ready facility to clear the worst properties and thing for the people who live in it. The former not a unique view. I believe that the pendu• infill with new housing designed to knit would justify more parks and open spaces, I propose to discuss this most important sub• lum's swing now needs to be checked and sympathetically with the old. The first option more buildings which would benefit people ject under two headings; headings directly " even given a gentle nudge in the other direc• was impossible because of the relative in• I-' from the outer areas and more industries concerned with two rather disparate aspects tion. In fact, I believe that we are fast flexibility of the grant system, or lack of which would employ labour from the outer of the urban renewal need: firstly, the general approaching the stage at which the broad- incentive for landlords; the second, perhaps areas or outside the district altogether. The problem of our older, worn out, or nearly brush area rehabilitation procedures in opera• because of restraints on acquisition, un• latter would justify more in the way of hous• worn out housing that still exists close to the tion since 1969 will have achieved as much as realistic planning demands, 'yardstick' inflex• ing and social welfare. You could of course heart of most towns; the kind of problem we can expect of them as the primary means ibility, or for private developers, the relatively go for a third overall strategy, often described which we have been tackling in the last de• to relieve bad housing conditions while greater attractions and fewer problems of as planned orderly withdrawal, which would cade through the widespread use of area making the best use of our resources to that building on green-field sites. be to suggest that in renewing the inner cities rehabilitation - General Improvement Areas and, more recently. Housing Action Areas. end. at all we are playing Canute against an irresist• Very high density areas ible and overwhelming tide of economic This is a field in which we have a substantial These methods have been dramatically suc• Yet another type of housing area comes to forces. Practically speaking this third choice working experience and on which we can cessful in promoting the very concept of mind - and this is one that predominates in, is not open to us since fortunately the decision base an assessment about the future. And rehabilitation - and to show the importance of but is not exclusive to, the North and Mid• to have an inner cities programme has already also where the question of value-for-money its place in the processes of urban renewal. lands; the very high density areas of two-up/ been made, but it is a logical possibility, some is not too elusive; all we have to do is decide They have demonstrated where rehabilitation two-down, narrow fronted cottages - the Fig. 3 will argue for it, and decisions will have to the measure of future usefulness and accept• can be technically feasible, economically product of the later stages of the Industrial City of Birmingham, 1946 stand up to criticism from those who do. ability of rehabilitated dwellings, related to viable, socially desirable and rewarding. But Revolution, and in which the housing is often (Photo: Aerofilms) In one way, however, inner city programmes financial expenditure upon them, compared they have also shown us where it is not! still side by side with heavy industry. Some will be fighting against economic trends. The with that of newly built homes. This may not In the future, I believe that if we wish to of these were declared as General Improve• aim of inner city policies is to direct expendi• be as difficult as it appears provided we set Fig. 4 maintain a fully cost-effective response to the ment Areas, but more recently, and although ture towards people and areas which would up the right equations. Centre of Birmingham, 1974 physical, social, economic and conservationist often predominantly owner-occupied, they be missed out if a free market were left to (Photo: Aerofilms) The second heading is the very special and needs that relate to housing, we must move are a target for the Housing Action Area allocate it to areas of lowest cost. Building particular problem of our inner cities; and towards a more selective, sensitive and flexible system. costs are likely to be higher in all the inner this is a complex amalgam of physical and approach to rehabilitation - and provide the ! With this type of area we need to look closely city areas than they would be in the rest of social problems concerned not only with procedural and financial support systems that ; at some of the physical characteristics of both the country, so value-for-money is by that much housing, but also with industry, commerce, will allow this. At the same time we should the dwellings and their environment - in order diminished for every inner city building project. communications, education, civic and govern• seek a more natural balance between re• to set the scene for an assessment of rehabili• mental functions - and with the inter• habilitation and new-build - and establish tation value-for-money. I believe we will Project grouping action of all these elements. In this field, in systems that are flexible enough to allow the conclude that some such housing must con• Having decided on the overall strategy in these contrast with the first, we certainly do not two elements to work together in the success• tinue to be upgraded for long-life and must be terms you need to break it down further in have a decade of experience to help us - at ful achievement of urban renewal. conserved, even at increased cost, as an im• terms of the main headings under which pro• least not of a positive, remedial and creative In looking for more specific answers for the portant part of regional heritage - and since, l. jects will be grouped. Headings will be hous• kind. future, we must be certain to look fully and in the right circumstances, it may continue to ing, employment creation, transport, health, However, we are beginning to identify the dispassionately at the situations and problems provide useful homes in high demand. But education, sports and leisure, environmental nature of the problems and their past causes, we now have in clear focus from our past ex• I also believe we will conclude that this will improvement, personal social services, in• but we have barely begun to take action; let perience. I will now try to help this process. not be socially or cost-effective on the scale dustrial development. It should be possible alone decide what that action should be and We have some areas - perhaps mainly in the we have envisaged or attempted so far. to put these headings into priority order or to how it could be achieved. But we do know South of England, and of a type we could For the majority of such housing, though by give them some sort of weighting - so much without any doubt that the full evaluation and label as 'early suburbs' - of fairly varied, no means all - and this could also apply to per cent of the programme to housing, and solution of the inner city problem will require moderate density housing, mainly owner- many 'early suburb' areas - the achievement so much per cent to sports and leisure, and new depths of thinking, new heights of occupied, built in the period say 1870/1920; of value-for-money will, I believe, result from so on. The sort of choice to be exercised here determination and a much wider breadth of areas in which most dwellings lacked basic a more decisive recogniton that rehabilitation, will be between: co-ordinated expertise. amenities, needed repair, and had an environ• and the financial investment in it, has only a (a) going for the old familiar pattern of In the inner cities we will be swimming against ment that had suffered from the effects of short-term objective; that it is to give im• local authority expenditure, biased towards the natural tide of economic and social trends interloping industry, the motor vehicle, and mediate relief to intolerable conditions - and the inner city but otherwise unchanged with of the past 30 years which has been to re• general public neglect. is a gap-filling expedient until, within the 75% of capital spending going on housing, or shortest possible time, new homes are built. create and serve demands that have ceased Because of local housing pressure, the lack The common, critical physical characteristics (b) recognizing the claims of the social ser• to exist. We must be successful. We shall of alternatives, the extensive use of grant- of the 'two-up/two-down' dwellings that I vices some of which bring back no dividends have to do our sums much more differently aided private improvement of the dwellings, referred to are these: first, their size and shape. to the general public like day centres for the than we do them for the generality of housing and public improvement of the environment, They are often very narrow fronted - as little elderly, while others bring unquantifiable rehabilitation within predominantly residen• facilitated by the moderate density, some such as 3 or 4 m - and have an even narrower back dividends, like youth clubs which it is thought tial zones. There will be more complex, less areas have been transformed. Clearly.and with extension, containing a scullery and possibly keep youth away from crime, but all of which tangible criteria to identify in deciding re• only limited, occasional infill, they will remain a small extra bedroom above. No bathroom; ment, geography or fringe benefit will have Yet the programmes being proposed for are being pressed by a large number of lationships between cost and benefit - in as areas that provide decent housing standards only an outside WC, often shared. These cot• been left out of account. This list will have to inner cities contain projects of many different thoughful people, or deciding what represents true value-for- and encourage on-going private investment tages may have a theoretical capacity of four be reviewed on some sensible and accepted kinds and the policies announced in the White (c) moving into the comparatively new area money. - perhaps for yet another 50/60 years. In fact, or five persons, but their total floor area can be basis to a length that can be accommodated Paper envisage breaking into areas of activity of industrial development, where many worth• some of those areas are regarded by both as little as two-thirds of that we expect for within the available resources. in which local authorities have barely trodden while schemes will already have been tackled HOUSING RENEWAL young and old residents as far more desirable minimum-sized new dwellings. To provide an Now getting value-for-money means spend• in the past. All of these projects have to be by an army of people in the private sector We are all aware that there has been a gigantic and characterful than the brash, new, high inside bathroom and WC - without building ing money where it achieves most good, but weighed one against another if common who can probably do as well as the small swing of the pendulum during the last decade density estates, so often less well located for expensive, space-consuming and sometimes most has to be defined. If two mines produce sense decision-making is to prevail. We can• group under an industrial development officer away from wholesale clearance towards re• urban amenities, education and employment. environmentally disastrous extra back exten• lead and gold you cannot compare their out• not afford to neglect democratic communal in the Town Hall, where there are arguments habilitation. The numbers of outworn or ill- And financial expenditure in those areas, even sions, or providing a very poor internal layout put in tons, without taking into account the decision-making. for initial subsidies in the form of reduced equipped homes improved with the aid of if it had been at the same level as for new - can reduce the four or five person dwelling price of lead and gold. It is what I would call rents or interest-free loans but difficulties in We could be concerned with problems involv• Government grants and procedures operating housing, would have been very good value- to one which, to modern acceptable standards, the apples and pears argument. Where there assessing which projects will really take off ing choices between housing and environ• during that period reached its peak in the for-money; at anything less than these costs will only house two or three. Individually, de• is no market and no price, there is no common once the initial subsidies are withdrawn, but ment and something else perhaps altogether early '70s. At the same time construction of it has been a bargain! pending on existing occupancy, this may be denominator between the criteria. Social where, at least, there should be some rate of much more important. If I could give an new housing, both in the public and the private But unfortunately there are not many areas enough and may be economic. But while economists have tried to find an objective return on the money spent, or example: a typical inner city authority is now sector, fell dramatically from the numerical where success has been so absolute. There recognizing that we now have huge shortages standard, other than price, to measure whether preparing its programme from a collective (d) environmental works, 'cosmetic treatment targets and achievements of the '60s. are others, perhaps physically similar, and of small dwellings, mass concentrations of one set of circumstances leaves people better ideas paper which contains suggestions as of eyesores' too much of which without We also know there were several factors that also declared as General Improvement Areas them in large areas of identical two-up/two- off than some other set of circumstances, but diverse as special types of housing for ex• anything else to back it up, does smack of the precipitated and subsequently sustained that - with similar types of action intended or down cottages is unlikely to be a realistic or so far very few useful rules have been estab- tended families, more social welfare officers, planned orderly withdrawal strategy which pendulum swing: economic restraints; a initiated - but where the downhill trend has socially acceptable solution. 18 lished or even laid down. interpreters, a Caribbean cultural centre and we mentioned and ruled out earlier. new awareness that sweeping clearance barely been disturbed, let alone reversed. And At night, the play of light against the cham• Armed with this strategy you have some sort of the ideas can be ruled out immediately and extended families may have been included in fered stone faces and through the screens and of standard by which to assess projects, not certain of them will in fact be general policy the programme on the grounds that there was brown blinds is particularly successful, which a rigorous mathematical technique but some• suggestions which could modify the strategy a demand for at least 100 units. How many proved a very happy surprise, not entirely thing to go by and one which will produce a in the future, and some of them will be of those actually built to date in response to foreseen. slightly different result from the rigorous general suggestions for projects of a certain this suggestion, have been taken up? How Finally the attic storey with roof terraces on mathematical technique could such be de• kind; more old people's day centres as many dogs have in fact been caught ? Whereas the south and west provides flats for Fellows vised. Any mathematical algorithm that could opposed to a day centre in a particular it was planned to build flats at £12,000 per as well as rooms with an entirely different be envisaged would tend to allocate all ex• location. All the rest have to be analyzed. unit, how many have in fact worked out at character. These are 'roof rooms' with lofty penditure to one category which produced You do not want to spend too long on the £12,000 plus inflation and how many have spaces between low eaves lines, and with most in terms of units of welfare up to a cer• projects which have very little hope of being cost more than that ? spectacular views over the gardens and over tain point at which some other category accepted or in the first instance on those Monitoring of indicators Oxford. became marginal and then expenditure would which are certain to be accepted. You need It is proposed that monitoring of all these be allocated to that second category leaving to concentrate on the.marginal projects, but indicators should go on as soon as the first some categories with nothing. We are likely you don't know which ones these are going year's programme begins to be implemented. to produce a list of projects in practice which to be so one stage in the process is to make a A group of officers will meet regularly to allocates something to all categories of ex• review these matters and a systematic report rough estimate of the cost of all and compare penditure. This could be argued for on the on past projects will be part of the annual the total with the resources available. You can Fig. 36 grounds that we do not know and do not assessment of the current situation in the then rule out a lot of projects and move to the Stone towers provide privacy between even have a rough subjective assessment of inner city areas which officers will put up to next stage which is to concentrate effort adjacent bay windows the marginal contributions to welfare of differ• Partnership Committees and other committees immediately on those left. ent categories of expenditure so it is quite responsible when they begin preparing the When decisions have to be made on the rational to play safe and give something to programme document for the following year, Fig. 37 marginals you need to analyze more fully the all, even on some random basis. But there is rolling forward their three-year inner city Night view; lighting behind random screen certain runners because these also will have probably also an element of political necessity programme for another year. positions creates a varied and changing in this kind of solution. to be justified in the programme document. There are many instances of housing schemes spectacle Money This is a two bites at the cherry approach, and giving grey hairs to architects and quantity St. John's is a building that has to work at a one which local authorities are not very well surveyors and bringing finance committees The next step after determining the strategy number of levels, and which seeks both to geared to following. There is always great to despair with their extra costs while yet is to decide how much money there is to be draw references from Oxford as well as visual reluctance in local authority to produce rough housing contented tenants and becoming spent. There will be a specific sum allocated metaphors from the collegiate tradition. estimates with the danger than one may be part of a wider process of successful improve• under the Urban Aid grant, but this will be It is probably the end of an era of college ex• held responsible for them. Rough estimates of ment. It is hoped that there will be a further subject to a 25% contribution from the local il •«••««••••••••••• tensions of this magnitude, and strangely is cost require rough details of content, and these stage of monitoring not of individual projects • *•••••• authority. The contribution is asked for within 200 yards or so of that first university are often difficult to extract. but of overall achievement of results produced because it is thought that grants normally commission for Somerville's graduate building by all the projects working together. This ::MK::::::::: bring back revenue to the local authority in designed over 20 years ago. Whilst this article Performance indicators latter form of monitoring will go back to the some form directly or indirectly, like increased covers in some detail the design of a single Details of content and performance are im• strategy decisions and see how far they have rates and increased activity in the area, but in i iiriiTlitnin-Ti • n • p m r building, nevertheless I hope it exposes wider portant in the whole process. It is being been achieved, whether there has in fact been any case it is likely that local authorities will ia»ii*««a«!i!fli«iiia> iri ideas and attitudes that have grown up in the emphasized that every project listed in an inner a noticeable improvement in housing or the in effect have their 25% contribution returned I IIUUdllaJIJilllJilLjli intervening years. There has always been a city programme should have as many per• environment overall regardless of how far to them in the form of needs grant under the • • • - • « «* m m a - m m k. m m m m i close relationship between the architecture formance indicators as possible listed against individual projects may have succeeded or settlement of the rate support grant in the t •. iHI i• iiriiiiiimi of our college building and much of our it. If you argue for additional social workers otherwise. One imaginative suggestion is following year. office, laboratory, and industrial work. you must show how many you have at that this sort of monitoring might be assisted Each has nourished the other, and St. John's, The grant may be spent on revenue, recurring present and how they compare with the by a series of before and after photographs perhaps more than any of our work so far, projects or on capital. If any grant is spent on national average per 1000 of population, covering as large an area as possible. reflects this variety of sources - as well as our the former then there is a commitment in generally and in stress areas. If you want a Monitoring will also go a stage further back attitudes, and architectural values, applied in future years which will reduce the amount of 'drop in' centre for youths, you must estimate and look at the change in certain indicators on this event to an historic site. new money available in those years. If it is how many are likely to use it and what class of a higher level of generality, at the kind of spent on capital works then the revenue youths over what area you expect it to cater things which study teams used to measure consequences in future years have to be for. Whereas we meet all the difficulties of malaise in the Inner City - crime, vandalism, assessed. These consequences are more likely comparing unlike with unlike which have poor health, unemployment and low educa• to be expenditure than income, and where been described in the paragraphs above, when tional standards. local authorities are now spending 20% of we try to decide whether a social worker is their recurrent funds on servicing debt they worth more than a dog catcher, there must Measurement of achievement are becoming increasingly anxious to avoid nevertheless be some level of dealing with You measure achievement for the purpose of capital works which may generate future social service referrals per week and some educational standards not in expenditure on expenditure and hence there is a further level of performance in terms of dogs caught new classrooms nor on pupil/teacher ratios argument for moving towards the economic per week which would positively rule one out but in terms of academic attainment and 'O' development side of urban renewal. against the other. and 'A' level passes. These things have to be It is unlikely that the Department of the The National Building Agency has been pro• measured in the long term. The programmes Environment will lay down revenue/capital ducing a management model to define the now being prepared will be implemented in ratios for expenditure of Urban Aid grant, but activities which have to be gone through in 1 979/80 and any buildings contained in them they will have to watch how the totals order to prepare and monitor an Inner City will not be completed until 1980/81 or after. between all authorities work out and they may Programme. The first classrooms built in response to the have to exercise some control in the future. present policies will not open their doors to Other financial resources will be available It becomes apparent from the model that the pupils for three or four years and the brighter from the Locally Determined Sector alloca• time available for the preparation of the first interior behind those doors will not have its tion which is not a grant but an authorization draft of the programme will be exceedingly effect on 'O' level achievements of those to raise loans. tight and although we have described above a two-stage process of rough estimates re• pupils until some years after that. Bending of main programmes fined later it is possible that yet a third itera• If there are improvements it will be hard to Then over and above these and other minor tion will be required because of the lack of demonstrate that they would not have taken sources of funds it is likely that as much time available to finalize the second stage place anyway through other influences. If again will be allocated to the inner cities satisfactorily. After the first draft of the pro• there is no improvement it will be possible to through the process described as the bending gramme has been produced and submitted to argue that things could have been actually of main programmes, the allocation by central the Department of the Environment for con• worse if our policies had not been imple• and local government of an increased propor• sideration, it will be desirable to have another mented. However, difficult as it may be to tion of money available under for instance, run through the projects, checking their assess these things they will be the real education or housing, to inner city areas. cost estimates and the other measurements of measure of improvement and it is only through Where the local authority does the bending what they are supposed to achieve, before the these measures in the distant future that we there is no overall increase in the funds avail• programme is finalized in January to March will know the real value for money achieved able to it. Where the bending is done by immediately before the beginning of the by our policies for the Inner City. central government then the local authority financial year. All this will require a consider• Clearly we must have faith. We must have with the inner city problem is that much able amount of effort particularly by the faith in ourselves to deal sensibly with this better off at the expense either of other local quantity surveyors and planning teams. most complex problem. And I do believe that we can be successful provided we are not too 1 authorities or of other categories of govern• Once you have all these indicators recorded ment expenditure. you usethem not only to decide which projects intoxicated by the technological possibilities are to be included in the programme, you use of this last quarter of this century which appear The next step is to look at all the ideas and them to see that you are getting value-for- to ignore the need for balanced human bids which have been submitted for the inner money in another sense in actual performance judgement exercised in the best interests of city programme which has to be drawn up Main contractor: Johnson & Bailey as the projects are implemented. Housing for our community. 1 (Photos: Arup Associates) each year by the end of the summer. Certain Koralek, of Ahrends, Burton and Koralek, was 1967, and to which the new Arts Building Arts and Social considered more sympathetic to the aims of bears a strong affinity, being clad in the same the college, whose stated requirements were light cream Wicklow granite), to the south Sciences Building 'a design involving one or two interlinked by Nassau Street and its belt of flanking trees, new squares, of elegant proportions, whose and to the west by the Provost's House and Trinity College, style should be consistent with the historical garden. interest and architectural value of the site'. The outline brief and the site posed, in the Dublin Emphasis was placed on the desirability of architects' own words 'the problem of con­ retaining a substantial area of lawn immedi­ centrating a large amount of accommodation ately to the south of the old library, and of on a restricted site, further restricted by the ARCHITECTS: preserving as many trees as possible. Pedes­ desire to use the minimum site area without AHRENDS, BURTON AND KORALEK trian access to Nassau Street, exclusion of making a high building, and the intention to traffic noise, and flexibility of accommodation form a well proportioned new square on the were essential requirements of the building. site of the Fellows' Garden. a square com­ Peter Ryalls In addition the architect was urged 'to seek parable in scale to the older squares in Col­ to provide facilities for staff and students lege and completing the pattern of these During the years 1938 to 1958 the number which would give the Faculties, Schools and squares, symmetrically about the central axis of students at Trinity College increased slowly Departments concerned a new sense of of the college·. from 1500 to 2000. Since that time the student identity and community, yet preserve and The trapezoidal shape of the site created the population has more than doubled, and in develop those aspects of the present arrange­ further problem of reconciliation between the 1966 the College commissioned a develop­ ments that encourage a sense of membership rectilinear forms of the buildings and squares ment study of the whole of the site. That of a college with a rich diversity of activities·. of the College, and the oblique angle of the development plan determined the pattern of The site (Fig. 1) lies in the Fellows' Garden, line of Nassau Street on the southern bound­ growth for the College and established the a fine and relatively restricted area of garden ary. The apparent mass of the building and its design parameters for the new Arts Building. on the southern edge of the College. It is sur­ height had to be in harmony with both the old Ideas were then sought from architects, and rounded to the north-east by the new library and new libraries facing onto the new Fellows' of the two schemes submitted, that of Paul {also designed by ABK and completed in Square (Fig. 2).

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Fig.1 Site plan (Reproduced by courtesy of the architects)

Fig. 2 Section showing relationship of the new building to the old and new libraries (Reproduced by courtesy of the architects) 20 .1.1 > \1 1^1 —— . 1

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Fig. 4 Stepped north facade looking onto the new Fellows' Square (Photo: Antoine Raffoul)

Attempts were made to reduce the apparent sides collapsed quite quickly. Allowance was height by stepping the north face, in order to therefore made in the Bills for pumping the open up again the reduced Fellows' Square. site, if necessary. Individual pad footings The success of this can be seen clearly in Figs. were blinded immediately formation level was 4, 5 and 6. The roof line was kept down to that reached. The lower ground floor slab was of the new library, and the building was laid on 200 mm of no-fines concrete to avoid squeezed down, the ground floor being now impeding ground water flow, and the slab and Fig. 31 Fig. 33 below the level of Fellows' Square; the per• associated retaining walls were designed as The world within a world' Section showing relationships between missible 'squeezing' being constrained by the watertight to a level above expected flood structure, glazing, screens and interior high water table. Apparent height has also levels. During excavation, water flow was furnishings been reduced by earth banking. 'Remoulding' found to be far less of a problem than had caused the 400 seat lecture theatre (Fig. 8), been feared. Once the local water table had which projects clearly at the top of Fig. 3, to be been drawn down, the flow was easily con• tucked under the general accommodation, to tained, to the relief of all concerned. such good effect that its roof (extreme right The Edmund Burke Theatre of Fig. 4) and the upper part of its west flank The roof of the Edmund Burke Theatre is wall, are barely noticeable behind the bank generally of reinforced concrete beam and and shrubbery of Figs. 6 and 7. slab construction. Overall height of the theatre When trial pits were dug for the site investiga• had to be kept to the minimum; the roof level tion the inflow of water was such that pit had to be kept down to improve the open III!! 1 -4' V V V ILV-lLVmLvWli V V V 1' P"F"

tuni IUHUUHI t' IUHHHHHIII i v Fig. 5 jixuLmnLmm |i ,i 11 ,i |i ,i ,i y mm -U-U ii ii ii mi ii ti ii ti ti ii »i u^uuuij North face: the clear sloping glazing WTrirTjpqp V l V I'll I iOUUU: P forms the roof to the double-storey library STEP (Photo: Antoine Raffoul) lUHHHHHnrrtq -1HUI tl ,UUI II11 ll tLjJ4i4fJ Fig. 3 Models showing evolution of the design U li.li ii ii n ii pq from first planning approval (top) to building as built (bottom) (Photo: Antoine Raffoul) i : : in Hi i: l-l-t l-V- Fig. 32 Model of a 'set' unit IVl'VVVVV t:j:|«:i! V Wi-l-l'V The building form, for which planning per• mission was first granted in 1972, is shown at the head of Fig. 3. An appeal and public enquiry concerning the siting of the building \ in relation to Nassau Street was held and a revised building line moved the building about 14 m to the north, thus reducing the Fellows' I Square, and disrupting the relationship of the J new building with its existing companions. Paul Koralek and Patrick Stubbings con• sidered that the building in its revised location was unacceptable and they embarked upon successive strenuous and exhaustive exer• cises to remould and adapt the fixed volume of the building to a more confined setting. These are shown progressively in Fig. 3. The building originally approved is at the top, the alternatives and modifications progress down• wards, arriving at the building as built at the bottom. 21 Fig. 6 West face, with Georgian university 4 buildings in the background (Photo: Antoine Raffoul) i

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Fig. 28 Reflections of old and new 71 Fig. 27 top The main college bar faces south onto the quadrangle

Fig. 29 above Upper (soft) bar (cill to colonnade is above eye level) with view over gardens

• Fig. 30 left Model of main (hard) bar

36 1 I ill Y 5_ Circulation All staircases, ground floor common rooms Fig. 7 and bars, have direct access from a single West face, showing the flank wall of the colonnade. This colonnade faces towards the 400-seat lecture theatre unobtrusively tucked old college buildings, so that it is not only almost below ground and beneath the visibly part of the circulation system of the glazed accommodation in the middle college, but also helps to tie and identify the foreground new buildings with the old. It links the porter's (Photo: Antoine Raffoul) lodge at one end to the east quadrangle and the new squash court buildings and 'sets' at the other, with access to St. John's main garden. In the design of this most important ii in it aspect of the buildings we wanted particu• larly to invite curiosity and search. Only by walking through the buildings and experienc• ing them did we wish them slowly to be fully revealed and then naturally used. This, of Fig. 8 (below) course, is very much within the tradition of Interior of the main lecture theatre the pattern of Oxford colleges, and bearing in (Photo: Antoine Raffoul) mind the size of the new buildings, one which we wished to exploit. aspect of New Fellows' Garden, and the floor had to be kept up out of the water. The solution adopted was to span reinforced con• crete beams from back to front and to support these on a fabricated steel beam, 1.5 m deep Fig. 23 above spanning 18 m transversely, located directly South west paved court and end pavilion above the lecturers' dais. The beam supports, in addition, one storey of professors' accom• modation. Service ducts passing from front to rear between the concrete beams pierce the steel beam very significantly and neces• sitated the use of heavy plating and stiffening. The beam was concrete-cased, weighed approximately 20 tonnes and was brought to site in three sections. Stepping of the north face of the building has resulted in the crea• Fig. 24 left tion of peaceful courtyards (Figs. 9 and 10) Main colonnade from which all staircases around which the rooms of professors and and commonrooms have access lecturers are clustered. The building volume, which was displaced by stepping the north face, moved above the lecture theatres on the south face, and the new south side of the building follows the oblique line of Nassau Street, (Fig. 11).

Fig. 10 (below) A different view (Photo: Antoine Raffoul)

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Figs. 25 and 26 The design of the circulation within the Fig. 9 Oxford tradition intends to stimulate curiosity and invite search One of the enclosed, elevated courtyards (Photo: Antoine Raffoul)

Fig. 11 Model showing the varying arrangement of walls on the south face (Photo: John Donat)

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23 I Fig. 13 (below) 45° chamfered corners of walls are a strong feature of the bu Iding, both externally and internally (Photo: Antoine Raffoul)

Fig. 12 The south face, faceted, and cream granite clad (Photo: Antoine Raffoul)

Fig. 14 The east face. The sharpness, clarity of line and meticulous detailing shown here are characteristic (Photo: Antoine Raffoul)

The staggered, cream, granite-clad faces pro• vide both shelter to the occupants from the noise of Nassau Street, and a delight of wand• ering walls and peeping windows, glimpsed through the curtain of trees to the passer by (Figs. 12, 13 and 14). Whereas the granite cladding to the new library is 100 mm thick, that of the Arts Building from the same source, due to finan• cial stringency, is only 35 mm. This created problems of detailing, of both stones and supports, particularly where a splay corner stone follows a wall which turns through 45°. In order to make the stone appear continuous around a corner, it was mitred and glued at the factory. Design of suitable supports for such a stone which allows for vertical shor• tening of a four storey high wall, thermal ex• pansion of the granite on a south aspect, and variation of wall location from the theoretical, produced a fine exercise in tolerances, hori• zontal, vertical and personal. T*r>>ugbiHy*G«fcry Within, use of applied finishes has been kept to a minimum, and the white concrete cof• fered ceilings and painted block partitions are shown at the entrance to the Douglas Hyde Gallery, (Fig. 15).

Fig. 15 Interior surfaces showing the decorative use of a lignacite wall, and exposed coffered white concrete slab soffit as a ceiling (Photo: Antoine Raffoul) Second scale traverse the coffered ceiling of the upper level, (Fig. 20). The second scale is the structural one. The Fig. 16 precast 'H' frames define the enclosed spaces The entrance hall, The exhibition hall, (Fig. 21) is of double within the pavilions. using air conditioning storey height. Demountable exhibition walls ducts as sculpture shown at the left of the illustration are Third scale Photo: Antoine Raffoul) clamped to stainless steel wires suspended The third is the element of the cladding itself. from the roof and bolted into the floor. Sockets The stone shields are detailed within the are permanently fixed in floor and ceiling on a main frames, and the metal sections of the •hi ~Lm grid pattern, and wires may be strung as re• large sliding aluminium windows become the quired to form hanging walls. : equivalent of moldings. Construction began in 1974, and the College moved in and entered upon the first academic Fourth scale I- year, in October 1978. With accommodation The fourth scale is formed by all that which for 3000 students the New Arts Building is fits within the framed enclosures, and is con• humming with activity. structed largely of wood. This is the domestic, The architects have said that 'the design aims and the smallest scale, and is designed to be to provide a coherent visual order which is distinct and separate, but also a smaller re• directly related to the functional order of the statement of the same essential idea. This is the building and is also an expression of its con• scale at which the building is handled, struction. This approach extends into the in• touched and used. terior design and furnishing of the building There is, in this way, a system by which the which is seen as a direct extension of the various elements of the building are not only architecture. The Arts Building is designed in related, but are also visibly interdependent. the belief that the quality of the visual en• Starting from the smallest scale, and working vironment matters and that it has a part to up to the largest. play in the educational function of the building'. The building was officially opened on 11 December 1978 by the President of Ireland, Dr Hillery. At that ceremony, at the reception which followed and at the evening party spon• sored by the design team, nothing but praise was expressed. Even the press and the stu• Fig. 17 dents themselves are very pleased with what The entrance hall, coffered slabs must be described as a very successful con• and cruciform columns clusion to 10 years of committed work by all (Photo: Antoine Raffoul) concerned.

Fig. 18 u Acknowledgments The two-level library and north light glazing (Photo: Antoine Raffoul) Architects Ahrends Burton and Koralek Fig. 19 Quantity surveyors 'Time for reflection' Patterson Kempster and Shortall (Photo: Antoine Raffoul) M & E engineers Varming Mulcahy Reilly Associates Acoustics consultants m Kenneth Shearer and Associates Landscaping Lanning Roper n Main contractor John Sisk and Son Ltd.

Fig. 19 top left The new college entrance from the Exposed services form a feature in the entrance Fig. 20 Fig. 21 Lamb & Flag Passage as seen from the hall, (Figs. 16 and 17) with a painted rainwater Brightly painted air ducts are used as a The double storey exhibition hall, and gallery new quadrangle pipe running alongside the cruciform-shaped feature (Photo: Antoine Raffoul) (Photo: Antoine Raffoul) columns.

The coffered floors are 400 mm overall depth, but the carefully detailed rebates 50 mm x Fig. 20 above 50 mm on the soffit of the rib reduced this. New squash courts with 'sets' over, Spans of 11.25 m x 8.55 m indicated a very viewed from the Robert Graves Room flexible floor, and precautions were taken to reduce relative deflections during construc• tion by loading two floors with stacked block- work before permitting block wall construc• — •ll|!||iwi tion to commence on the lower floor. This restriction was maintained throughout. Con• I' siderable difficulty was experienced in Em»7% achieving and maintaining the high standard of soffit finish required. Formwork arrises of the rebates deteriorated rapidly; coffers would stubbornly warp, and carefully taped joints i would sometimes leak. The results show, however, that the efforts made by all con• cerned to achieve a high quality 'as struck' Fig. 21 finish in white concrete have been successful. A garden building • typical outlook The library (Figs. 18, 19 and 20) is on two levels, and the sloping north-facing, glazed I roof provides illumination to both levels. The Fig. 22 right lower level, to the right of Fig. 18, projects The elements from which the building is made under Fellows' Square. Air supply ducts boldly 25 At the start of excavation there will be equal phragm walls will progressively yield passively The British Library: and opposite pressures acting on each face of as the excavation proceeds and to take the diaphragm wall. account of this requires a non-linear model. a computer model As each floor level is excavated, the pressure While linear elastic theory is reasonably appli• due to that storey height of soil is removed. cable to the undrained condition when the for London clay This will cause increased horizontal compres• high bulk modulus of water effectively main• sion in the soil inside the wall below the ex• tains the soil at constant volume, in the ARCHITECTS: cavated level and in the floor slabs already drained case, the change in volume of the COLIN ST. JOHN WILSON & constructed, resulting in inward movement of clay matrix results in a change of stiffness and PARTNERS the wall and a decrease in pressure outside this introduces a high degree of material non- the wall. linearity. Long-term predictions have there• David Croft While the inward movement of the wall will be fore in the past been restricted to simple calcu• Brian Simpson sufficient to allow an active state to develop lations of overall consolidation settlement in the fill above, the strains within the London and heave, etc. Nick O'Riordan Clay itself will not be sufficient to reduce the Although the above factors are not of over• stresses to the active pressure values. riding importance, it was thought that they must be considered since analysis for the Introduction Inside the excavation, the progressive removal of soil will cause a reduction in the available British Library requires an extrapolation The British Library project has already been passive resistance of the material not yet beyond the experience gained from other, but described in general terms in the last issue of excavated so that, as the horizontal stresses significantly smaller, excavations. The non• The Arup Journal. The structure, which is to increase, this material will tend to yield linear elastic-plastic model of London Clay be built on a site in Euston Road adjacent to passively. (called Model LC) has therefore been de• St. Pancras Station, will consist of up to seven veloped to enable these effects to be quanti• The movements and changes in stress will be storeys above ground and will have areas of fied and their importance assessed. two, three and four basements. The deepest determined by the stress/strain characteristics basements will be about 100 m square and of the different materials. They will also be Non-linear effects observed in require excavation to roughly 24 m below time-dependent as discussed below. London Clay ground level and 4 m into the Woolwich and On completion of the structure, the horizontal It is well known that the results of laboratory Reading Beds. At about the same level, the pressure on the outside of the wall will be stiffness tests are difficult to correlate with tunnels of the Northern Line and Victoria Line somewhere between the original pressure stiffnesses back-figured from measurements will pass between the areas of deep basement. (the pressure at rest) and a minimum value of full scale structures. Typically the ratio

Further London Transport and British Rail which is equivalent to the active pressure. Eu/Cu is found in laboratory triaxial tests to be tunnels run just outside the site boundaries The reduction in horizontal pressure (total about 100, but in the field to be between 500 at shallow depth. stress) in the soil outside the wall and the and 10006. Marsland78 has claimed that In this article, the problems associated with corresponding horizontal expansion of the stiffnesses measured in large (865 mm) diame• the design and analysis of the deep basements clay causes a reduction in the pore water ter plate bearing tests are fairly close to the are discussed. The size of these basements is pressure which can become a suction (nega• back-figured values. In Fig. 1 the comparison tive pore water pressure). between triaxial, plate test and large scale such that their design will involve a substan• 5 tial extrapolation beyond the experience This drop in pressure will cause water to flow results is shown, reproduced from St. John . gained from other previous excavations and into the area from other areas where the water It is commonly stated that the reasons for the much lower stiffnesses measured in the labo• it is therefore considered that the best com• pressure is higher. The rate of flow will depend Fig. 17 above Fig. 18 ratory are sample disturbance (especially the putational methods available should be used on the permeability of the clay which is pri• New quadrangle with lowered garden, whose wall First floor plan. 'Sets' are planned on the sou opening of fissures) and bedding of the in the justification of the design. To this end a marily determined by the presence of connec• provides a visual base for the old building bedsitting rooms on the east and north special finite element model for London Clay ting sand lenses and open fissures. The situa• samples in the test apparatus. However, the results of very careful laboratory work show has been developed and will be used in the tion where the change in pressure occurs that remarkably consistent and repeatable analysis. In order to subject the theory to rapidly compared to the rate at which water results can be obtained. Atkinson* prepared criticism from across the civil engineering can flow in is called the 'undrained' condition. 2 triaxial specimens from block samplesobtained profession, a paper describing this model has The increase in water pressure after the struc• at the Barbican site. He found that for strains been prepared and submitted for publication. ture is complete will cause increased com• up to about 1% the material behaviour This article contains an abbreviated descrip• pression and shortening in the basement floor appeared to be anisotropic elastic for a large tion of the model itself and the methods used slabs and inward movement of the wall. variety of stress paths. For a given initial stress to calibrate it. The floor slabs shorten elastically as the com• state, the behaviour was linear up to 1 % shear pression in them increases. In addition, long- strain. Design of the retaining walls term shrinkage and creep will allow further In order to limit ground movements, it is pro• inward movement of the wall to take place. In contrast to the consistency found by posed to construct the basements by a It is apparent from the above description that Atkinson, it would be expected that the effects scheme similar to that used for the New the deformation of the soil and structure and of sample disturbance and bedding would be Palace Yard Underground Car Park3. Dia• the stresses induced in them will be highly fairly random. It therefore seems appropriate phragm walls will be constructed around the indeterminate and will depend on the con• to investigate other reasons for the consis• site boundaries and these will be supported struction sequence and timing and also on tently low stiffnesses measured in the labora• by floor slabs. Excavation will proceed by therelative stiffnessesof thedifferent materials. tory. mining beneath successive floor slabs. The In order to design the diaphragm walls and to Many workers, including Lewin'0, Som" and slabs will be supported by piles and columns predict the likely movements of the tunnels Atkinson have reported 'threshold effects' in placed before excavation is started. and surrounding buildings, it is necessary to London Clay and other soils. In some of his Generally soil-retaining structures can be de• understand not only the deformation be• oedometer tests, Som held samples at constant signed using the standard Rankine or wedge haviour of the structure, but also of the London stress for many days and then recorded excep• methods. These, however, assume that the Clay and of the underlying strata. A number of tionally high stiffness as the next small incre• limiting active and/or passive states are approximate Young's Moduli for these are ment of strain was applied. Lewin reported a attained and give no information on the im• available from various back-analyses of deep similar high stiffness when the direction of plied strains and movements. To decide excavations in London Clay (Cole and Bur- straining was changed. It is therefore useful 5 whether such approaches are valid in this land* and St. John ),and these can be used in to compare the magnitudes of strains relating case it is worthwhile to consider the sequence finite element and other computations. How• to various loading situations as follows: of events that will occur in the soil/structure ever, these previous back-analyses have The stiffness parameters reported in laboratory system during and after the construction of assumed linear elastic soil behaviour and, tests are usually based on a range of shear the deep basements as follows: although a fair degree of agreement with field strain up to about 1%. Atkinson states that The construction of the diaphragm wall will measurements has been obtained, a number his measurements at strains of less than 0.2% reduce the magnitude of the horizontal stres• of problems have been noted as follows: are not reliable and therefore quotes Young's ses in the clay causing inward movement of It has been difficult to achieve good pre• Moduli based on tangent moduli at 0.25% the surrounding soil. However, as the wall is dictions of both the movements of diaphragm strain. walls and of points outside the excavation constructed in short lengths, the effects will In Fig. 2, the results of 'typical' plate bearing from the same analysis. be localized and the overall reduction in tests reported by Marsland are reproduced. pressure will probably not be great. In order to obtain satisfactory results, the An approximate scale for the average shear The bored piling operation will result in in• stiffnesses assumed for the London Clay have strains occurring within one diameter beneath ward movement of the clay in each pile shaft. to be very much greater than those measured the plate has been added to the horizontal These movements will be associated with in laboratory tests. axis. At very small strains (<0.1%), the tan• overall inward movements of the diaphragm gent modulus is similar in magnitude to the 26 wall and surface settlement within the site. It is apparent that the material inside the dia• values found from back-analysis (Eu/Cu = Fig. 13 Material that, due to creep effects, the centre of the KYS will move to coincide with a new strain Entry to colonnade Oxford was built largely of Headington stone, t MN m

which gave the old city its uniquely beautiful " ?! hi HI 'I I1C state if that state ismaintainedfor a long period it: io; ?I • (I 40 150 160 ' It colour. Many of the older buildings have now i I I of time. This could model the threshold effects been refaced with Clipshan because the after time lapses, reported by Som. quarry ran out, and the weathering properties \ The work of St. John (Fig. 1) suggests that of Headington were sadly less durable than Vertical msil the ratio of horizontal to vertical stiffness may la sit those of the stones which are now replacing " OS be similar at very small strains to that found

it. We wanted as close a match to the original Hor izonta si ti. in laboratory tests at larger strains. All the stone as possible. Clipshan is too yellow, and IPSIS stiffnesses used for the small strain range have Portland too white, and neither have the subtle ' 10 • been assumed to be proportional to those warmth of Headington. A quarry near Paris obtained from laboratory test results (i.e. provided the nearest that we could find. It the stiffnesses during 'intermediate' behavi• had been used on Chichester Cathedral, and Fig. 15 below our). had many of the qualities of Caen stone. Sur• 015 • Precast 'H' frame prisingly, in spite of transport, the costs were Intermediate strains (outside the KYS) more favourable than for an equivalent Eng• The strains during 'intermediate' behaviour lish stone, largely due to highly mechanized i ... represent the range normally measured in quarrying techniques. laboratory tests. Atkinson* reported that The precast concrete 'H' and half 'H' frames London Clay behaved like an anisotropic were tooled and used a Baladon aggregate elastic material in this range of strain, except 0 ?'. similar to our previous college buildings. The that strains were not necessarily recoverable. attic storey and roof was clad in lead. The Thus the behaviour has the appearance of problem of weathering was very carefully elasticity but is to some extent plastic - hence considered in the design, particularly in view » 030 the term 'intermediate'. of a proposed lifespan of 400 years. The stiffness moduli adopted have been chosen to fit Atkinson's data with the assump• Scale tion that all intermediate stiffnesses are pro• As well as four faces, there are four scales to £ 035 portional to (s + e'eotep') (that is, the mean St. John's. The major one is the organization normal stress in the plane of deformation, of the plan into 'pavilions' and link towers. with an additional term to take account of This arrangement allows flexibility in section cohesion). This assumption ensures that both as well as in plan. Thus in section the terminal Fig. 14 left stiffness and strength are compatible as block is six feet lower than the porter's lodge Stone and wood: typical detail limiting conditions are reached. and the angle between the two wings is L oca no Type ol Test S. u.i e adjusted to suit the site. 0 45 s t Back analysis ol COBS and Plastic strains (approaching the limiting shear In this way, almost one storey in height is lost, Bnttanic House ground movement Builanc! (1972J strength) and, as seen from over the old wall, is of com• New Palace Yard I St Joh parable height to the Canterbury quadrangle 'MCA -Tin. I 119751 It has been found that the curve shown in Hyde Park which faces the main garden. End and corner 0 SO Settlement Record? Hooper (19741 Fig. 5 can be used as a 'state boundary curve': Commercial Unton Fig. 16 below pavilions are square, cheating the eye to be• 19/? that is a curve separating attainable stress/ Chelsea Pl.rte res'. Marsland '1971ai Site plan with ground floor lieve that the others, which are larger, are the strain states from those that cannot be attained. Hendon 1..., Mars,and '1971b same size. This visual deceit makes the build• This curve takes the form of the normalized '. ss ing look smaller than in fact it is. shear stress F plotted against 'total plastic

shear strain' yp:ie the sum of all incremental plastic shear strains, irrespective of direction. If a flow rule is assumed, it can be shown that Fig. 1 this is uniquely related to the plastic volu•

Variation of E (undrained) with mean effective stress; after St. John (1975) metric strain vp. Thus Vp is a reasonable direc• tionless parameter which with suitable mani• pulation and choice of origin, can be related to the voids ratio. 1000). As shear strains increase beyond 0.5%, It has also been demonstrated that the stiff• A modified form of the Cam-clay flow rule however, the secant modulus approaches ness of most soils increases with the mean (Schofield and Wroth") has been found to fit that measured in the laboratory. effective stress: this feature is included in Atkinson's data when used in conjunction with The shear strains occurring behind a retaining Model LC. the state curve as follows:

wall are shown in Fig. 3. For a movement of Svp 0.2% of the wall height (an upper bound for Description of the model = sintp' (F„ - F)

retaining walls in firm soil according to Syp 2 Model LC relates increments of effective Peck' ),the shear strain in the ground exceeds stress to increments of strain, given the current where F = t/(s sintp' + e'eos

The principal axes of plastic strain increment (Ex + £y, EX - Ev. rXV). (e« + Sy. ex - e¥, fxy) space. Its radius = e

0 8 0

0 6 _

o Pravtoua atatea /E/C = 300 u U • Currant state % Kmamatic ynWd I rises I ridui C„ )

0 4 o //// Id Idl

0 2 ' //// /

n 0-5 10 t-S Settlement/plate diameter (O/B)% A* a* X .¥ •'• componwitt of atrain I 0 5 Shear Strain^ I -E ^ -StiftitefM ina.rJa KYS

Note Values of C were obtained from the plate tests and E <( - Stirfnaas ouUffd* KYS are probabiy about 30% lower than laboratory values

Assumptions qu = 10 C (includes allowance for depth]

E = g'j B(1-VJ) V. 0 4

Fig. 2 Fig. 4 Results of 865 mm diameter plate-bearing The kinematic yield surface effect tests on London Clay; after Marsland (1 971)

Fig. 9 above

'Face' to the new quadrangle

Fig. 10 left 1 \ jnioading Reloading The outer 'face' and outer wall to th college, next to the new entrance Fig. 12 right

4 e 8 The silhouette - the fifth 'face'

Plastic shear strain yt %

7 sK { s sin 4 • c COB • ) (rr, •

2 («r,-»',l 2 Si-tM' *ti*m carton'* to. • mturtiuxi wall d'«pt»C»m«nt 0 2 O* •• Haior and minor principal stfectivs stresses •>•

I 2 5% Fig. 11 below Fig. 3 Fig. 5 View from President's garden with Strain contours around an excavation The state boundary curve new screen wall and summer house

Intermediate range Implementation into elastic/intermediate state and the plastic The parameters of anisotropic elasticity are the finite element stage. adopted. program Fully drained behaviour can be modelled by holding pore pressure constant. The un- E' = E'v (s + c' cot

2 c' = 20 kN/m The program is suited to geotechnical prob• compressibility of the pore water. The bulk Adjacent to the site, to the north, is a small

Typical vertical stress Ovsti/m'

(a) SWELLING FOLLOWED BY CONSOLIDATION

Normalized Stress <5v/0»'|ma»

1 ~ —— Measured

L—J Compulse!

"J »0

1 2 3 Typical vertical suees Ov'hN/m'

Horizontal compression % b) CONSOLIDATION FOLLOWED BY SWELLING. Four faces porter's lodge off the Lamb and Flag Pas• Fig. 7 There are four faces to the design of St. sage, and this facade also forms the outer The urban 'face,' as glimpsed from St. Giles John's. The first is glimpsed from St. Giles', wall of the College. There is in a sense also Fig. 6 Fig. 8 and forms a part of the urban scene. The the fifth face - the roofscape and silhouette, Plane strain tests Oedometer tests second appears above the walls of St. John's which had to respect the skyline of Oxford. great 18th century garden, and is seen be• In this case, the organization of the plan tween groups of large trees, as well as from a naturally creates a strongly differentiated set Fig. 8 distance across its open lawns. The third is of forms at roof level, which aim to be com• As seen from St. John's great garden; the elevation to the new quadrangle itself, patible with their collegiate and domestic note that the lowered quadrangle reduces / and finally, there is the new entrance and neighbours. the apparent height /

/ / / 1500 / 3 / VeHical

50 /

1OO0 /

sot.

30 / /

Radia VXI 20 Honzonra 1" stress I Ct'Cumtef ent ial

LL) 10 .wtlemant o

Vertical strain [, % Diam«te*

Measured Pla Radius Ol KYS Computed »iiiwmm«(iic E>21f P»I Computed plane stress •°c: 125 1 too ut

AaiaFmmatfic C, 24 pei 200 »E 11 5O0 u£ giving •36

154E.

Fig. 7 Fig. 9 Triaxial tests Plate bearing tests Comparison with laboratory and field ditions. Up to about 2% vertical strain the The results of the comparison with the plate- tests computations agreed well with measurements. bearing tests reported by Marsland are shown However, no failure was predicted and the in Fig. 9. The measured load/displacement Predictions of the model have been compared shear stress increases slowly. This occurs curve is compared with predictions made •0 i NORTH with the results of plane strain and triaxial because the model is not designed to cope using three different values for the radius of undrained tests carried out by Atkinson. In with situations of significant strain in the the kinematic yield surface (ea). The com• Fig. 6 the computed predictions for two un• circumferential direction. puted load/deflection curve is close to that drained plane strain tests are compared with In Fig. 8 the results of a large number of measured at stresses up to about 80% of Atkinson's results, and a good correlation is oedometer tests have been plotted to a norma• failure stress. Rather better results could be achieved in each case. sinngloorr bedroom lized scale. The results are taken from the achieved using a higher value of Ea= 500 ue, Q I DINING The triaxial test is much more difficult to British Library site investigation and predic• rather than 200 ue. tions from Model LC have been superimposed LOWER COURT model. Two approaches have been tried and Comparison with measured heave onto these plots. In studying these results it is A ] the results are shown in Fig. 7. If plane stress below a deep basement • -T A necessary to compare the gradients of the is assumed, the results agree fairly well with 1 curves in the various ranges of stress. On this May * published measurements of the heave Atkinson's measurements. The failure stress is coFlfege \\ of a basement built over a deep layer of 0 lower and occurs at smaller strain than that basis it can be seen that the computed and t measured results agree fairly well in the stress London Clay. The net unloading after excava• measured, possibly because there is less re• 2 2 tion and construction was about 175 kN/m . MCR COURT striction in the third principal direction than range of major interest, 100 to 400 kN/m . In HAW Unfortunately measurements were not started general, the stiffness of the model is greater <' occurs in the laboratory test. A single finite nd 'V until the end of construction and a complicated 2 FLOOR 3'" FLOOR S ^ element was also tested in axisymmetric con• than that of the soil being tested. • extrapolation is therefore needed to estimate ~ • the total heave which has taken place. The ' more recent readings suggest that about 130 Fig. 2a above mm of heave has occurred in 10 years and Typical layout of 'set' with bedrooms on GARDEN J L that there is no indication that the movement intermediate floor is approaching a limit. A simple program using Model LC was written Fig. 2b to provide a prediction for this problem. The Model of 'set' stair to bedroom final heave was computed to be 228 mm, T v. assuming that the pore water pressure will ft eventually return to its original value. How• t> VI ever, the predictions are extremely sensitive 6 ITofrER COURT £ r Key plan to the pore water pressure distribution, SECTION A A particularly in the upper layers and this Fig. 3 right value reduces to 180 mm even if only a small First scheme: general section and site plan reduction in water pressure is assumed. It would seem that in this case the model will Proposed cat park give a reasonable prediction, although pos• sibly somewhat on the high side. This may be East - west section i i.iii ,i clay contrasted with the tendency to predict too little deformation in the laboratory tests. Back-analyses of excavations in London Clay The excavation for the car park at New Palace Yard has been back-analyzed as part of the calibration procedure for Model LC. Burland I • a and Hancock3 describe the site, together with Undrifground railway the design, construction method and moni• toring of the New Palace Yard excavation. North - south section Figs. 10 and 11 are reproduced from their paper and show a plan and section of the work. St. John* provides further information on the Fig. 10 Fig. 11 (below) excavation process and its effect on the New Palace Yard: general layout New Palace Yard: plan and sections ground.

Original ground ravat 104 Fig. 4 Fig. 5 Final scheme: model of development shown within the context Aerial view of site of existing buildings

ip. iik ilk iik ifk 4tk rri IT*

East-west section North - south section-HH

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66M, Fig. 6a left Fig. 6b MM Facade to 'sets' Facade to bedsitting rooms Vol. 14 No. 1 April 1979 Contents Published by Movement towards axcavatton - » Movement towards excavation » Ove Arup Partnership 0 4 8 12 16 20 24mm THEARUP 13 Fitzroy Street. London. W1 P 6BQ 0 4 8 12 16 20 24 28rt

Editor: Peter Hoggett Art Editor: Desmond Wyeth FSIAD Editorial Assistant: David Brown JOURNAL \s«*»o~2\\\^ stage St. John's College 2 Sir Thomas White Building, by Philip Dowson

Value for money 15 in urban renewal, by Peter Dunican

i // Arts and Social Sciences 20 Computed Wall Movements South Wall movements FINAL STAGE Building, Trinity College, Dublin, (measured) by Peter Ryalls Fig. 12 Fig. 13 Fig. 14 The British Library: 26 New Palace Yard: New Palace Yard: New Palace Yard: a computer model south wall movements computed south wall movements measured final movements computed and measured for London clay, by David Croft, Brian Simpson, and Nick O'Riordan Figs. 12-15 show the comparisons between the measured and computed values for the —•———' deflections of the diaphragm walls and the pore pressures. These results are discussed in detail in Reference 2. The paper also contains a comparison of the site measurements at Neasden Underpass as described by Sillser al" with the results of back-analyses. While the New Palace Yard excavation is best modelled Front cover: Sketch of St. John's by an axisymmetric analysis, Neasden in Back cover: Roof plan of St. John's contrast is nearer to the plane strain case. Model LC gives good correlation in both cases. St. John's was the subject of a limited com• sponse to their review, rethink the problem St. John's College petition, held in 1966, between ACP, Howell from scratch. We gave each other six months. Killick and Partridge, William Whitfield, and The present, more modest design, was the Sir Thomas White ourselves. The brief originally included, on a outcome. The new buildings have 156 sets larger site, a lecture theatre, a science library, and bed-sitting rooms. This effectively Building a swimming pool, married Fellows' flats, a doubled the existing accommodation within special dining room for the governing body, a the college precincts. DESIGNED BY restaurant for the undergraduates, and parking The design of the rooms themselves includes ARUP ASSOCIATES for 170 cars. Both sides of Museum Road were a wide range of size, shape and character. The included within the site. organization of the plan into'staircase-service- Philip Dowson Pore pressures hN/m2 The design for this first scheme was worked links' and pavilions provides for adaptability 220 0 Pore pressure measured at this position Fig. 15 'A world within a world', in the words of the up and presented in 1969. At this point there within the latter to accommodate Fellows' on completion of excavation President of St. John's, or 'a room of one's was a new President, and a developing recog• flats. All new development is now to the New Palace Yard: own', in those of the Principal of Somerville, nition that the initial brief was no longer south of Museum Road, and so within the pore pressures computed and measured sum up the aims behind the design of an wholly relevant. There was a need for a review. natural college precinct. undergraduate room. Rather than tinker with the existing proposals, The combination of the scale of this scheme Conclusions References Geomechanics, Melbourne, 1971 and St. John's new building in Oxford, which was we suggested that the College should re• and the complexity of its brief, with the ex• published in the Proceedings, /, pp. completed last year, combines in many assess its needs in the light of the work that treme vulnerability of its site, presented the The geotechnical problems associated with (1) CROFT, D. D. and RYALLS, P. J. The 180-189. respects a developing set of ideas that can had been done. In the meantime, we would most difficult architectural problem we have the design and analysis of the basement re• British Library. The Arup Journal 13 (4), be traced from our first university commission also go away, lick our wounds, and, in re• ever had to undertake. taining walls have been described. A non• pp 2-6, 1978. (8) MARSLAND, A. Clays subjected to insitu plate tests. Ground Engineering, in 1957 for a graduate building for Somerville linear elastic-plastic model for London Clay, (2) SIMPSON, B., O'RIORDAN, N. J. and 5 (6), pp. 24-26, 29-31, 1972. College. These ideas were developed in a which has been developed, is described and CROFT, D. D.: A computer model for design for some flats for Bracknell New Town, the results of predictions made using this the behaviour of London Clay. Paper (9) ATKINSON, J. H. The deformation of and through later buildings for Corpus Christi model have been compared with measured to be published in Geotechnique June undisturbed London Clay. PhD Thesis, and Trinity Hall Colleges in Cambridge, and values obtained from laboratory and field tests 1979. University of London, 1973. for a further scheme for Somerville. and from instrumented excavations. (3) BUR LAND, J. B. antf HAN COCK, R. J. R. (10) LEWIN, P. I. Stress deformation charac• In the case of St. John's, we had to inject a Model LC is currently being used in the Underground car park at the House of teristics of a saturated soil. MSc Thesis, large new development into one of our his• analyses of the deep basement construction of Commons, London: geotechnical as• University of London, 1970. toric precincts, and whilst it had to fulfil the British Library. At the time of writing this V pects. The Structural Engineer, 55 (2), (11) SOM, N. N. The effect of stress path on today's needs, it had to do so within a very article the base analysis has been completed % .r pp. 87-100, 1977. the deformation and consolidation of sensitive historic context. It is a modern and work is continuing on the various para• London Clay. PhD Thesis, University building, but intends to reflect the mood of -1 metric studies that are required in order to (4) COLE, K. W. and BURLAND, J. B. of London, 1968. Oxford, the character of its surroundings, and assess the sensitivity of the results to the Observations of retaining wall move• to settle into the established pattern of this values of the input data. When these have ments associated with a large excava• (12) PECK, R. B. Deep excavations and medieval city. been completed then appropriate values for tion. Proceedings of the 5th European tunnelling in soft ground. State of Art the final design of the diaphragm walls will be Conference on Soil Mechanics and Report, Proceedings of the 7th Con• Diverse relationships available. It is intended that future articles will Foundation Engineering, Madrid, 1972. ference on Soil Mechanics and Foun• Common to all these buildings, however, is a describe this analysis and will contain pre• Vol. 1. dation Engineering, pp. 225-290. 1969. dicted values for deformations that will be wish to create rooms with a sense of location (5) ST. JOHN, H. D. Field and theoretical (13) SCHOFIELD, A. H. & WROTH, C. P. compared with the values measured during and of generosity, a sense of enclosure and studies of the behaviour of ground Critical state soil mechanics, McGraw- construction. release. A wish to develop a relationship be• around deep excavations in London Hill, 1968. tween the small scale and the large, and be• Clay. PhD Thesis, University of Cam• (14) MAY, J. Heave on a deep basement in tween the manmade and the natural via the bridge. 1975. Credits the London Clay. Conference on Settle• intermediate spaces created between the in• (6) BUTLER, F. G. Heavily over-consoli• ment of Structures, Cambridge. 1974. terior and the exterior areas within these Client: dated clays. Review Paper. Session III of schemes. We aimed to exploit the richness The Department of the Environment (15) SILLS, G. C, BURLAND, J. B. and Conference on Settlement of Structures, and unity that can at once be derived from the Architect: CZECHOWSKI, M. K. Behaviour of an Cambridge. 1974. diverse use of repetitive elements, and the Colin St. John Wilson and Partners anchored diaphragm wall in stiff clay. various strands that can be woven within Services Engineer: (7) MARSLAND, A. Large in situ tests to Proceedings of the 9th International strict disciplines, which can help to identify Fig. 1 Steensen, Varming, Mulcahy and Partners measure the properties of stiff fissured Conference on Soil Mechanics and the 'part' within the 'whole', and so help to Model of the winning scheme - subsequently abandoned Quantity Surveyor: clays. Paper presented at the First Aus• Foundation Engineering, 2, pp. 147-155, create a sense of belonging. Davis, Belfield and Everest tralian-New Zealand Conference on Tokyo 1977. 31 CO THE ARUP JOURNAL in t m

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