ENGINEERS IRELAND N25 NEW ROSS BYPASS
N25 NEW ROSS BYPASS
JOHN T. MURPHY, B.E., C.Eng., F.IEI., H.Dip.M.M., FConsEI. Project Director, Mott MacDonald Ireland
JOE SHINKWIN, B.E., C.Eng., M.IEI., Dip. Mech. Eng. Project Manager, Mott MacDonald Ireland
BAIRBRE MOYNIHAN, B.E., C.Eng., M.IEI. Project Engineer, Mott MacDonald Ireland
Presented to a meeting of the Cork Region of Engineers Ireland
10th April 2018
SYNOPSIS
The N25 New Ross Bypass PPP Scheme involves the construction of approximately 15km of National Route comprising approximately 14km of Dual Carriageway and approximately 1.2km of Single Carriageway and associated works. It also includes an extrados bridge crossing of the River Barrow which will include two main 230m spans and a total length of approx. 900m with a clearance of 36m above high water. This paper describes the development of the current route for the N25 New Ross Bypass including the various phases of route selection and follows the project through the statutory processes. The paper also describes the selection of the chosen bridge type for the River Barrow Crossing. Finally, the paper will outline the tender process and will briefly describe the construction contract and some of the progress to date.
1 MURPHY, SHINKWIN and MOYNIHAN INTRODUCTION Initially, a comprehensive examination FIRST PHASE ROUTE of the constraints in the area was SELECTION The need for a second river crossing undertaken to allow the feasibility and providing a bypass of New Ross has route selection process to begin. The Constraints Study was published in been recognised for a number of years Subsequently, in keeping with “National February 2001. After the constraints and has been identified in the Wexford, Roads Project Management Guidelines had been identified, the first phase of Kilkenny, and New Ross Development March 2000”, a Constraints Report was the Route Selection was undertaken. A Plans. The importance of the N25 Cork prepared gathering together all of the variety of alternative corridors were to Rosslare route has been emphasised known constraints. The Constraints selected for consideration having regard in the National Roads Needs Study, Study identified the following main to traffic performance, road network published in 1998 by the National considerations: connectivity, topography, alignment Roads Authority (NRA now Transport The River Barrow was used in design, constraints identified in the Infrastructure Ireland (TII)), and the connection with both commercial Constraints Study and feedback from National Development Plans (NDP) shipping and recreational/pleasure Public Consultation. 2000-2006 and 2007-2013, as well as craft. The Port of New Ross had the Infrastructure Investment Priorities stated that a second river crossing The principal objective of the Study was 2010-2016, published by the should not interfere with the to identify the best overall solution to the Department of Finance in July 2010. navigation of the River Barrow. different needs of local traffic and The N25 connects Cork at one end to Candidate Special Areas of people in New Ross, and those of long- Rosslare Europort at the other end, Conservation, Proposed National distance high-speed National Primary passing through New Ross. Heritage Areas and rare plant Road traffic. It was thus necessary to species were identified in the study test each logical combination of corridors. In the end 46 alternative road This paper describes the development area. networks (comprising various of the current route for the N25 New A large number of archaeological combinations of twelve different route Ross Bypass including the various sites had been identified in the study corridors; Routes A to L) were tested phases of route selection and follows area with a potential for further sites and evaluated. These are illustrated in the project through the statutory of archaeological or historic value on Figure 1. processes. The bypass includes an detailed inspection. iconic extrados structure crossing the The landscape rises on either side of A new crossing of the River Barrow River Barrow and the paper describes the river with hills and tributary and/or the River Nore in the New Ross the selection of the chosen bridge type valleys forming an undulating area together with a bypass of the town for the River Barrow Bridge. It also countryside. Visual constraints would impose costs on, and produce deals with some of the other structures identified include the scenic river benefits for the community at large. among the other 46 structures on the valley, ridgelines, steep hill sides Such a scheme would be justified if the bypass Finally, the paper will outline the and areas of woodland. The benefits that it produced exceeded their tender process and will briefly describe Wexford Development Plan associated costs and did so by more the construction contract and some of identified views from N30 and N25 to than would be the case for any the progress to date. be preserved or improved. alternative investment of the same funds. The existing N25 route at New Ross The constraints identified assisted in the passes right through the town, crossing development of potential route corridors. The benefits that could arise from a new the River Barrow over O’Hanrahan Issues identified in potential corridors river crossing include: Bridge and travelling along the quays. were examined in further detail at route The N30 to Enniscorthy joins the N25 at selection phase. (i) travel cost savings enjoyed by motor vehicles and their occupants, New Ross and also passes through the town via an inner relief road. These are key commercial and tourist routes. In the event that O’Hanrahan Bridge had to close to traffic, this strategic link would be severely affected forcing traffic to divert through Thomastown, utilising the R700 and the restricted bridge at Ferry Bridge (Mount Garrett Bridge). Delays on both the N25 and N30 routes are common. On the N25 in particular, at peak times queues of several kilometres and delays of up to half an hour are a regular occurrence and the delays can be greater. The existing traffic volumes as well as anticipated growth in traffic indicated that a new bypass and crossing of the river was needed.
CONSTRAINTS STUDY
In March 1999, Mott MacDonald (formerly Ewbank Preece OhEocha) were appointed by Wexford County Council to determine the need for and location of a Second River Crossing & Bypass of New Ross. Fig 1: Combinations of 12 corridors used to establish 46 Alternative Routes. 2 N25 NEW ROSS BYPASS (ii) increased travel opportunities The existing situation showed evidence Options which included a junction with arising from improvement of the of significant problems relating to the the R733 showed better benefits and local road network, N25 traffic through New Ross – in internal rate of return than those (iii) stimulation of the local economy by particular, on both sides of the bridge without a connection. They also increasing its potential to attract and on the quays. While significant provided for better connectivity to New commerce, trade and industry to problems repeatedly existed at Peak Ross and its ports. the area, Hours, the hourly average traffic outputs Of those remaining options with an (iv) positive environmental impacts of also revealed underlying problems. In upstream crossing, i.e. Corridors D, E, the crossing particular, O'Hanrahan Bridge, the Quay F, & G, Corridor D was preferred and (v) Benefits to town in terms of and Bridge Street were virtually at was retained for further consideration. pedestrianisation capacity and North Street had reached Corridors E, F & G had practical, (vi) collision reduction/ savings its maximum working capacity. The traffic/connectivity, and environmental model indicated average hourly traffic difficulties and did not offer a viable The costs that might be associated with speeds of less than 15kph (10mph) on solution to the needs of New Ross and these benefits include: O'Hanrahan Bridge, which indicated the National Primary Route Network. (vii) the capital, land, and property very low speeds during peak hours. Of the remaining options with a acquisition costs of the crossing crossing at Corridor D, the and its associated roadworks, The mathematical model of traffic combination of D with L was preferred (viii) the annual operating and behaviour was used to produce and was retained for further maintenance costs of the crossing, forecasts of New Ross area traffic consideration. Options combining (ix) costs associated with the protection conditions that might be associated with Corridor D with crossings at A, B and of river navigation, each of forty six road networks made up C (i.e. multiple river crossings) all had (x) negative environmental impacts of of various combinations of the route high cost and lower internal rate of the crossing and approach roads. corridors shown in Figure 1. For each return. These were eliminated. network, separate predictions were Of the remaining options, those with a Evaluation Methodology made for a typical hour, for each of the crossing at corridor B were eliminated years 2010 & 2020. These predictions due to difficulties with vertical The 46 scheme options were assessed enabled assessments to be made of the alignment (steep gradients on eastern in terms of their environmental impacts economic benefit, and the traffic and side of the river) and environmental and also having regard to their residual congestion implications of each issues including general fit with the performance in terms of traffic, alternative network. landscape (particularly on the western effectiveness as a bypass, and side of the river). economic performance. A variety of Following the evaluations described crossing types were also considered as above the 46 different options were The options remaining at that stage, appropriate at each river crossing carefully examined with a view to therefore, were as shown in Figure 2. location including high level bridges, eliminating the less favourable options. The remaining five scheme options fixed medium or low level bridges, The reasons for elimination of certain (plus the ’Do-Nothing’) were: opening span medium or low level options range from the existence of a Do-Nothing; bridges, and tunnels. similar option but with better Scheme option 5 (A & J);
performance or environmental Scheme option 15 (C & J); Environmental Assessment of characteristics, to options which do not Scheme option 16 (D, I & L); Different Route Options provide a viable bypass to New Ross or Scheme option 20 (C & K); and satisfy the various requirements. These The alternative alignments were Scheme option 22 (A & K). are summarised as follows: selected to minimise known adverse These options were subjected to more potential environmental impacts where detailed examination. possible. In particular, impact on buildings and on environmentally sensitive areas was considered. An environmental assessment was carried out on each route with regard to its impact on the local environment. This assessment covered the following categories:
Ecology Water Quality and Fisheries Archaeology Landscape Geology and Hydrogeology Recreation / Amenity
Traffic Performance
A traffic survey undertaken in New Ross in 1998 was used as the basis for the traffic analysis as it provided comprehensive information about then current (1998) vehicular trips in the area. This data was used to establish a computerised mathematical traffic model. Fig 2: Route combinations retained for further assessment
3 MURPHY, SHINKWIN and MOYNIHAN SECOND PHASE ROUTE SELECTION
Options on Route A
Up to this stage of the evaluation, Options including Corridor A assumed that the existing N25 road would be widened and converted to dual carriageway. (The results of the traffic modelling described earlier indicated that the option would need to be dual carriageway as far as the point where the N30 branched off). Dualling of the existing road involved significant inherent difficulties from a practical, connectivity, and safety point of view. Such difficulties include control of existing accesses, right hand turns, interaction with local traffic, interaction with present or expected speed limit zones, etc. For these reasons, options involving Corridor A were not preferred. Fig 3: Second Phase Route Selection – final comparison However, following further evaluation and public consultation, it was decided This route option demonstrated to modify Options 5 and 22 and retain On the section from Glenmore to the advantages over J4 under agriculture, them for further consideration. The N25 Wexford Road at Ballymacar air quality, human environment, journey modification would involve paralleling Bridge, the final comparison was length, landscape, alignment/ sections of the route such that the new between Corridors A and C. For the engineering, ecology, noise, water bypass was separate from the existing N30 connection to Corcoran’s Cross the quality/fisheries economics, and the N25 where this was desirable and final comparison was between corridors National Primary Route. feasible. J and K. In the assessment, route A was compared with route C (including its four The Route Selection Report outlining Northern Crossing variations, C1, C3, C4 & C6) and Route the preferred route was published in J was compared with Route K. October 2002. During the course of the evaluation of the Options shown in Figure 2, it The routes were assessed under the PUBLIC CONSULTATION became apparent that the northern following headings: option (Option 16 – D, I, & L) would In September 1999 a preliminary Agriculture carry significantly less traffic on the new consultation brochure was distributed in Air Quality the New Ross Standard and the New bridge (and on the bypass) than either Alignment Ross Echo. The brochure showed some of the downstream crossing options. It Archaeology possibilities together with a blank map was clear that significant amounts of Construction Risk and requested feedback from the public. through traffic, particularly between the Development of Town
N25 Wexford Road and the N25 Ecology Waterford Road, would continue to Economics First Public Consultation travel through the town. In addition, the Geology/ Hydrogeology Between 27th and 29th March 2000, projected traffic remaining on Ground Conditions Wexford County Council and Kilkenny O’Hanrahan Bridge in the future would Human Environment County Council, in association with be in excess of its capacity, indicating Hydraulics Tramore House National Roads Design significant congestion in the town of Journey Length New Ross and perhaps the need for a Landscape Office and Mott MacDonald, held a further new bridge and approach roads National Primary Route public exhibition in New Ross as part of at some stage in the future. Navigation the public consultation process for the Noise New Ross Second River Crossing and While Option 16 is the best of the Traffic Performance Bypass. The exhibition included a upstream bypass options, it would only Underwater Archaeology presentation to a joint meeting of the be an appropriate solution if a Water Quality/ Fisheries local authorities (Wexford Co Co and downstream solution could not be Kilkenny Co Co). The objective of the found. Accordingly, it was decided to The assessment concluded that the event was to stimulate debate and invite focus on the downstream solutions to preferred route from Glenmore to the local community to record their determine the most appropriate second Ballymacar Bridge was C6 as this route views with regard to the route selection river crossing and bypass for New Ross. showed considerable advantages over and river crossing. It was estimated that A4 for air quality, human environment, around 1000 people attended the Options for further consideration journey length, noise, alignment/ exhibition. engineering, construction risk, Minor adjustments were made to the economics, the development of New In excess of 2500 responses to the remaining routes in the light of the Ross Town and the National Primary public consultation were received. The ongoing evaluations, e.g. to the Route. concerns raised in public consultation avoidance of particular impacts. The responses included: study area was divided into 2 The preferred route from Ballymacar subsections. See Fig. 3 Bridge to Corcoran's Cross was K4. Impact on farmlands 4 N25 NEW ROSS BYPASS Impact on cultural and rises in an easterly direction in cutting, information which enabled a detailed archaeological and ecological passing under the disused but not update of the model which was run for heritage abandoned railway line to the top of the Do-Nothing case for 2007 and the Impact on amenity and lifestyle Pink Rock. From Pink Rock the route results compared with actual recorded Devaluation of property crosses the River Barrow to Stokestown traffic counts. The comparison showed in Co. Wexford. From Stokestown the good correlation with a maximum Economic impact on the town of route rises in cutting through difference between modelled flows and New Ross and Environs Landscape, bridging the R733 recorded flows of 9%. Impact on landscape (Arthurstown / Fethard Road) to Noise and air quality impacts on Creakan Lower, then rising in both The 2007 trip matrix was then grown residential areas and farmlands cutting and embankment towards using the NRA document entitled Impact on community Arnestown through Creaken Upper. A “Future Traffic Forecasts 2002 – 2040 to yield trip matrices for 2013 and 2028 Existing HGV traffic in the town. grade separated junction with the R733 which were at that time considered to be provides connectivity with the N25. From Arnestown the route descends to the “year of opening” and the “design Second Public Consultation year” respectively. The model was run Ballymacar Bridge to a roundabout with In November 2001, Wexford County the existing N25 road to Wexford. From for the Do-Nothing and Do-Something Council and Kilkenny County Council, in Ballymacar Bridge the route rises in a networks for these years.
association with Tramore House north easterly direction passing to the The “Design Year” daily traffic volumes Regional Design Office and Mott east of Lacken Hill, then turning in a resulting from this analysis in AADT MacDonald held a public display in New northerly direction through Lacken to vehicles were as follows: Ross. The exhibition consisted of Berkeley. At Berkeley the route swings display boards with details of the in a north easterly direction to a Do With Link scheme. The display outlined the need roundabout at Knockroe to the south of Nothing Scheme for the project, the corridors investigated Corcoran’s Crossroads. At this point the O’Hanrahan Bridge 27,909 12,746 and the horizontal and vertical route connects into the existing N30. It New Southern Bridge (From - 15,173 alignment of the preferred route. was envisaged in the future that this existing N25 to R733) Members of the design team were would connect with the proposed N30 N25 Bypass (From R733 to - 12,188 present throughout the duration of the Moneytucker to New Ross Scheme. Ballymacar Bridge) N30 Bypass (Ballymacar Br. to exhibition to answer questions and - 8,419 provide further information. Road Type Corcoran’s Cross)
PREFERRED ROUTE In 2007, the traffic model was reviewed On the basis of the above traffic flows, and a data collection exercise was and having regard to consistency of The preferred route (Refer to Figure 4) undertaken which included classified cross-section and future proofing, it was commences with a roundabout on the traffic counts and number-plate determined that a dual carriageway was N25 in Glenmore Co. Kilkenny a little registration surveys on the major links required for the first 2 sections, i.e. from north of the existing junction with the old into New Ross. This provided up-to- Glenmore to the R733 to Ballymacar road to New Ross. From here the route date Origin and Destination (O&D) Bridge.
Fig 4: Preferred Route Corridor 5 MURPHY, SHINKWIN and MOYNIHAN For the section of road between The principal commodities handled in Bridge Options Report Ballymacar Bridge and Corcoran’s New Ross are: Following the publication of the Route Cross, the traffic projections indicated a Oil Selection report in 2002, a detailed standard single carriageway. However, Fertiliser examination of the bridge options for the because of the topography, climbing Animal Feedstuffs river crossing was undertaken. Initially, lanes would be required over almost Coal 8 options (see Fig 5) were reviewed 100% of the route, resulting effectively Mineral Ores which included: in three lanes of road width. Having regard to safety and relative costs and Meetings were held with the Port of New i) Haunched Box Girder Bridge landtake, it was recommended that a Ross and other port users to discuss the ii) Cable Stay Bridge – Vertical Tower Dual Carriageway should also be scheme and the crossing of the River iii) Cable Stay Bridge – Inclined adopted for the final section between Barrow. During consultation at Route Tower Ballymacar Bridge and Corcoran’s Selection stage the Port indicated that a iv) Arch – Single Span Cross. The recommended cross- vertical clearance of 36m above mean v) Arch – Single Span with “V” Piers sections were therefore: high water spring tide of the navigation vi) Arch – 3 Span channel would be desirable for a non vii) Extrados Bridge – 2 Pylon Glenmore to R733 (excluding Type 1 Dual opening high level crossing. viii) Extrados Bridge – 3 Pylon new bridge) Carriageway Reduced Type 1 River Barrow Bridge Dual Carriageway N25 Bypass (R733 to Type 2 Dual Ballymacar Br.) Carriageway N30 Bypass (Ballymacar Br. to Type 2 Dual Corcoran’s Cross) Carriageway
Journey Lengths
It was noted that the proposed bypass reduces the journey from Glenmore to Ballymacar Bridge by 3km and the journey from Glenmore to Corcoran’s Cross by 5.7km. There are also considerable time savings for those journeys.
RIVER BARROW CROSSING Barrow Crossing Alternative Types
While various crossing types were considered during the earlier Route Selection stage, the crossing type for Route C was a high level bridge due to it’s location.
Port of New Ross
New Ross port, sited some 32km from the sea, is managed by the New Ross Port Company. A capital dredging programme in 1999 deepened the approach channel allowing the port to accommodate vessels of 6000 dead weight tonnage (DWT). A railway swing bridge is in operation downstream of the port at the confluence of the rivers Barrow and Suir. Upstream of this bridge overhead ESB cables at Ferry Point limits clearance to 36m above mean high water spring tide. Port facilities are located on both sides of the River Barrow at New Ross. Two facilities on the west side, located at Raheen and Rosbercon, are owned by Stafford Shipping and handle various dry bulk commodities. Two fixed jetties on the east side, located at the Harbour Office and Marshmeadows, are owned by New Ross Port Company and handle liquids, dry bulks and oil products. A floating pontoon, located at Stokestown, is owned by Stokestown Port Services and handles a range of dry bulk commodities. Fig 5: Initial Bridge Options
6 N25 NEW ROSS BYPASS Following the initial review, four of the found to be adequate to accommodate Setting options were selected to undergo a the construction depth of the deck for all more detailed analysis with a view to options except the haunched box girder, The proposed bridge crosses the River recommending a preferred option. where a higher road alignment was Barrow downstream of New Ross in the These were: found to be necessary. vicinity of Pink Rock (Figure 6), a notable local natural feature. The Haunched Box Girder Bridge It was envisaged that during Barrow valley at this point has two Arch – Single Span with “V” Piers construction there would likely be times distinct characteristics; the eastern side Arch – 3 Span when the navigation channel would be of the valley comprises a flood plain with obstructed to a greater or lesser degree Extrados Bridge – 3 Pylon grazing pasture divided into fields by by either temporary works (e.g. hedgerows whilst the western side is formwork, scaffolding etc.) or A bridge options report was prepared wooded and steeply sloping. Flowing construction plant (e.g. barges, which developed the preliminary design southward, the river is wide and gently craneage etc.). Whilst consideration of of these four options to a level sufficient curved, narrowing down to the constructability of each option took to determine comparative costs of each approximately 280m at the crossing such issues into account (with a view to option taking account of constructability, point. To the north of the bridge site the minimising disruption), it was generally programming & whole life issues. western bank of the river has been envisaged that periodic short-term realigned leaving an open area of “possessions” of the waterway would reclaimed land from which the new GEOMETRY need to be agreed between the crossing can be viewed. Horizontal and Vertical Highway contractor and the harbour authority Alignment during the construction phase. The proposed location for the bridge offers an excellent setting in which to The horizontal and vertical highway Air Clearance place a striking structure. The bridge alignments adopted for the four options “leaps” from the Pink Rock on the considered were based on those No power lines cross the site of the western side and crosses the river to determined for the scheme at the route proposed bridge structure. There are slope down across the flood plain selection stage. In the case of the also no airfields in the immediate vicinity towards the gently rising hills at vertical alignment, a 36m navigational of the structure, and the structures are Stokestown on the eastern side. The clearance option was adopted for the not significantly higher than the bridge deck would be of the order of 40 purposes of the bridge options study. surrounding topography. On this basis, metres above the river and would afford it was assumed that there were no potentially spectacular views of the The proposed structure is essentially restrictions on air clearance at the surrounding landscape and the River straight (except towards the abutments) bridge site. Barrow. and is orientated in an east-west direction. The road alignment is ARCHITECTURAL CONSIDERATIONS From ground level, the box girder option approximately orthogonal to the Design Philosophy provides a relatively unobtrusive direction of the River Barrow. The road solution, visible from within the cross-section adopted comprises two The architectural design strategy immediate landscape only. By contrast, 7.0m carriageways flanked by 0.5m adopted for the four bridge options was the additional height associated with the nearside and 1.0m offside hard strips, based upon a holistic approach to the arched and extradosed options results with a min. 0.6m raised kerb along each aesthetic and functional requirements in an impact over a much wider edge of the structure. As a minimum, a for the crossing. The proposed bridge geographical area. A number of Artist’s 0.6m wide high containment barrier is designs were considered to provide a sketches were prepared to assist with provided between the two carriageways, balance between the different functional evaluation of the alternative structures – but to accommodate the structural form and pragmatic engineering principally from a visual and aesthetic of the structures being considered, the requirements, whilst being sensitive to viewpoint. The sketches are illustrated extent of the division between the two their setting. in Figures 7 to 10. carriageways varies as required. No footways are provided across the structure.
Navigation Clearances
Data relating to river bed profiles were plotted to determine the width of the required navigation channel beneath the structure. Taking this profile and its intersection with the -3m Chart Datum Approx. Location of Crossing contours (i.e. where the depth of water at MHWS is 7.5m or greater - as specified by the Port of New Ross), resulted in a design channel width of 117m. The soffit lines of the respective bridge options were developed to provide a 36m clearance above high tide (Mean High Water Spring) over the width of the navigation channel as required by the Port of New Ross.
Based on the above criteria, the preliminary vertical alignment determined for the preferred route was Fig 6: View of River Barrow and Pink Rock looking north 7 MURPHY, SHINKWIN and MOYNIHAN Haunched Girder Bridge Option This option has a bold single arch Navigational arrangements would composed over the river linked by a require positive agreement with the high level viaduct forming the eastern appropriate authorities as this dictated approach. As for the three-arch option, both the vertical profile of the bridge and the arch is positioned along the the length of the main river span. centreline of the bridge, adding to the visual drama of crossing the valley The construction periods for the arch whilst still allowing unimpeded views off options were expected to be the bridge. The position of the arch also approximately 30% longer than either clearly defines the act of crossing the the box girder or extradosed options river itself. which would require approximately 30 months to construct. Three Tower Extrados Bridge Fig 7: Artist’s Sketch of Girder Bridge Option Having regard to all of the
considerations, the Extrados option was In contrast to the arched and selected on the basis that it had a small extradosed options, which make a visual increase in cost over the Box Girder statement on the surrounding bridge but it was considered to be landscape, the box girder option significantly better from an aesthetic focuses on functional simplicity, with a viewpoint and had a lower alignment modestly elegant design complimenting with a slightly shorter overall length. the boldness of its scale. The sides of the single box girder are inclined to reduce their visual mass which, together SITE INVESTIGATIONS with long edge cantilevers which put the A number of site investigations were structure in shade, further reduces the Fig 10: Artist’s Sketch of Extrados Bridge Option carried out to inform the design process apparent visual depth of the structure for the New Ross Bypass project. when viewed from a distance. This option is a bold contemporary design statement expressing intent for As part of the route selection process a Three Arch Bridge the future. The bridge has a tripartite preliminary site investigation was composition with a larger central carried out to broadly assess the ground element forming the visual focus of the conditions in various locations. This took scheme. To emphasis the slenderness the form of a geophysical investigation of this form of bridge the leading edge of (resistivity imaging) followed up by the deck is made as thin as possible by verification boreholes. A preliminary utilising a trapezoidal cross section with investigation of the riverbed was also haunches growing out of the soffit where undertaken at both major crossing additional structural depth is required for points (Pink Point and Marshmeadows) the longer spans. of the River Barrow to establish the nature of bedrock in the form of a COSTINGS geophysical investigation (sub bottom Fig 8: Artist’s Sketch of Three Arch Bridge Option profiling) Cost estimates were prepared for the This option comprises three arches various bridge options under To inform the preliminary design, two decreasing in size in line with the consideration. Measured approximate Ground Investigation contracts were elevation of the deck. The arch quantities were prepared for each option commissioned for the N25 New Ross members are positioned along the and priced on a common basis using Bypass by Mott MacDonald on behalf of centreline of the bridge with pairs of experience of projects of a similar Wexford County Council to facilitate the hangers arranged vertically at regular nature. preliminary design of the scheme. A intervals supporting the deck. The preliminary land based ground central positioning of the arches adds to Account was taken of the likely unique investigation was carried out which the visual drama of crossing the valley temporary works requirements, comprised cable percussion and rotary whilst still allowing unimpeded views off programme, construction techniques, drilled boreholes, trials pits, exposure the bridge by road users (subject to special plant and significant material logging, in-situ testing and laboratory open parapets being provided, with imports, and implications of undertaking testing. Piezometers were installed minimal wind shielding requirements). In the works at the particular location. along the proposed route to allow for elevation the line of the structure can be ground water monitoring. The field work likened to the path of a stone skimming RECOMMENDED BRIDGE was carried out between July and across the surface of the water. October 2006. An over water ground All four options were confirmed to be investigation was also carried out at the Single Arch Bridge appropriate for the crossing in terms of site of the proposed River Barrow functionality and architectural impact crossing, which comprised cable although it is recognised that the latter is percussion and rotary drilled boreholes, a subjective conclusion. All four bridge in-situ testing including static Cone options studied were expected to have Penetration Testing and laboratory only a modest environmental impact testing. The field work was carried out with visual impact possibly being the between September 2006 and January more contentious impact due to the 2007. subjective nature of the impact. Following scheme approval and The construction of all four options was confirmation of the CPO, further ground found to be feasible within the then investigation for the N25 New Ross known constraints of the site. Fig 9: Artist’s Sketch of Single Arch Bridge Option Bypass was commissioned by Mott 8 N25 NEW ROSS BYPASS MacDonald on behalf of Wexford A design navigation clearance of ADVANCED WORKS County Council. A land based ground 36metres above high tide (Mean Archaeology investigation was carried out which High Water Spring Tide) shall be comprised cable percussion and rotary provided over the width of the The archaeology contract for the N25 drilled boreholes, trials pits, in-situ navigation channel (defined by the New Ross Bypass, commenced in testing including Standard Penetration Port of New Ross as the width of November 2009. The bulk of field Tests, Dynamic Cone Penetration Tests, water with an available draught of works, including test trenching, Soakaway testing and laboratory 7.5m or more at Mean High Water identification of sites and resolution of testing. Piezometers which had been Spring). these sites was completed in December damaged between 2006 and 2009 were Architectural lighting shall be 2013. re-installed. The majority of field work incorporated to delineate the bridge was carried out between October and at night and shall be designed so as There were outstanding works to be December 2009. Due to poor weather not to conflict with navigational completed and these extended to the conditions, the contractor demobilised lighting. testing of the lands to the west of the from site in December 2009 and River Barrow crossing (approx. 1200m) remobilised to site in August 2010 for a In December 2008, An Bord Pleanála and the resolution of 2 further sites period of two weeks to complete the issued an order granting approval to the identified in the original test trenching. field work. Scheme and confirming the CPO Order. which were resolved in early 2014. A number of areas were identified which CPO AND EIS ORAL HEARING SECOND PPP ROADS PROGRAMME would not be resolved during that Archaeology contract and these areas Wexford County Council applied to An Following the successful award of the were included in the contract documents Bord Pleanála for approval of the contracts in the first PPP roads to be resolved by the Contractor. Environmental Impact Assessment programme, the National Roads (EIS) and confirmation of the Authority (NRA, now Transport 220kV Service Diversion Compulsory Purchase Order (CPO) in Infrastructure Ireland (TII)) announced November 2007. An Oral Hearing into in February 2009 that it was proceeding The Great Island – Kellis 220kV ESB the CPO and the EIS was held by An with a Second PPP roads programme line traverses the N25 New Ross Bord Pleanála in April 2008. with the objective of delivering new road Bypass route at the N30 Tie-in. There
construction with a capital value of €1 was inadequate clearance between the At that time of the oral hearing it was billion through private sector funding existing overhead line and the proposed envisaged that the N25 New Ross under a PPP mechanism. In June 2009 vertical alignment of the N30 Tie-in. A Bypass scheme would be procured by the NRA released an updated Second new 220kV tower was agreed with ESBi means of Public Private Partnership. As PPP roads programme. The N25 New and was erected adjacent to the N30 a result, some latitude would need to be Ross Bypass was included and at the Tie-in. given to the bidding consortia in relation time it was envisaged that the N25 New to detail design, however, it was also Ross Bypass would be joined with the Environmental Survey desirable to enshrine the essentials of N11 Gorey to Enniscorthy. the bridge within the Scheme Orders to In November 2009 the NRA appointed To support the delivery of the scheme, ensure that the chosen structure would the ElevenTwentyFive Consortium an advanced environmental survey was be delivered. For the purposes of the (1125) comprising of consultants Mott commissioned. A survey was Scheme Orders, the essential features MacDonald Ireland Ltd and Ryan conducted within and along the scheme of the recommended scheme were Hanley WSP to progress the N11/N25 for Badgers, Bats, Otters and Invasive described as follows at the Oral Hearing PPP Scheme through to construction in Plant Species. The findings of the and these were enshrined in the accordance with processes laid out in advance environmental survey served to Schedule of Commitments: the Project Management Guidelines update the conclusions of the ecological
2010. surveys undertaken as part of the EIS The main tower will be of the order for the N25 New Ross Bypass. of 25 metres in height above deck In Q1 2013, the NRA made the decision level. that the M11 Gorey to Enniscorthy A report was produced which provided There shall be a single line of towers Scheme and the N25 New Ross Bypass results of the advanced environmental (and cables) in the centre of the would be progressed as separate PPP surveys, recommendations of necessary structure. Projects. Subsequently, Mott mitigation measures and any potential The two adjacent towers shall be of MacDonald Ireland were appointed to requirement for further survey work. the order of 15 metres in height progress the N25 New Ross Bypass above deck level Scheme from NRA Project Management PPP TENDER PROCESS The two main spans will be of the Guidelines (PMG) Phase 5 Advance order of 230 metres. The tender process for the PPP scheme Works & Construction Documents The approach spans on the western originally commenced with the Preparation, Tender & Award, through side shall be generally of the order publication of a notice in the Official Phase 6 Construction & Implementation of 45m, 60m and 86m (starting from Journal of the European Union (OJEU) to Phase 7 Handover, Review & the west). on March 22nd, 2010 but was Closeout. The approach spans on the eastern suspended later in 2010. In July 2012 The scope of work included in the side shall be generally of the order the Government announced an technical advisory services include: of 45m, 60m, 60m and 86m (starting Infrastructure Stimulus Package to 1. Stage (ii) Design from the east). provide investment for a range of 2. Stage (iii) Tender Action, The cables shall be arranged in important public infrastructure projects Evaluation, Award parallel to one another. including the N25 PPP Scheme. The 3. Stage (iv) Construction (Phase 6 The towers shall flare towards the Tender process for the N25 New Ross PMG 2010) top with curves oriented to Bypass PPP Scheme then re- 4. Stage (v) Handover (Phase 7 PMG compliment the inclination of the commenced with the publication of a 2010) support cables. notice in the OJEU on March 22nd
2013. 9 MURPHY, SHINKWIN and MOYNIHAN Works. Responsibility for the design, Compliance with the Construction Four consortia were prequalified for the construction, supervision and Requirements tender. They were: commissioning of the works lies with the Compliance with other provision of New Ross Joint Venture (NRJV) the Agreement. BAM Iridium comprising a joint venture between BAM Banba Consortium Civil and Dragados SA. Design and The PPP Contract provides for review Sli Nua construction of the works is required to periods of 20, 10 and 3 days, depending on the type and status of certificate Direct Route be undertaken in accordance with the received. Within the relevant time the Construction Requirements (Sch 4), the ASR will return a signed certificate The Invitation to Negotiate including Conceptual Design (Sch 28) and the advising a status of Acknowledged, tender documents was issued in Certification Procedure (Sch 5). The Acknowledged with Comments or November 2013 and following a number Certification Procedure provides for the Rejected, together with reasons for of tender consultation meetings tenders submission of Quality Documentation, rejection or acknowledgement with were returned in September 2014. Design (Highway, Structures, comments. The ASR may also request Earthworks, etc), Departures from further information considered Following evaluation of the tenders, Standard, Archaeology, Ecology, necessary for the purpose of review for both technical and financial, a contract Alternative Conceptual Designs, Third compliance of such submissions with was awarded to BAM Iridium and the Party Consultation, Road Safety Audits the Agreement. contract was signed on 26th January and Temporary Works Design under an appropriate certificate by the PPPCo to 2016. In advance of the initiation of the CONSTRUCTION - DESIGN REVIEW the Authority. The review of the documentation is a function delegated submission of documentation under the PROCESS by the Authority’s Representative (AR) certification procedure, MMI, NRJV and their Designer agreed a procedure for The PPP Agreement between the to Mott MacDonald Ireland (MMI) and the Authority’s Site Representative the submission and tracking of Authority (National Roads Authority) and documentation. The procedure included the PPPCo (BAM Iridium) comprises the (ASR). the transmission of documents NRA PPP Contract and NRA PPP Documentation received from the electronically by the use of a secure Contract Schedules. The Contract PPPCo under certificate, in accordance Extranet. Further to the uploading of Schedules include Tender Proposals/ with the provisions of the Certification documentation, electronic notification is Conceptual Design (Sch 28), Quality Process (Sch 5) is examined for automatically circulated to relevant and Environmental Management (Sch compliance with the Agreement parties with original hard copies of 10), Certification Procedure (Sch 5), including examination for: certificates being provided directly to the Land Issues Roads and Orders (Sch 2), ASR. Third Party, Construction and O&M Consistency with the Conceptual Requirements (Sch 3, 4 & 7). Design included in Schedule 28 A scheme of the magnitude of the New Compliance with the Certification Ross Bypass necessitates the Obligations of the PPPCo include the Procedure submission of a large number of design, construction, operation, Consistency with the EIS and certificates. To date (April 2018), the maintenance and financing of the compliance with the Orders certification has included approx. 2100
Fig 11: New Ross Bypass 10 N25 NEW ROSS BYPASS Design submissions and 100 Method 1.2 km of Std Single Carriageway carrying the disused but not Statements. In the region of 4400 forming a tie in between the Mainline abandoned New Ross to Waterford design drawings have accompanied and the existing N30. railway line over the N25 Mainline. design received to date. Three At Grade Junctions, at The bridge is a post tensioned Glenmore, Ballymacar Bridge and reinforced concrete structure with a Corcoran’s Cross forming main span of 38m. connections between the Mainline Structure BC River Barrow Bridge and the existing N25 and N30. An 887m long extrados bridge crossing One Semi-Compact Grade the River Barrow with a navigation Separated Junction at Landscape clearance of 36m at MHWS. This connecting the mainline to the R733 structure comprises 9 spans with 2 no. Arthurstown / Fethard Road. 230m long main spans. Three Total of 37km of Mainline, National, reinforced concrete pylons located in Regional, Local and Access Roads. the central median support the cable Fig 12: R733 Junction under construction The construction of in excess of 46 arrangement. The pylon at the central principal Structures including: river pier is 27m above deck level (60m For the purposes of ensuring a 3 road overbridges, 8 road above foundation level) with the coordinated and timely response to underbridges, 1 railway overbridge, adjacent pylons in the order of 16.2m documentation received under the and 16 accommodation above deck level. certification process, a comprehensive underpasses database driven document control The construction of an approx. 900m system, including an Office 365 long Extrados bridge with 2 main Sharepoint Workflow system, was spans of 230m carrying the Mainline created and is maintained by dedicated across the River Barrow. MMI Document Controllers. This Diversion of various Services, provides realtime listings of necessary Landscaping, and Accommodation actions, document status and register Works. listings of all certificates, design drawings and other documentation Fig 14: Cable Testing at CTL, USA received. An Office 365 SharePoint site is used to store project documents and It is a continuous concrete box girder generates workflow tasks to alert each deck over its entire length with the depth reviewer of submissions to be reviewed. of deck varying between 3.5m and 8.5m The design/documentation reviewed by with fixity at the approx. midpoint in the MMI includes the following: bridge at Pier 4. Approach spans are constructed using formwork supported Quality Documentation (Design, from ground surface with the main Construction, O&M) including spans at Pylons 3, 4 & 5 constructed Method Statements using Cantilever, and Balanced Alternative Conceptual Designs Cantilever methods. Review of Departure and Variation Fig 13: Barrow Bridge under construction
applications CONSTRUCTION – ELEMENTS OF Discrete feature lighting will illuminate Design Review including Site SCHEME DESIGN the pylons and stay cable arrays with Clearance, Fencing, Ecology, spill controlled uplighting. A continuous Road Layout, Structures, Earthworks row of LED luminaires will illuminate the Earthworks, Drainage, Utilities, By careful management, areas of cut bridge deck edge. On completion the Lighting, Kerbs, Pavement, Signs generated sufficient material for the River Barrow Bridge will be the longest & Road Markings, Safety Fencing, necessary formation of embankments, bridge in Ireland with a length of 887m Landscaping and Environmental generation of road construction product, including two main spans of 230m. Works, Accommodation Works environmental berms and landscaping Temporary Works and Third Party areas. Cut slopes in competent rock certification were optimised by detailed design. Traffic Management and Road Blasting was utilised in cuts in Safety Audits Glenmore, Stokestown and Camlin. Design in softground areas, located CONSTRUCTION - principally at Glenmore, comprised SCHEME REQUIREMENTS IN BRIEF replacement with suitable material.
The Construction Requirements set Structures down particular design and construction In addition to the numerous requirements for the scheme. In brief underbridges, overbridges, underpass the requirements included for the culverts and the 900m Extrados following (Refer also to Fig 11): crossing of the River Barrow, New Ross Bypass boasts other structures of note 4.0 km of Type 1 Dual Carriageway including: (Mainline) between Glenmore Co. Structure B01 Ballyverneen Kilkenny and R733 Junction in Underbridge: This overbridge carries Landscape in Co. Wexford. the N25 Mainline over the local road 9.6 km of Type 2 Dual Carriageway (LS-7513 and the Graiguenakill (mainline) between the R733 Stream. Junction and Corcoran’ Cross Structure B02 Ballyverneen Railway Junction. Bridge: an 80m long 3 span bridge Fig 15: Pier 4 Balanced Cantilever Form Traveller 11 MURPHY, SHINKWIN and MOYNIHAN Jan 2006 Bridge Options Report T. Gunning Former Dir. Of Services Oct 2007 Prelim Design Report & EIS O. Mannion (RIP) Former Sen. Engineer Nov 2007 Application to An Bord J. Gannon Former Proj. Liaison Officer Pleanála (ABP) Apr 2008 Oral Hearing Tramore House RDO: Dec 2008 Scheme Approval ABP G. Jones Senior Engineer Early 2009 New Ross Bypass C. Daly Proj Manager combined with M11 R. Butler Former Senior Engineer Enniscorthy as combined A. Curran Assistant Engineer PPP Scheme Mott MacDonald Ireland Mid 2013 New Ross Bypass to be J. T. Murphy Project Director progressed separately J. Shinkwin Project Manager Nov 2013 PPP Tender Issue B. Williams Structures Sep 2014 PPP Tender Return J. Hawe Highways Jan 2016 PPP Contract Signing J. O’Riordan Highways M. Cotter Highways ACKNOWLEDGEMENTS M. Murphy Road Safety The authors wish to thank Transport A. Costello Drainage Infrastructure Ireland, Wexford County N. Samachetty Drainage Council and Kilkenny County Council for D. Wrynn Highways their permission to publish this paper J. Fisher Director – Bridges Fig 16: View from Pier 3 Barrow Bridge They wish to record their thanks to the P. Churton Barrow Bridge
staff of all three organisations as well as E. Morrissey Structures Project Statistics the staff of Tramore House Regional C. Arnold Geotechnics 13.6 km Dual Carriageway Design office for their invaluable B. Moynihan Geotechnics & Highways 1.2 km Single Carriageway contributions throughout the project. P. Kelly Environment R. Hallissey Environment 23 km Other Roads PROJECT TEAM R. Mansfield Ecology & Landscape 1 Grade Separated Junction L. Burke Health & Safety 46 Structures including: Transport Infrastructure Ireland: J. D. Shinkwin Former Project Director - 8 underbridges for roads K. Downes Regional Manager - 3 overbridges for roads M. Bowe Senior Engineering Inspector Mott MacDonald Ireland –Site Staff - 1 overbridge for railways & Authority’s Representative P. O’Loughlin Authority’s Site Rep - 16 underpasses M. Nolan Chief Executive K.Boland Sen Resident Engineer 887m Extrados River Barrow Bridge G. Fitzpatrick Head of Roads Capital C. Fox Sen Resident Engineer A. O’Dunlaing Sen Resident Engineer River Barrow Bridge Statistics J. Iliff Network Manager (Structures) F. Cahill Senior Engineer (Structures) M. Wade Barrow Bridge Specialist Extrados Bridge carrying dual J. Eogan Project Archaeologist R. Miles Sen Resident Engineer carriageway over the River Barrow M. Kennedy Senior Proj Manager (PPP) M. Scully Sen Resident Engineer crossing between Kilkenny and J. Fitzsimons Sen. Proj. Manager M. Boyce H&S, Quality Manager Wexford. W. Douglas Sen Engineering Inspector D. Byrne H&S, Quality Manager H. Hughes Dir. Prof. Services P. Doheny Resident Engineer Overall width: 19.9m – 22.96m D. McIlraith Former Sen Proj Manager T. McDermott Resident Engineer Overall length: 887m D. Clear (RIP) Former Inspector N. Belamaric Resident Engineer Main spans length: 2 no 230m M. Grennan Resident Engineer Wexford County Council: (Longest span in 26 counties. Foyle O. Brennan Resident Engineer T. Enright Chief Executive Bridge in Derry NI has a main span J. Creedon Systems & Roadworks E. Hore Director of Services of 234m) K. Ennis Inspector N. O’Driscoll Senior Engineer Side span lengths: 36, 45, 95, (230, L. Burton Inspector S. Dobbs Project Liaison Officer L. Boyle Inspector 230) 95, 70, 50, 36m A. Dunne Sen Exec Engineer Clearance over MHWS: 36m R. Kearney Inspector E. Warren Clerical Officer S. Hussey Certification Co-ordinator Overall Central Pylon height: 60m S. Dooley Former County Manager L. Webster Sen Administrator (above foundation) E. Breen Former County Manager H. Shalloe Administrator Certification Height of central pylon above road P. Callery Former County Engineer M. Aherne Administrator level: 27m A. Doyle Former Dir. of Services A. Kinsella Administrator Height of adjacent pylons above N. McGuigan Former Dir. of Services D. O’Mahony Administrator road level: 16.2m E. Taaffe Director of Services Cables (Parallel):P3 & P5: 8 cables Former A/Senior Engineer BAM Iridium each; P4: 18 cables J. Power Former Senior Engineer R. Urien Laso PPPCo Rep A. Madders Former Senior Engineer Total length of cable ~ 4400m L. Mackey PPPCo G. Walsh Former New Ross Town Eng Diameter of cables (Outer sheath): D. Curtin Former Project Liaison Officer NRJV - BAM/Dragados 315mm comprising 113 to 127 M.McArdle Former Clerical Officer T. Lucey Project Director strands (Approx 500km of strand) A. Cunningham Contractor’s Rep PROJECT SUMMARY Kilkenny County Council: D.Espino Construction Manager C. Byrne Chief Executive K. Tully Engineering Manager Mar 1999 Appointment of Mott T. Butler Director of Services D. Roche Barrow Bridge Manager MacDonald S. Walton Senior Engineer Mar 2000 First Public Consultation I. Gardiner Sen. Exec Engineer NRJV Designers Feb 2001 Constraints Study F. Stafford Sen. Exec Engineer ARUP (Main Designer) Nov 2001 Second Public Consultation D. O’Sullivan Former County Engineer Carlos Fernandez Casado (Barrow Bridge) Oct 2002 Route Selection Report J. Mulholland Former Dir. Of Services Eptisa (Cat 3 & Independent Checker) 12