*DEPARTMENT OF MAI NEW SOUTH WALES Issued by and with the authority of the Commissioner for Mah Roads

100000001 News of the Month. Metropolitan Division. and Batliurst werc tar-surfaced by way of experiment. Very scverr rain

f3ridzc ovrr ihc 1 ur~nRrvcr nrar Sofala. on thc Suf:tI+blud~c~road (No. L 161 the Strathfield-I:iitieltI I~~~~intIaryis I)eing increasctl in !i;rougllout. This lcllgtll ui I-~JXI \\;is nrigiclally COW width to 24 feet between kerlis. The opportunity is !-tructerl in waterbound nlacadam. surface treated, with being taken to cotistruct a iootwap 011 one side of the a pavement I j-16 fcct wide and with excessive cross- bridge. The cost of the fciotway is being met by fall. It has been widened by building strips of pcne- Strathfield and Enfield Municilial Councils. tration niacadaiii on either side of the existing pave- In 1930-31, short sections of the gravelled surface ment. the strips being placccl as iar as possible to of the Great Western Highway between Mt. Victoria increase the radius of the curves ancl to permit of *r1634 122 MAIN ROADS. Vol. IV, No. 9. ~~ _~____ sul)cr-elcvatioti. ‘l‘lic work is now bcitig coinplctetl I‘lic 1)epartmeiit has just conipleteil tlie rcpaintitlg hy the atlrlilioii of :I sheet of drag-slireatl coirl-inixed of thc hrirlge over thc i Iuntcr Itivcr :it SiiigIet(in, 011 inacad;uii. whicli will improve the riding qualities. tlie New I

New mnnforcecl concrete bridne of two 35-h. spns rccenlly erected by the DPpartmcnt over Coomliinr: Creck. Mid- \Vestern Highway, Lyndhurst Shire. For many years the southern approach to thc bridge the triple-cell 9 ft. x S ft. culvert recently constructed over Stewart’s or Jolni’s River. on the Pacific High- at Frogs’ Hollow, 14 miles from Tn\wdl. will mark way in Msnning Shire. has Iwcn tlie cause of traftic the elimination of the worst of the open crossings stoppnges in time of flood. ’lhis has been due as niuch within the Shire. to the mieveti grade of the roatl as to the actual level of the flootl. as dips in the road blocked traffic when Tlic bitumen penetration work 011 tlie Kew England (ither higher portions could he safely negotiated. Higliwa); in Guyra Slrirt.. referred to in “News of tlic ,.1 herefore, arrangements were made this year for the h4onth” in the 1~)ecember.1932. issue of Mair1 liontis. C‘oiincil to raise the apl)roacli slightly, to a cinifnrni lias Ixen coml)letetl. with the crception of the bitumen level, illcrease the cul\Terts, ali(l seal the l)”vementwitll seal coat. as far as +hc ~outllernshire I)ou11(lat-yat 7 1x1. 1)itumen to prevent scour. i\s high floods wtrultl still IS ch. from Guyra. inundate the road for 15 chains. lntters of 3 to I Work is now in progress in connection with the were left 011 tlie lower side of the tills. Thc work reconstruction nf a sinfile 35 ft. span reinfnrcctl con- Iiatl just been completed. hit had tint had time to coli- crete 1)ritlpc over Spring Creek, Iletween (;raveseiitl solidate, when a high flood in the first week of April atid Liinigoy. on the Gwydir Highway in Yallaroi Shire. washed out part oC tlie I)ank and tlamagetl thc pave- The construction nf this bridge is a ncccssary part nient. l’hc brealis will be repairecl, and it is hoped of the work involved in the completion of ail all- that the work will Iiave had time to consolitlate and weather road from \\‘ariaIda to Ihiguy. as referred to grass will hve esta1)lishetl itself on the batters sufii- in “Kews of the Llonth” in tlie Fc.bruar)-, 1933,issue of ciently to I-csist scour before another high flood occurs. Mnin Roads. May, 1933. MAIN ROADS. I23

North-Western Division. 'I'hc illustration oil this page shows one of a iiuiiiLer of very old Iiewii stone culverts on the Scw England Highway in the Shire of Nundle. The culvert shomti is of 4 ft. 6 in. span. and 3 feet high. with stone slab decking IL' inches thick. l'liis onc is in good ortlcr, apart froin the stones dislodged from tlie heatl\valls. :iltliough others nearby h:ive tlevelopetl cracks in the decking. Culverts of larger spar have been built with stone corbels in order to limit the clear span of the deck slali to 4 ft. 0 in. Coiitr;ictors liryaiit ;uid Buchanan have cotnpletctl X miles of tar-surfacing on \\':irlands Range deviation, on tlie Nciv l

Central Western Division. Roller used for tar-surfacing Warland's Range deviation. Good progess is being niatle by Contractors N. H. New England Highway. showing set of brooms used for distributing the aggregate evenly. Jones antl Co. on the construction of thirteen reiii- forcvtl concrete box culverts on the Mid-Western 1 lighway in tlie Shire of Lyndhurst. Thc culverts range on the ArtIiurville-(;eurie devclopniental road (No. in size from single-cell -1- ft. x I ft. 6 in. to two- 1007) in the Shire of ('ohbora. The repairs consistcd cell 8 ft, x 4 ft. Some will replace worn-out timber of renewals of one cap sill. one corl)el. four girders. one culvcrts. and the remainder will eliminate V gutters. 60-foot pilc and 7,000 super feet of carriage-way deck- ing, together with filling in a lat-gc scour and general Tn connection with the inaintennnce by the Ilepart- tightening-up. nient of the section of the Nortll-Western highway in the Shires of Tabragar antl Tinil)rebongie and the Municipality of Narromine the following contracts for Southern Division. the supply and sprcatlillg of gravel have ' heeii corn- The construction of concrete pipe antl precast box pleted :-lhl)bo-Ge~rie ( l'alliragar). 2.640 cubic yards, culverts to eliiiiiiatc causeways on the Cooma-Mt. Cotitractor _I. E. Pucket-irlge ; Dubbo-Narrotnine ( Tin- liosciusko road (No. 2%) lxtwecii the Hotel brebonxie), 1.314 cubic yards, Contractor J. Bryant; liosciusko atid tlic silturnit of the mountain has been Narromine-Trangie ( Timbre1)oiigie aiid Narrolninc) , completed as far as 2-1 in. This has consitlerably 1,616 cubic yards, Contractor J. (i. Niller. iniprovcd the running surface aiitl will greatly facilitate The divisional bridge rnaintenance gang has repaired the maintcnaiirc of this scction. which is suhject to the bridge over the Macquarie Kivcr at Scabbing Flat, severe weather conditions while snow is melting in the spring. Contractor \\-. D. McUonald has coiiiiiienced tlie constructioii of concrete box culverts at 3 m. 3.310 ft. and 3 m. 4.240 it. on the Coonia-:4tlaminaby section of the Monaro Highway. The contract also includes the construction of box culverts at 7 m. 89j ft. and 8 111. 2,720 ft. A11 of these crussiiigs at present hold up traffic iii wet weather. Governor's I Till ticviation. on the Humc Highway one mile north of (;oull)urn. has been completcd antl opened to trafic. 'Tlic iniproveinent of the grade (from IO per cent. to 6 per cent.) is of particular Ilene- fit to horse-drawii traffic. The new road is I m. 650 ft. long. Funds for the work mere provided by the Unemployment Relief Council. The divisional I)ritlge gang lias completed overhaul- and painting the 1)ritlges over Coolumbooka \'cry old stone culvert on the hew England HtEhway in ing River. Nundle Shire. Cranlties Plains. on thc Bombala-Cathcart section of 124 MAIN ROADS. Vol. IV, No. 9.

__ ~~

the ~oiiil)ala-l'xmbularoad (No. 274) ant1 over the Contractors 'l'Iiom1)soii :cntl Mc I'herson have coni- 1'miil)ala River ;it Honibala, on the Ninii~iital~el-I!oiii- pletetl the work of raising ant1 gravelling 4.5" feet of bala trunk rod (No. 53). Thc gang is at present the Monaro Highway in Kyeaniha Shire iiear Forest repairing tlic Iwitljie over the Bombala River at Hill turnoff. The work will prove of great I)cncfit C'~uininghani'sPoint. on the latter road. to users of the road (luring the winter months, as this sectioti was previously subject to inlintlation after South-Western Division. heavy rains. Tumut Shire Council has in hand at the present time Repairs are being carried nut to the hridge over the the building of four low-level timber bridges over Murruml)itlgee Kivcr at Darlington Point, on tlre Kiley's Creek. on the Tumut-Yass road (No. $3) 1)arlinjiton I'oint-Griftith road (No. 321 ) in Murruni- north of Tuiiiut. The existing open crossings have I)itlKee Shire. hy one of the divisional bridge gangs. always been a source of annoyance. and, at times, The work consists of the renewal of certain piles. clanger to motor traffic, atid have often lield up vehicles girders, corbels. and decking. Upon completion of the for several hours. 'The road, over this section, passes repairs the bridge will be painted. through hilly country atid is narrow atid tortuous, with ICstetisive inilirovenients have been effected hy the many steep grades. It will be many years before any Waradgery Shire Council to the Moama-Booligal relocation will be possilde. The liritlges are IO fect trunk road (No. 60) by the reforming and loaniing wide between kerljs. The short approaches will be of sections which have in the past cut up badly in wet of rock, with a hatitl-packed retaining wall on each weather. The work carried out should be of great side of the enibanknient, thus ensuring that no erosion advantage to traftic (luring the coming winter months. will occur. Expenditure from 1st July, 1932, to 31st March, 1933.

Expenditure for lotai Espenditure Munth of from cst July, 1932, Hnrch, 1933. to gist March, 1933.

COUNTYOB C.UMBERI.ANDMAIN ROADS FUND- Chnstruction of Roads and Bridges ...... Cost of Land llesiimptions ...... Maintenance of Knadq and Rridges ...... Rcpayincnt of Loans ...... Survey, Design. Supervision and .%dministration .._ .,. Miscellancous ......

Tutals ...... 339.63' 0 8

COUNTRY hTAIS ROADSFUKD- Constroction of Hoads and Rriiigrs including Ji~snniptions ... 1<>6,875 ,j 4 Maintonancc of Roads and Bridges ...... so3.159 '7 T Repayment of Loans ...... 37.304 6 3 Survey, Iksign. Supervision and Administration ...... 61,812 8 7 Miscellaneous ...... 38.637 13 10

Totals ...... 837.78911 j FEDERALAID ROADSFUNU- Construction of Roads and I3ridgcs inclndinp; liesunipiions ... 54,318 I<) 8 Miscellaneous ...... I49 '7 7 Totals ...... 54.468 xi 3 DEVELOFMENTALROADS FUNU--- Construction of Roads and Bridgcs ...... 8,21838 6,309 IZ IO 14.52j 16 (I Survey, I)rsign, Supervision and Administration ...... 903 9 2 ...... so3 9 n lla11cous ...... 241 I<, I 209 12 IO 45' 11 11 Totals ......

SUMMARY ALL FUNDS- Cnnstroction of I

SYDNEYJIARBOUR BRIDGEACCOUNT- Administration ...... Cost of Maintrnance and Toll Collection ......

Totals ~...... Credit. May, 1933. MAIN ROADS. 125 Hot Mixing Plant at Rosehill Depot. BY L. W. HAWLEY,B.E., A.M,I.E.AusT., Engineer.

replaciiig an existing hot-mix macadam mixer, hot hinder for the Department’s general maintcnance BYthe Department has rcccntly increased the operations in the vicinity. capacity of its plant installed at Rosehill Dcpoi Plant Lay-out.-The reorganised plant is made up of for the supply of hot-mixed materials for use on those two hot-mix units. Che is a Niven machinc. pur- main roads maintained directly hy the Illetropolitan chased from Cobbora Shire Council, and the other is Division maintenance branch. one of the Uepartment’s Armstrong-HollalIrl mixers. ’The Depot is situated near the centre of the network These have been erected sidc hy side upon permanent of niain roads converging upon Parramatta, in an concrete foundations adjacent to the existing aggregate excellent stratcgic position for hantlling materials by storage bins. Each has been adapted and improved motor lorry in any direction within the limits of to suit the work which will be rcqulrel of the new economical working. installation.

.”.

General view of plant. Arrnatrong-Holland machine on left, Uiven machine on right.

Originally, the principal duty of the Kosehill mixing For the present. the output of sheet asphalt and plant was to supply mixtures of the coarse-graded similar fine-graded niixtures necessitating very accurate macadam type for patching black-top roads. hut conse- proportioning by weight will not be beyond the capac- quent upon the success of the drag process for recon- ity of one Inachine. The Niven plant being already ditioning old surface-treated and tar or bituniinous equipped with screens and separate hot aggregate inacadam paveincnts. a demand arose for an increased storage bins. it was eqnipped with weighing devices output of mixture for this work.* Also limitctl quan- for producing accurately-gratletl mixtures. tities of sheet asphalt are required. The pavements Each plant is supplicd with aggregates from the of this type built iu the early years of the Main Roads bins by individual volunie-l,roportiotlinp devices leatl- Hoard are all subject to maintenance by the rcsliective ing to chain-bucket elevators feeding the driers. .% contractors for several years after completion. but. with binder heating and circulating system, of which the the expiry of these periods. will pass to the care of the principal items. the kettles. are standard portable 500 maintenance branch directly. and 800 gallon units. supplies either or both mixers, as In addition. the aggregate storage bins associated well as the power spraycr. The paddle (or pug-mill) with the mixing plant are relied upon for supplies of mixers discharge into loading t1opI)er-s each capable of brolten stone. and the heating equipment will provide storing up to (J tons of material., From the hoppers, thc material passes to motor lorrtes, and thence to the * For description of the drag process for reconditioning worn bitumhou pavements, see Main Rod3 June, 1gj2, p. 148 and January. ,933, p. 69. road. I26 MAIN ROADS. Vol. IV, No. 9. -- ~ ..

Aggregate Storage Bins.-The aggregate (liroken stone to identical scales. to oljtain a chart from which can atid sxticl ) is discharged directly from wilway hopper be read off the size of openings necessary iti the feed trucks into the receiving boot of a 1)idet-brlt elevator. boxes to give different pro1)ortioiis. From the feeders which raises the material to a set of covered bins. It the aggregates gravitate to tlie Imots of the elevators is distributed by a horizontal Mt conveyor :ind tlc- which discharge into tlic driers of the mixing m:icIiines. flcctitig chutes. The elevator is tlrivcii by a io 11.1). Niven Mixing Unit.-Tlie drier consists of tLruiii sIil>-ring iiitluctioii tiiotor atid the Iiorizuntal conveyor a revolviiig at r.p.iii. ?fhe aggregate is fed in at Iklt by a 5 1i.p quirrcl-c;ige ititluctioti inntor. For- 922 merly tlierc were four bins. Iiaviiig a total capacity of one end antl. after drying atitl lieating. is discharged at the other ciitl into ;i chain-lmcliet elcvatcr. The hot ,joo totis. These have IIOIY I)een tlividctl into riglit cnmpartiiiciits, four of which have I~cei~allotted to gases from the furnace enter at the discharge end through pirts in the tlrum and are tlran.n tliroiigh tlie c.:icIi iii;ichiiie. In each groul) of four cniiil)artiiienth tlricr iii the opposite direction to the materials by a there are two with a cali;icity of So ton> each aittl two of 40 tons. I. Ir%-incli tliameter mill-type f:in runtiing at yor.p.111.. iiiiil are tliscliargetl at ljrescnt to tlic atniosplicre. It II'Iieii tlie plant is tilierating to its full calracity, over is Iiroposetl to 1:ig the cuver of tlie drier wiih iiidatiiig 2:~)tons of aggregate \vi11 Iw requirctl per day. The material in order to retlucc hcat wastagc hy radiation, c-qiacity of the Ilins lieiiig sutlicicnt for only two thys' which is at Ibresent con.sirleralilc. 'l'his wiit 1i:is been work, stock-piles in tlie Ikpot yard will he niatle to fitted temporarily on trial with an rlectrically-tli-iveii provide against irregular tlc1ivcrit.s of :tggregate. This rotary crude oil litiriier of 12 gallons per liriur calncity. tn;iterial will he liable to I)ecome wet, which restricts Slroultl the trial ~irovesuccessful. the burner will bc thc output ol a plant. I~ccau~eit malies drying antl retained ancl pcrniaiiently itistalletl. hc;iting more tlifiicult. particularly in the case of tlic

tincar aggregates. Therefore. the larger coiiipartiiieats I1 \vi11 be used for the storage of tlie finer aggregates to Iicep as much ni these materials as pnssilile uiider rover. Incidentally. this arrangement of tlie partitions 4oTOEIS 40TONS fits in \vel1 structurally with the coiistructinn of the WTONS BOTONS Iiiii? and permits ready drawing-off of iiiaterial for €/a* 1m-1iose>,other than the plant. 00TONS BOTONS From tlie 1)ins the aggregate gravitates tlown chutes ,! SAND S*NO .01rnB to tlic ~~roportioningfretlers. rh ..¶To"* $ U U m ,M m.%m Proportioning Feeders.-Two reciprocating 1)ropor- 3 2% hnai tioiiiitg feeders (onc for each miser) arc plac-rtl uiider Q tlie bins. These feeders consist essentially of four Imxes placed in line almve a rrciprocatiiig plate driveii liy tulnilar steel connecting rods attached to discs on a chain-drivcn counter-shaft mountctl above aiid parallcl

to the lower sprocket shaft of tlie respective elcv:itors KICAUM to the driers. The proportions can lje c1i:ingetl by adjusting tlie openings of the gates of thc feed Imxes. _.I lie rate of feed can Ire wried by altering the strolx of the plate. The plate. rcciljrncates at the rate of sistccii strokes per minute. aiitl tlic length of stroke can l)c varied in Iialf inches 111) to 12 inches. The General arrangement of plant. shown diagrammatically. capacity ol the feeder. using the Rra'nch's standard reconditioning mixture. is I; totis of aggregate per The heated aggregate is tlisclrargctl into ;L aj-inch Iiour. dianieter screen I-cvolviiig ;it 20 r.p.iii. :\s origin;iIIy I\S the design \vas iin\-el. tltc first fectler inatle \v;I< iii:ide. the scrceii coiisisted of 'three sections. the per- c~instructetlin tiiiilicr. Irut it I)ro\-etl quite successful. forations ancl lengths I)eing inch dinmetel-. 20 inches ; :ind the secotitl (me. with ininor iiii~m~vciiieiits.was p&inch tlianieter. 16% itrclies ; and 1 >$iiicll tliameter. fa1)ricatcd in steel. The origiital nootlen feeder will 16% inches. For fine-graded mixtures. :I scrceii with lie relruilt later in steel. perforations of a1)proximately io mesh is tlesiralile. Init From actd weigliiiigs it has I)C~II ;c?c.ertaine(l that. the Ikpartment having avai1al)le a screell plate with for gate ol)enings of T itich and over in the case of .;/pinch apertures [ which lie Ixtwcen a No. 4 mesh s:iiid ;ind ;-i6tIi inch gauge stone. antl II[ 2 inchcs ant1 aiitl a No. S mesh screen). this \vas t~setl to mike :I over in thr case of 3i-iiicIi gauge stone. straight-litic sliroutl 22 iiiclies loiig mtl 30 inches iii tliametcr ;~rouiitl graphs are ol>taiiietl by plotting sizes of opening ac$ii?t tlie $&inch section. 0rtlin:Irily the masiiiiu~iisize of ~rrlunies of material pasred per unit of time. By stone used in plant-mixctl \York for ~iiainien:~ncepur- atljustiiig thc rate of reciproc;itioti of tbc 1)latr. it is poses is of y$iiicli gauge. all of \v'hich sl~oultlpa>s n imsil~leto lieen the Kate oiirnitiys :ilmve thme limits. ?&inch scrceii. 'l'liere is, tlic.rcfore. little occasion for :I Friitii tlic griiplis it is l~ossil)le,for a iixt~lvol~mic of screen larger than tldi. \\'heti thr Ii1:rnt \vas Iiitrcliasetl lntch and ;I rlcfinitc iiiisiiiy licriod, to prel)arr otlicr tlie I I'j-iiicli ?crccii . tioii 1v;is niissiiig. ;inti for thr straight-line gralhs with size of opcnillg ag;iinst per- al)ovr rc;isoii. :iml aiiotlwi- nlliclr will I)c gi~etilater, l~as centage of batch. ancl by plotting these on one sheet not been replaced. Mav. 1933. MAIN ROADS. 127

In the original scrcctr arrangement, tlic matci-ial so that the buclict will always lie under the binder dropped from the scree'ns into a tlirce-coiiipartment bin supply outlet. of a total capacity oi 104 cubic feet. l'he individual After mixing-. the material is discharged from the capacities were %-inch, 21 cubic feet ; ?&inch, 21 cubic pug mill into a steel hopper, suspcuded under the mix- feet; and I%-inch, 62 cubic feet. A pair of liitlgetl irig platform antl over the vehicle loatling dock. With- deflecting plates have heen fitted untler the screens. out hand trimming, the lioppcr mill hold six tons. antl making the storage now normally available : 5/pinch. an additional ton may be stored if hand-trirnmd 21 cubic icet ; &-inch. 21 cubic fret ; atid ?+inch and The motor lorries arc Iiaclierl do\m the loading dock over. 02 culiic feet. Ti it he desired to use stone and under the loading hopper. the discharge gate of larger than %-inch gauge. this will he stored with the which is operated froin the mixing platform. Without Ti-itich screenings. and the relative proportions of the Icaving his seat, the lorry tlrivcr caii conimunicate by two adjusted, with due regard to their respective grad- means of a spcaking tube with the miser operator on itigs as supplied. at the proportioning icerler. Should the mixing platform. it be found desirable at any time. the I%-iiicli screen The machine is drive'n through gears and a clutch section can hc rrplaced. the largest hot storage bin by a 3o-horse-1m\ver Parkinson squirrel-cage intluc- can he readily tlivitletl. and an additional outlet gate tion electric niotor ruiuiing at (100 revolutions per provided, a'ntl then. by simple rnaiiipulation of the minute. hinged deflector plates. four gradings of aggregate can Armstrong-Holland Mixing Unit. -'The drier of this unit be stored separately. consists of two concentric drums, rigidly attached to To provide for possible future separate storing of one another, revolving at 139; revolutions per miriutc. four sizes of aggregate. an :2sco four-liearn aggre- The aggregates Iirst travel down the inner drum, re- gate weighing scale of a total capacity of 1.200 Ib. turn along the space hetween the two tlrunis aid dis- has been installetl. Thc capacities of the individual charge, dried aircl heated. into a chain-bucket elcvator. lieanis arc two of 400 Ib. and two of zoo lb. Tlw scale The hot gases from the furnace itre drawn hy a IZ>$ is fitted with a quadrant indicator atid pointer to facili- inch diameter mill-type fan. driven at 1.0s0revolutions tate arrurate weighing. The different graditigs of per minute. through the drums it1 tlie opposite direc- aggregate arc weighed separately into the weighing tion to the aggregates. The gases at presciit tliscliarge hopper a'ntl the batch tlieu dropped into thc pug mill. to the atmosphere. The weight of a batch of mixed material ortliuarily The heated aggregates are discharged from the ele- produced by this unit is. apliroximately, c8m lb. vator to a single storage bin niountetl over the mixing platform. Thc 1,ituuiinous material is drawn off from a coli- The batchilit. houi)er is susvcnded under the hot I, I. titiuousl!-circulatitig system by nieans oi a three-way storage hin antl over tlie pug mill, The batch is drawn cock. into a buckct suspcntletl from Xsco weighing from the storage bin by filling the hatching hopper to n scales of 90-11,. capacity. Tl~ebuckct is suspended in marked level. and is then tlroppetl into the pug mill. front of tlie pug-mill, into which the contents can be The hatch weight ordiiiarily produced by this unit is tipped directly. 1,000 Ib. Consideration is heing given to atltliiig an automatic A bitumen hucket is pivoted lengthwise over the tiller l~roportioticrantl feeder. For the present. how pug mill. and is filled to tlie level of an adjustable ever, the filler is proportioned volumetrically (the rc- pointer, attached to a scale graduated in half gallons. quiretl volume heing determined frotii the weight per The hinder is drawn off from the bitumen-circulating cubic foot) and atltletl Iry hand. To enable the filler system by rriraiis oi a three-way cock. to be readily placed in the pug mill. thc bitunren-weigh- The loading hopper and the rncthod of loatlirig into ing equipment is rnonntetl 011 runners and can he the lorries is the same as in the case of the Y'I ivcn pushed aside, but the nioveincnt has been restricted unit. 128 - MAIN ROADS. Vol. IV, No. 9. Pending tlie result of tlie trials with the oil burner in service, leaving tlic other as a stantl-by against oh tlie Niven unit. this miit is being hantl-fired with hreakdowti. solid fuel. On closing doiv~~tlic plant. all pipes are first drained. This unit is also tlriven through gears and a clutch Then, hy tiiaiiiptilciting tlie appropriate cocks. the by a Parkinson sqiiirrcl-cage intluctiirn electric motor kettles are isolatetl from tlie delivery lines, wliicli are nf, 3.5 horse-liower. running at 960 revolutioiis per then connected to :I 40-gallon tank of fael oil. The tiiiiiute. oil is circulated through the pipes for tivc minutes, Bitumen Heating Unit.-Tlic unit consists of four SOO- cleaning them tliorouglily. and is used sul~sequently gallon Ixttles :wtl two of 500 gallons inter-con'nected for paiiiting the insides of the Iiotlies of the lorries to tvitli z-inch diameter g:ilvatiisetl iron piping. Norm- prevent atllierriice of the iiiisture. ally. two of tlic Soo-plloti kettles ( Nos. I antl 2) will Heat Control.-The t\vo 500-~dlonliettlcs were fitted Irc used for innking-up. atid the remaintlrr for the when p~~rcliasetlwith Cambridge iiitl(.s thcremo- main supply. Tater it m;iy lie possilile to instal a inctcrs. 1\11 electric tlicriiiii-couple will I)e fitted into steam-heated unit. liut. for the present. availal>le port- each of the other four kettles. a Tliermis indicating al)le. hantl-tired equiliiiient is Iieing utilised. Each pyrometer erected :it ;I central point, and provision made by means of :I suitalile :rrrangeiiient of switches for connecting any tlicrmo-couple. as tlcsired. to the pyrometer. C'amliritlge atid 'l'ycos intlicating iiitlcx theriiiometers will be tittetl rcsliectively in the hot sand storage I~iiiof the Nircii uiiit ai111 in the hot aggregate storage Ijin rrl tlic Ariiistrong-I-Tollniitl unit. These instrunicnts ;ire for tlic control of teml)eratiirc:; tluritig mixing operati(rns. 'fhe iiiaiii I-rq~iisiteis that tliey should be easily reatl;ilile at a glance from a distance. For this i-mc~oiithe intlicating type of iii- strumeiit \vas preicrrcil to the rccoriling type.

07bnO.cm.m. larim " U Diagram of bitumen heating unit. r.I eml~er:itui-c rccortlers will IJC tittctl to c;tcli loa

Trrania Shire Engineer. N 1931, an alteration was matle in the boundaries Board shared in the project on the basis apl)ertaining of Lismore Miinicipality, certain areas being to ordinary roads at that time. I transferred to Terania Shire As a result, a scc- Foundations.~Esperience with prcvious 1)ituminous tion of the Li~iiiorc-n'inil~iiI-Murwilluinl~ahroad (No. pavernents on the road indicated that special precau- 142) \vas liantletl over to the Shire Council. This tions were necessary in preparing the foundatiohs. It section. I 54 milcs in Ictigth, had a water-bound maca- was found that, due, no doubt, to the nature of the dam pavement carrying heavy traffic froni thc closely- black soil, antl the continuons wct seasons which are settled dairying districts north of Lismore. Although frcquetitly experienced, the ordinary ruliblc suhgrade the road does not carry the greatest nuiiilw of vehicles. drains quickly becamc clogged. The water, which was it carries. in thc writer's opinion. the heaviest trafhc in able to percolate through and evaporatc froni the water- thr 12ichriiontl River district. In addition to cars antl bound macadam road, hecame locked in under the im- 'buses, heavy Inrries c;irryitig cream. butter. bananas pervious bitumen pavement and softened the founda-

I. SprFadinG I :-inch stone: ;-inch screenings piled readv for ore on shoulder-. 2. Spraying Tarvenac. 3. Mixing. the tractor conveniently straddling the mindrows. 4. Commencing the rolling. antl timber. arc constantly on the road. and there is still tions, causing considerable damage. For the mixed- a fair proportion of horse-drawn vehicles. From this in-place work. graded trcnches were excavated in the it can he understood that the maintenancc of the water- old pavement at inter\-als of 50 to IOO feet depending bound macadam was a constant drain on the Conncil's on thc situation antl the treticlies \Vere filled with broken funrls. The road frequently becamc a succession of stone and sand. tightly packed. :\ layer of sand. 3 pot holes and was at times a motorist's nightmare. inches thick, was then spread ovcr the old macadam ;\n agreement \vas matle I)ctween the two councils road. and on this a 4-inch thick water-hound macadam uliereby thc Municipal Council was to bear a propor- base cotirse \vas constructetl. Standard boxing (with tion of the Shire's sharc of the cost of the reconstruc- shoulder drains) \vas provided to hold this course and tion of the pavement with a tar or bitumen binder. the mixed-in-place surface course. The proposal to construct a mixed-in-place tar maca- dam pavement mas rccntnmended by the writer in an The alignment of the road is easy. except for one endeavour to provide a good riding surface antl also right-angle turn tiiade on a curve of 9') feet radius. as an esperiincnt to compare this type of pavemelit The gradcs are undulating, and include a sharp pinch with the penetration biturncn and tar pavemmt.; pre- rising atid falling a vertical distance of,approximately, viously constructed on the same road. The Main Road5 I jo feet on grades of S>2 and 8 per cent. respectively. 130 MAIN ROADS. Vol. IV, No. 9.

Mixed-in-Place Course.-The base course was swept (iii) The pavement stands up well to heavy traffic clean, and clean basalt metal, ranging from s-iticli to provitletl the foundation is sountl. Iz-iiicli gauge, was evenly spread to a depth of 2% inches. An endeavour was made to spread this course Costs.-Basalt of I>4-incIi gauge was supplied ant1 in two layers, consisting of Is-iiicli gaugc metal, cov- tlclivcretl on the road for 7s. bd. per cullic yard ancl ertl by %-inch to %-inch screenings. It was found, screenings for 8s. 6d. per cnl)ic yard. 7'arvenac was however. that better penetration and mixing n-ere ob- sprayed for IS. per gallon. The costs for the whole tained with the I%-inch metal alone, this material section of rg.yoo square yards werc: evidently containing sufficient fines. No. 2 tar (B.H.P. PFr sq ?(I. Tarvenac) was sprayed on the aggregate with the Coiistruction of mixecl-in-place surfacl. collrsr 1 withoiit sealin!) , , . , . . , . , , . , 2/3 pressure niacliine at the rate of galloti per l'ar scal emit . . . , . . . . , . . . . , . yard. Under normal working conditions a st - I I chains was laid daily, this length being suChcienr Siii-ixx coiirse complctc . . , , dzl for one tank of tar containing X4o gallons. Imiiiedi- The atltlitioiial 1)itumen seal coat cost :tpl)rosini:ttcly htl. ately after spraying. mixing on thc road was coni- per square yard 1)riiigiiig the total cost to 2s. Stl. per iiienced. using an S-foot blade grader drawn by a Fortl- square yard. soti tractor with caterpillar tracks. The 1)ladc of tlic _c_ grader was set almost parallel to the road antl very close to the base course. The metal and hinder were thus Hot-mixing Plant at Rosehill Depot-cmrtirrrtrd. well mixed along the blade and turned over into wind- ( Cotrtiuui9d fruiri /w!yr ieS.1 rows during four trips up and down the road. The General.-It is proposed to house the complete plant mixture was then evenly spread with the grader. over in one liuilding. a normal width of 16 feet. finishing the work with the blade almost at right angles to the road. The whole The switchgear for each mixing unit, antl also for operation took, approximately. two hours. The pave- one bitumen pump, has been groupell separately. ment was then cotisolitlatcd by rolling with a IO-12-ton each group a plug has been provitlerl for the attacli- power roller. nient of portable electrical apliaratui. '2 stop-button has Imn fitted 011 each mixing platform in order that The seal coat of No. 3 Tarvenac was applied in the the operator may stop his unit in case of eniergrncy. usual manner. generally within two days, at the rate of To indicate to an incoming lorry which unit to pro- ,?, gallon per square yard. and the paveiiient thoroughly consolidated with thc roller. ceed to, a single board indicator with a sliding panel has been attached in a prominent position on the mixing Results and Conclusions.--Some tifteen months Iiavc platform of each unit. Ry tiieaiis of the slitling panel. elapsed since the construction of the pavcmetit. 111 the a white background is shown to indicate that the lorry nleantinie the road has been under observation and has shall proceed to that unit. .I signal system wherehy received further surfacc treatinetit. the plant operator can communicate with tlie ganger As a rcsult of the grader finish, a good riding sur- without leaving his post lias also Iwen arranged. face was presented. The texture of the surface is The plant \vas tlesigned in the Metropolitan 1)ivision fairly rough. atid offers a good grip for horses. How- maintenance Iirancli ant1 erectcrl Iiy thc Dcpartiiient's ever. tlie wear from horse traffic antl heavy lorries was own staff. In planning the new portions of the in- very rapid. In about six months' time the seal coat stallation. advantage was talicn of much availa1)le was entirely worii off. Expcrimental seal coats of t/4 material from worn-out plant. e.g.. the new feeding gallon of hinder per square yard were then applied on elevator of the r2riiistrong-Hollantl miser was I)dt short sections, the materials used Iicing cold emulsions mainly from parts of the hot elcvator of anotlicr (two brands). hot bitumen (80-roo peiietratiirn') antl niachine of tlie same typc and of :LIJarIier-(;reene belt- No. 3 Tarvenac. The emulsions antl hot 1)itumeti type loader. proved to be quite satisfactory. tlie latter :ippearing to Personnel.-The personnel required to operate the give slightly tlie better results, clue. probably. to the plant is as follows:- greater pcrcciitagc of hitumen. The tar did not stand One plant ganger. .. well. The balance of the surfacc was then treated One leading hand to attciid to the unloading. elevating with hot bitumen at f/4 gallon per square yard. arid and distrilintinn of tlic inroming aggregates. . ' covered with screenings. and now gives every intlica- Two mixer (ipcrators. tion of lasting. Tlircc laliourcrs tn attend to greasing atid (iring. itnil to assist in thc imloadiiig of the aggregates. Should oil One cannot form general conclusions from an iso- tiring IK installed mi the .I\rmstriiiig-Hnllaiiil onit lated section such as this, but 1 consider that tlie iiitli- also, it is aiitiripatcil that only two lalwnrcrs will lie cations given Iiy this work are :- rcquirctl. -. (i) The method of mixing in place is superior Capacity of Plant.-The platit lias only just been to the light pciictration work \vitli which it erected and an opportniiity has not occurrctl to try it compares in cost. as a better riding surface out tn its full c-;q)acity. Outputs approaching roo tons is ohtainetl. per clay have been olrtainctl without tlificulty from [ ii) I

Construction on the Stockinbingal-Morangarell- Road in Narraburra Shire.

XI< Kr\BUKKA Shire Council has recently con- structed 3% miles of new formation and N gravel pavement on the Stockinbingal-Moran- garell-Marsden road (No. 23j j, ncar Morgangarell. The work is worthy of notice both on account of its importance as a new link in the road systcm of the district ccntretl upon Temora and because of its etlicieiit and cheap construction (f740 per mile). .I1 he new length of road comnicnces at the junction of the Stockinlringal-1orangarell road and the inipor- tant shire road known its the \\.intcr-roatl (which runs ill it southerly direction from i'vlorangarell to Tcmot-aj , and terminates at the junction of the former road with the Barmedmatl-h~oraIlgare~l-(;renfellfe~~tleveloplnelltal road (No. 1013j. The length of the work is 3 miles 1,045 feet. Ihe new road runs through black soil antl conglo- merate cou'ntry used for wool and wheat production. The grades are practically level. antl the curves are all easy. \llien formed, drained antl rolled, this country

Locality sketch. The new work is shown by a heavy line and the principal shire roads are shown dotted. 1. Typical view before construction. 2. The new road. 3. Curves at junction with Moranparell-Barmedman dcvelop- mental road. is fai rly sounrl. Light pavements will sufice because the heavy traffic occurs principally in the siniimer, and then the horse teams prefer to use the earth side- group of scttlcrs. the work has helped the locd unem- tracks. ployment situation antl has kcpt the councII's plant In previous years, the council has formed and engaged. gravelled the Stockiiibingal-Morangarell road to a The work cotisisterl of fairly heavy clearing., build- point 20% miles north of Stockinbingal. The next ing a standard Type ..\ forination 64 fcct wide antl 5 miles, on to thc junction with the \\'inter-I-natl. are from iz inches to z feet high above the natural sur- reasonably tratlicable in wet weather, so that the face, antl laying a ritlgr gravel pavement 16 feet wide settlers south of the junction have an all-weather out- and 4 inches thick. consolidated. As thc road here is let to the principal town. Temora. via the \Vintcr-ro;d on the sliglit waterslied Iietwcen I3lantl and Walladilly North of the junction, the settlers in the vicinity of Creeks, little crosdrain;ige was necessary. ( )ne gravel Mornngarell were formerly isolated Iiy inipass:tl)lc causeway, 300 fcct long, rS fect mitlr, antl z feet roads for from tlirec to five niontlis each winter. The deep. antl one a-incli diameter pipe culvert were built. cou'ncil therefore r.iatle a special effort to finance the The length of haul for the gravel was from 3:4 to present work. -4s well as relieving the isolation of a 6% miles. lhe total cost was f2.362 6s. Sd. I32 MAIN ROADS. Vol. IV, No. 9. Field Assembly and Erection of Steel Bridges.

[The following instructinn is one of a series prepared for the possibility of being splashed with Inutl. and in such the use of field oficers supcrintcncling hridge constrnction works bring carried out by contract, and is to IIC taken as a a position as hot to hold water ; otherwise the single guide to tlicm in carrying out their duties. It does not in coat of shop paint will deteriorate and there will be any M-ay overrulr the contract plans and specification. needless work in cleaning and repainting such members Others of tlie series, covering general matters, atid the later. construction of tinibcr and concrete bridges. will he pub lished in due course --Enr~nx.l For convenience both io traiisport antl erection, each separate part of an important bridge is marked with HI;, work of the field ofticer siiperiiiteiidiiig the its weight atid a tli~tingciisliing letter. conforming to T erection of a steel bridge coiniiieiices at the the marking plans and shipping lists furnished by the point at which tlie steel work arrives by rail fabricating shop. or sea at the station or wharf nearest to the bridge site. The fabrication or shop work, which has preceded the tlespatch of the steel from the workshop. affects. ho\vever, the erection methods which are to follow, atid coiisequctitly s~tiicunderstanding of the work in- volved in the preparation of the members for a steel truss bridge span is desirable before considering the question of field assembly antl erection. \Vhen the construction of the first truss of a new design is set in hand. tlie huilders tirst of all lay out the centre lines of tlir truss upon the shop floor. After checking all the dimensions against the plans. tcm- ~ilatesfor each piece of steel are preparerl. atid thence- forward hecoiiie the guides to the worlimeti who shape. rind bore the holes in the several components of each member of the trtiss. The tirst truss fabricated from a ticw set of templates is always erected it1 the shop. using temporary bolts in the conncctioiis. so that minor corrections caii be made to hoth templates :ind steel members. Small trusses are conimpilly assembled lay- iiig flat on the floor. but larger spans. comprising the pair of trusses complete with floor system and latcr:il (vi i) (viii) (IS) Iiracitig. are titter1 iti a similar position to that which they will occupy in the tiiiished bridge. Defective riveta. i. Head not in full contact. ii. Head split. iii. Soldier-cap ,\fter the first truss or pair of trusses lias been head. iv. Unfilled head. v. Metal wedged between assenibletl antl the templates checked and corrected. plates.... vi. Loose rivet caulked. vii. Head burned. ~i~~iallyno furthrr shop assrtiihliiig is perforiiietl. the VIII. Elongated head. ix. Eccentric head. iiiriiihers merely being inspected as to materials atid workmanship. atid compared with the templates as to Accuracy.-The substructure of the bridge tiiust I)e dimensions. Thus. mitior inaccuracies can possibly set out with accuracy, lest the piers or abutments escape the iiotice of the shop inspector. ant1 tlicre should not cotiforin to the tlimensions of the fabricated arises tlie necessity for sliilfully tittiiiK each spii superstructurc. Skew spans should be set out with erected in the field. special care. All tiieasuretiiciits should be made with Transport.-During transport from the point of tlc- a steel rape. and rigorously checked. For slmiis in livery (cg., railway station or wharf) to the bridge escess of 100 feet, a spring bala'iice slioiiltl be uset1 o~i site, the steel is under the care of the superintending thc end of tlie tape and all measurements taken witl: officer to the same extrnt as during the sul)sequent the tape at the same tension. antl corrections for sag work of erection. ~llthirughsteel is hard and tough. and temperature applietl. €'ossibly tlic niost valuable hritlge riicinhers may readily be injnretl Iiy carcless safeguard is to calculate the tliagoiial leiigths betweeti hantlling or neglect. Loading or uiiloatlin:. from tlie centres of the supports of each spati antl then vchiclrs. liftiiig. arid haidiiig in storage should there- tiieasure these tlimcnsioiis 011 the work. fore he carefully supervised. Heavy lifting asitli lmrs Erection.-In general. steel trusses are supported. or hatlly placed cahles. or tlroppitig on to vehicles or tluriiig asseiiihly and riveting, upon false work. The oii to hard ground niay spring heavy meinbers nut of outstanding essentials at this stage of the work are triie. or hetid or deform large gusset plates or the that the trusscs shall have the correct camher. that flanges of angle; or channels. Unless specially the iiiilletl joints in tlie upper cliords sh;ill bear tightly. approved otherwise. 311 rolled beams :ml plate girders aid that all the rivet holes in tlie connections shall iliust he transported and stored with their \vel)s stantl- register accurately. It is the contractc!r's responsibility ing vertically. ;\I1 steel must be stacked on skids p1;iced to erect the liriclge in accordance with the specitication. sulticiently close together on solid ground. remote from but thc superintending officer must checli carefully May, 1933. MAIN ROADS. 133

~ .~ each step (if tlic work so that unsatisfactory conditio~~s Bearings-The bearings should be fixed in position cat1 be brought to tlie notice of tlic contractor antl as soon as each lowcr chord has been assembled and rectified Ixforc serious difficulties arise. connected with temporary bolts and drift pins. 4n Tl~csuperintet~tling officer should check tlie levels acceptable method of fixing bearings is as follows :- of the camber blocks for the support of the trusses (ij Two steel strips, cadi z inches x $5 inch, slightly longer than the bearing. and having their upper faces at each panel point before any steel is erected. antl at machined. are placed on their flats parallel to each least weekly thcrcafter, and daily during the erection other, and as far apart as the liecl plate will alloiv, work on the span under consideration. Should the upon the ulqier surface of the pier or aliutment. blocks settle. or hecome compressed by their load, (ii) The hearing is placcrl in position, supported by the they should be raised to the levels given in the canibcr steel strips, and adjusted to its correct position Iry means of wedges under the strips. The follo\r.iiig diagram 011 the plans. Minur inaccuracies iw-hich points should he checked :- niny not be apparent to the shop ,inspector may cause Position.-The centre of the hearing should bear sett1emc:its at some panel points when the span is the eurscct selation to the bridge centre line. swung. Therefore. it is well to see that the members rlli~,rrii~ci~f.~Tl~elongitudinal and transverse ares of the bearing should be arcuratcly parallel and at ac tittctl together without undue strain or distortion. right angles. respectively, tu the bridge centre line. The canil,er diagrani must be rigidly adhered to, antl Ncduccd Leud-The hearing should he at the cor- any faults corrected before riveting is commenced. rcct height. ,. Plorie of Bcoritrg .Surfocr.-The bearing surface 1 he specilications require that all field connections should lie accurately in a horizontal plane. shall be drift-pinned and btrltetl before riveting may be After completing the adjustments, the strips and commenced. Tniportant connections, i.e., all truss and the hearing should be marked, so that the latter can floor beam joints, but not those in the stringers or he removed and replaced, when necessary, in the precise position it occupied during adjustment. (The lateral bracing, must have at least 50 pcr cent. of the under-surfacc of the bearing should he finished, if holes pinned with parallel-sided drifts, or bolted The necessary, sufficiently to give a uniform and stable proportion of bolts to drifts in any connection should hearing upon the strips.) be at least ~O:ZO,with a minimum of z bolts in any (iiij The hearing is removed, and the strips arc fixed oiic joint. All holes which will not admit a cold rivet permanently hy embedding them to the level of their upper faces in 2:1 cement mortar, the holes for the should be reanied until this is possible. Drift pins holding-down Iiolts being kept clear. draw the nienibers into tlicir proper relative positions (iv) .4fter the cement mortar has set hard, the hearing is anti maintain this until the rivets are driven. Bolts replaced in position. as indicated hp the marks upon hnltl the inemhers in close contact. so that there is no the strips, and the holding down holts are also placed in position. The latter are then fixed permanently in space hctween the plates while the rivets are being 2:I cement grout, either hy raising the hearing tem- driven. Careful tightening of these bolts is the hest porarily a few inches, nr removing it entirely and insurance against loose rivets caused hy the tlrivirig of maintaining the bolts in their correct position hy adjacent rivets, or the wedging of metal between means of a template. plates. (vj After both mortar and grout have set hard, the bur- face to he occupied Iiy the Irearing is flushed with a Alignment.-Kach span must he aligned longitutlin- coat of neat cement mortar, the hearing is lowered into ally, transversely and vertically before any riveting is position atid the holding down holts are screwed 1111 commenced. The following must he checked :- tight. (i) Alignment of luwcr chords. Riveting.-Rivets should completely fill the holes, (ii) .4lignment of upper chords. he tight, and have correctly shaped heads, conccntric (iii) Whether the two chords and thr end posts of each with the rivet holes. truss are in the same vertical Iilane. (iv) Whether the span as a whole is correctly located 011 Wherever practicable field riveting must be done thc centre line of the liridge. with compressed air hammcrs and the correct air pres- sure for the proper operation of the riveting haniniers The last-mentioned reqc~ircment is not essential must be maintained. If air is being used for founda- before rivcting is conimencetl, as a span may be moved tion work, or elsewhere, if tlic delivery main is long. without damage after the .riveting is complete. It is or there are other tools connected to the main between preferable, however, to rivet tlie span in its final posi- the riveting appliances and the compressor, the pres- tion unless the specification directs otherwise. sure should be watched with speclal care, receivers The alignment of the npper chord is, perhaps. uf thc being used where necessary. greatest importance, as this member is a horizontal Looseness is the most common defect in rivets. column which. if crooked or eccentrically loaded,. will Other defects, all of which are illustrated in the be stressed in a manner other than contemplated by sketches on tlie opposite page, are as follows:-- the designer. Rvcry butt joint in the upper chord. (i) Head of rivet not in contact with plate for its full ant1 between the upper chord and the end posts. should circumference. bear on its whole face. Millctl joints should not admit (ii, Splitting of head. cansed Iiy overheating and tlieii a feeler one-hundredth of an inch thick. driving too rolil. (iii) Soldier cap head. caused hy using a. rivet with too Such devices as jacks or lifting tackle. and the long a shank, which gives :L lip around the head. This loosening and re-tightening of the bolts in floor beam is not serious, iirovided the ri\.et is ti& and fills the conncctions, can be used to assist in obtaining correct holc. (iv) Unfilled head, caused by usinl: a rivet with too short a alignment, after which the riveting may he commenced shank. with a reasonablc expectation of preserving the ad- (vj Metal wedged hetween plates, caused hy riveting he- justment thus secured. fore the plates have heen drawn tightly together. 134 MAIN ROADS. Vol. IV. No. 9.

'Tllis is ilifficult to detcct. :md call only he d,viatcd 115. I'rior to commencing the field painting. all abratletl hwiiig all plates fat against the connecting incinber~ Iiy carefully tightening the crcction Iiolts. or tlamagcd arcas uf shop piiititiug. :mtl all tieltl rivrts. erection antl match marks and any areas of bare steel, (vi) Head of IIIOSC rivet canlked to C~JIIW~Idefcct (I) and to give appearancc of soinidticss and tightness. (Thia should he painted with red lead paint conforming to IS doiie Iiy tilting the riveting snap at an angle, or by the specification. Otherwise the length of life of the mans of ti. ciilil chisel a~)plicdto the lip of the rivrt field paint over these areas will bc rcilucetl at lcast head.) by half. (vii) Heads hurncd by ovcrheating. cawing hrittlencss. Sparks emanating from the rivet during driving sig- The ficltl coat of paint should not be applied until nify overheating. Sncli rivets may lie dctccted, even the engineer has inspected the preliminary touching whrn driven, Iiy thcir pittrd surface or the prescncr up descriherl aliovc, antl has signified that the struc- of Iicavy iron oxide scale. and sho~~ldhe removed ture is in a proper state for field painting. alii1 rcplacud. cvm if they are tight. (viii) Iilonxated head, caused by beinn driven too cold. All painting should be carefully examinetl for tle- (ix) Eccentric liixl. wliich tiiay IIC dctrrtcrl Iy measuring fects. A small mirror is useful for reflccti,~glight the distance Iic.twren rivets. or the distalIc.cn of eithcr into such places as the interior of an uliper chord dur- head nf a rivet from the end or edge ol 5 mmilirr. ing inspection of the painting. Rivets shoultl bc thoroughly exaniitied, tint visu- Expansion Clearanee.-Althnugli the fixctl end of a ally. then by tapping with a light stccl hammer, to :pan may bc crectetl as tight as possible against the tleiect looseness. In thc latter cases. a bare finger substructure, clearance at the frce end should be equal should be placed on the rivet head (if possible. the to the amount shown 011 the drawings (approximately opposite head to that being tapped) unless the person 1% inch per 100 feet of span) in order to give room making the test is thoroughly experiencetl in detecting for the expansion of the superstructure due to in- looseness from the ring of the hammer upon striking crease uf temperature, and the stretching of tlie lower the head a light blow. Defective rivets should he chord when the falsework is lowered antl the span marked immediately with a chalked ring, antl promptly is under load. It is, therefore. most important that removed and replaced. An occasional apparently the expansion bearings should he examined carefully sound rivet shociltl Iw marked for removal as a Gre- to ensure, firstly. that there is no hindrance to free caution. movement in the proper direction, and, secondly, that there is sufficient clearance to pcrniit the anticipated Rivets should be iiispectetl as driven. Thc riveting amount of movement. Neglect of this matter is coni- crews should be expected to remove any defective mon, but its importance can hardly he exaggerated. rivcts while still hot. without waiting for :i definite ortlcr. 011 the rlthcr hand. the superintentlitlg officer The groups of rollers or rockers supporting the free should inspect the riveting at each panel point entl of n span should be set so that the rollers are at I)roniptly. as it is most desirable to avoid the necessity the centre of thcir path, or the rockers are standing of the contractor having to ercrt scaffoltling twice in vertically, after the falsework has 1)een lowered, antl onc place. when the span is at a temperature of 40 degrees Fahr. (This teniperature is the average between the two cx- Rivets do not tighten with age. I,ut rather tend tn trenies of 20 degrees and 150 degrees Fahr. that usually work loose. One loose rivet in a ccmnection inay be applies in New South Wales.) If the position of the overlooked if the rcinaintler are thoroughly sound, as entl supports is finally adjusted after the span is coin- the ciitti:lg out of a defectivc rivet will often loosen pleteti and self-supporting. thcre is no neet1 to take others which previously had been acceptahlc and, in account of tlic stretching of the lower chord under any case. lieltl conriectiolls contain TZ,% per cent. more load; otherwise both the latter. and the variation in rivets tliaii shop connectiotis carrying an equal load. length due to the difference between the temperature to provide against the less perfect driving conditio~~s at the time of setting the supports antl 80 degrees Fahr. in the firld. must be allowetl for. If the span is self-supporting at Painting.--All paint shoul~llie sampled. tested and the time of adjustment. and carrying its full dead approved before applying. It should be examinetl load. the supports should be set off-cetitrc (in the particularly for rapidly-drying adultercints such as case of rollers) or iiiclinetl to the vertic;ll (in the case petrol. The paint should be stirred until it is of uni- of rockers), a distance of 0.07 iuches for single-faced form consistcticy frnm top to bottom of the container, rollers or rockers and half this amount for doublc- antl should I)e ~naintainetl in this condition always faced, per 100 feet of span per IO (legrces Fahr. tlif- when in use. Any skins slioultl I)e removed liro~nptly. ference of temperature above or below (80 degrees Fahr. if the supports are to be central (or vertical, as hinting shotiltl not bc pcriilittetl in wet or dusty the case inay be) at a temperature ai Ho degrees Fahr. weather. or when thc steel is damp, or when frosts If required the calculated variations in length of the :ire expected. The paint slior~ltl be Irushed thor- bottom chord inay be obtained from the engineer. oughly arountl all rivet heads atid into the interstices 1)cttbeeii plates. XI1 brush marks slio~~ltlbe worked Lodgment of Water.-The bridgc should be in- out. uutil an cven coat is obtaiticd. spected carefully to discover if there are any confil:etl spaces in the steel work. in which water, dust, or 2\11 parts inaccessible after fixing shoultl be chrckctl refuse from the deck or elsewlicre could lodge. All carefully to ciisure that these have recei\Tctl the speci- such spaces should be drained by holes, or, if this is fied nunilier of coats of ~iaintbefore nssctnbly, whether not feasible. fillcd with concrete which, when thclr- in the shop or in tlie field. oughly dry, should be sealed with hot bitumen. May, 1933. MAIN ROADS. I 35 Tenders and Quotations Accepted. The acceptance by the respective Councils of the following Tenders has been approved by the Department during the month of March, 1933:-

Work. Name of Amount of Shirear Road j I Description. Recommended Tenderer. Recnmrnenrled Tender. Xunieipalitp. NO.

Macquarie ... 2.13 Construction nf three-span timhcr bridge, 103 ft. long, over IT. Woodward ...... Curra Crcck. Rannockburn ... 12 Coristruction of four-cell, 9 ft. x 7 ft., concrete culvcrt ai \V. T. Addison ... rX m. 5.100 ft. Dcmon~lrillc .. . 24.3 Constriiction of thr pan concrctc bridge, 119 ft. long, I?. l.litchrll ...... over I>cmundrille Crcck. Yanko ...... 1108 Construction of six-span timber beam bridge. 180 ft. long, Bridge, Wharf CY- Gen- over Mirrool Crrrk. eral C.onstrirction Ltd. I%ellingcn ... 1134 Construction of four-spaP timber bridge. I28 ft. long, at RlcArthur, Andorson & Tyson’s Crossing. Simons. Murrungal __. 248 Construction of three-span concrete hridgc. 160 ft. long, State Monicr Fipe over Rooroaa River. Works. hiulwvarcc ... .3 Construction of concrctc lnjx culvert. j8 ft. long, and H. E. Ibbotson ...... approaches at \Tillow Tree Creek. South Grafton .._ 207 Reconstruction of Bent-street in cement concrete, 2.777 State Monier Piuu lin. ft. Works. Peel .__ __. II Construction of concrete bas culvert, R ce!ls, j ft.x 4 ft., at \\’. Shaw ...... 25 miles from Tamworth. Roomi ...... 12 Embanked formation, .I m. 47 chs., clcaring, I m. hg chs., A. R. hlcPhie ...... and three causeways, between 21 and 34 miles. Boomi ...... I 2 Embanked formation, 4 m. 25 chs., clearing, 4 m. 27 chs., 4. R. 3IcPhie ...... and two causeways. Sundlr ...... 1) Construction of eleven concrctc culverts and approaches J. h. Shaw ._. ... bctwvcen 106 and 22& ni. from Tamworth. Coonahnrab:-an .., 11 Earthworks and gravel pavement between Coonabarabran Ihrlcy and T.rwrrs . . . and Toorawrenah, 2 miles. :\psley ... __. 11 Construction of two timber beam bridges over Tiarra Creek J. White ...... (+oft. long), and Dlackfellows Gnlly (51 ft. I ong). respec- t ire1y. \Veddin ... _.. 1110 Supply of 950 cub. yds. of gravel and construction of 3 31. P. Smith ...... 175 o o causeways between 11 m. .to chs. and 13 m. 50 chs. lhrrigo.,, ... 151 Reconstruction in tar prnrtration macadam, with bitumen Bryant R- Iluch~~nan 6,691 13 2 seal, from Pacific Highway to Coll’s Harbour jetty, I m. Ltd. 3,720 ft. Blayney ... .._ 6 Forming and gravelling of Hrd Hill deviation, 3.G80 lin. ft, L. L)e la Torre ... I3oolooroo ... 0.3 I’orming and gravelling, I$ milcv ... .__ .._ ... F. Rakon ...... Harwood ... IO Reconstruction in bitumen penetration macadam from Murray & Co...... Harwood Ferry towards \Voodburn. I m. 2,800 ft. Kyoglr ...... 1141 lrormation and gravelling, I m. 2,867 ft. ... ___ ._. I;. E. Rown ... .._ __~__ The following Tcndcrs and Quotations were accepted by the Department during the month of March, 1933 :- Tenders.

V-ork. Of Accepted Muiiicipality or Name of Sur.ressfu1 Tenderer. Tender. Shire. I %td Description. I s. d. Erina _.. ... IO Supply and spraying of Uuratenax for rcscaling between Australian Gas T.ight 2,364 18 4 Hawkcsbury River and Mooney Creek, 43,660 gals. Co. ‘ralhragnr ... 7 Construction of 3 in tar penetration macadam surface A. R. Wheeler ... 644 11 8 course on Xarromine approach of hvacquarie River Bridge, Dubbo. I.ake Macquarie ... IO Supply and spraying of No. 2 tar for resealing betwccn B.H.P. Ry-Products 457 0 8 Catherine Hill Bay and Swansca, Iz,zjo gals. Pty. Ltd. Timbrebongle ._. 11 Construction of a timbcr beam bridge, 180 ft. long, over J. Jamieson ...... 2,151 18 6 Ewenmar Creek. 19%miles from Trangie. Talbragar ... 7 Construction of a timber bcani bridge, I20 ft. long. H. V’oodwaril ___ ... 2,070 14 o including formation and approaches. at Eulomogo Creek. Talbragar ... 7 Construction of two timber bridges, 90 ft. and 40 ft. long, R. Biggs ...... 2,594 1.3 G together with formation and paving of approaches, at Sandy Creek. \Veddin ...... 6 Construction of a concrete slab bridgc, 92 it. long, at Iron J. J. Piggott and G. I3yc 1,611 3 o Pot Crcck. and a reinforced concrete culvert, 50 ft. long, at Murray’s Creek. Mmilla ...... 63 Reconstruction in reinforced concrete of pavement 011 the C. Davis & Sons ... 1.919 5 0 Namoi River bridge, Manilla. 136 MAIN ROADS. Vol. IV, No. 9.

Tenders-cont inued.

Work. Name of Amount of Municipality R"ad Successful Tenderer. Acceptcd Tender. or Shim. NO. Description.

Stockton .... Construction of t\vo vehicular ferry docks at Newcastle and P. E. Olson R Sons . . Stockton. Kyeamba .... Construction of a two-?ell. I) It. s 8 ft., reinforced concrete Charles Hardy Contract bus culvert, and 980 lin. ft. of gravelled approaches at ing Co. Lid. McIntyrc's Creek. Cundagni Construction of 7 ft. x 4 ft. rclnforced concrete culvert, and John Gamble and I<. A zoo lin. ft. of approaches, at 4 IF. 3,900 ft. from Hume Olisr. Highway. Timbrebongie an Erection of timber culvcrts. labour only- Marthaguy. Section I ...... Stan Craig ..... Srctions 2 and 3 ...... F. Charles ..... \!'ami nph Hire of up tr, four ,-ton trucks, fitted with pneumatic tyres r J. W. Ward ..... an4 pou.cr-opcrated tipping gear, fnr regiavrlling be- 'I. Higgins ..... tween Rosrville Uridge and Beacon Hill, prr hour. H. H. Moorhonsc .. JohnSims ..... Jamberoo Hire of up to six 5-Lon trucks, fitted with pneumatic tyres J. H. Moore ..... and power-operated tipping gear, for Kiama-Jamberoo I I<. E. Kapier ..... reconstruction. 1%'.A. Smith ..... Quotations. Amount of PO. of Vescription of Artick, Name of Successful Tenderer. Accepted Quotalon Quotation. L s. d. 308 1.iquid bitumen, far. Campbelltown, in drums. 5s tons .., .4tlantic Union Oil Co...... 638 o o

324 Precast concrete box~~ colvert., f.n.r.~~ Sanileatc. ~~ 2 ft. 0 in. wide State Monier Pipe Works ...... I ft. deep, j: lin. ft. 325 Reinforcing stid, f.u.r. Singleton, 27.2 cwt...... State nhnier Pipe Wcrks ...... 32" I3rokrn stonr, f.o.r. Bombo, goo tons, in.; goo tons, 2 in. ._. New South U'alcs Governincnt Railwa: 3'8 Reinforcing stecl, f.0.r. Coolac, 52'3 cat...... State Monier Pipe \Yorks ...... 1329 Hituniinous emulsion. delivered to Parramatta-road. ouuositr Emoleurn, .inst., 1.trl...... 1)odge Park, in drums. 3,500 gallons. __ 330 Reinforcins steel, f.o.r. Gunning, LZ cwt...... State Monier Pipe Works ...... 33' Crushcil gravel, f.n.r. Richmond. 3 in., 2,234 tom; ,$,;in.,931 ton: Nepean Sand & Gravrl Co. ... 3.3' Crushed slag, f.0.r. Morandoo, $in., 58: tons: T,, in., ?so tons _.. B.H.P. By-Products Pty. Ltd. ... 33.1 Bridge timber. drlivereil to the bridgc over the Hunter River ai I<. -4. Sweetman ...... Dcnman, 14 in. x 14 in.. 26 ft,; 13 in. s I2 in., 57 ft. 6 in. IO in. x 4 ill., LI ft. ; Q in. x .I in., 42 ft.: X in. x 4 in., 63 ft. ; 6 in x 4 in., 164 It.; 6 in. dia. at small end, 185 ft. ; 4 in. thick, 7-10 in. wide, in 18 ft. 6 in. lengths, 3,joo sup. ft. 335 Bridge tirnbcr, delivered to I.ower \\ybong bridge site, K. A. Sweetman ...... 131n.x12in..11,5ft.6in.;i5in.x1o~n.,84ft.,~zin.x~zin., 40 ft.: 9 in. x (>in., .&Ift. 6 in.: 8 in. I 8 in., gjft.; 18in. dia. ai centre, I.+ in. small end, 8.i ft. 3 in. 33" Hriilge timbcr, dclivercd to Lower Wybonfi brirlgr site, 4 in. K. A. Sweetman ...... 111 I, I thick, 7-10 in. wide, 17 ft. 0 in. IcngUis, 7,8+o sup ft. 337 liridge timber, ilrlivererl at Minnamurra bridge, 15 in. x 21 in., \\. \\att 8z Son ...... 58 11 o 7 ft, 6 in.; 15 in. x 15 in., 5 ft.: 12 in. x 15 in., 56 ft.: y in. s IJ in., 48 ft.; I in. x IL in., 76 ft.; IS in. dia. at small end, 38 ft. 338 Ihag scoops, 5 cub. ft., \+ill1 lmrs, 36 only ...... Armstrong Holhntl Ltd...... 330 Hrokcn slag, f.0.r. Blorandoo, 1 in., 282 Lorn; p,Tin., 126 tons ... 13.H.P. Ily-Products Pty. Ltd. ... 3-10 Tar. f.0.r. Bornailerry, Heavy Priming. 1,loo gallons; No. 2, North Shore Gas Co...... 1,380 gallons. 343 Broken stone- ... F.o.r. Prospect, ,:. in., ,,.io0 tons; 3 in., r.po tons ... N.S.W. Xasouated Rluc itletdl Quarrir: P.o.r. \Videmere, I:., in.. 2.5oo tous; 1 in., 2,500 tons ... Sydney & Suhurhan Blue Metal Qnarri 346 Concrctc pipes, f.o.r. Ikxambola, 36 ft. x IX in. din.; 1g6 ft. x Rocla I.td...... 21 in. dia.: 2.1 j ft. s '4 in. Ilia.; 12.5 ft. x join. dia. 345 Iiitumen, f.o.r. Kiama, Oo/jo in wooden barrels, 250 tans ... Shell Co. of Aust., Ltd...... 347 Stecl reinforccmcnt, f.0.r. Coolac. 7l.9 c.wt...... Aquila Steel Co...... 348 T3rirlgr timbrr. f.o.r. Sorth (;oolagcng. 18 in. dia. at head. 1.1 io. R. Hargrnsr ...... at ti=, 24.5 ft.; IY in. din. at centre, r6 in. dia. at small end, 207.3 ft.; 13 in. x 12in., 441 ft. .I in.: 4 in. thick, X-IO in. wide, in 2o ft. lengths. 1.600 sup. It. 349 Gunmetal hriilge namc-platcs. 50 flat, 60 curved, with screws ,., H. C. I.indcr ...... 350 Grader, horse-drawn, 6 ft. blade. weight 1,Ooo Ib.. one only ... British Standard Machinery Co. ... 35' Cnncrete pipes, f.0.w. ~lladulla,168 ft.s 1.5 in. ; JL ft. x IS in. State Monier Pipe Works ... 35' Hrokvn stone, f.0.r. Bombo. in.. ooo tons; p6 in., 4.50 tons .., New South Wales Government liailwa! 3.54 I3itnminous emulsion, f.0.w. Tathra, 2,UL.i gallons ...... Emoleurn, Aust., 1.td...... 355 Iteinforceil steel, f.o.r. IIolbrook, ~3.15cwt...... State Monicr Pipe \Yorks ...... 356 Concrete pipes, f.o.r. Holbrook, I1 ft. x IX in. rlia Rocla 1.td...... dia.: 8 ft. x 24 in. dia. ; jo ft.x 30 in. dia.; 68 ft.x 36 in. dia. - Sydney: Alfred James Kent, I.S.O., Government Printer-19Sa.