Improvement of Road Pavements on State Highways.

Improvement of Road Pavements on State Highways. THE map on pagc z illustrates the nature of road pave- ments on the State Highway system as at 30th June, 1936, and shows also the pavement improvetlient work inclutletl i n the Lkpartmcnt’s worlcs programme for the current financial year.

I t will he notctl t h a ~ on tlie two principal inlantl routes. viz.. Hume I ligliway leading from Sydney to MellJournc, ;itid New Ihglancl Highway leading from Pacific Highway near Newcastle to Brisbane, together with the section of the I’acific Highway between Syd- ney and Newcastlc. the ~~rovisinn of modern dustless surfaces is no\v wcll at1v:mced. Sydney and Canbcrra are already linlted hy chistless road pvcmen t through- out. a distance crf 190 miles, and at the end of the current financial year only some 31 miles out of a total distance of 375 miles betwccn Sydney and Albury will be unfinishctl o n the Hume 1-Iighway. The out- standing sections co~nprisctl in this length mainly re- quire costly re-location. ancl finids cannot at present be allocated to deal with them. It would be in- aclvisable, Ilowever. tu provide a modern surface on these existing- locations. as this would inevitably give rise to higher traffic speed which would bc unwar- ranted on account of the narrowness and indifferent alignment 011 these sections.

Steady progrcss is also being made on the other principal State Highways in the State. O n the Prince’s Highway, serving the South Coast ant1 providing an alternative route to the Hume Highway to Melbourne. a dustless road pavement has been provided to a point 29 miles south of Nowra and 131 miles from Sydney --with the exception of a length of 6% miles, betwee? Kiama and Berry. On the latter section it IS antlcl-

*8506C-A

pated that 4% miles will be constructed and, paved during the current linancial year, leaving approximately 2 milcs requiring construction, where a <eviation is proposed. More rapid progress on this highway has hccn impossible owing to the nature of tlie country passed through, the narrow width of long stretches of winding road all calling for relocation or widening before carrying out the construction of pavements \vhich must tend towards greater speeds and conse- quent increased datigcrs and risks. The Department is concentrating on making the road safe for higher speeds. and much work of the reqnired character has been done and is at present in hand. On the North Coast, the l’aciiic Highway has been paved for a con- tinuous distance of 136 miles from Sydney, whilst 011

the New England Highway the surface pavcment ex- tends to Singleton, I 56 milcs from Sydney. Betweetl Singleton and Glen Innes, a distance of 264 miles, a dustless pvenlcn t extending in various sections over 168 miles has been provided to date. ’I‘hus in a dis- tance of 420 miles hetween Sydney and Glen Innes the highway has been surface treated for a distance of 324 miles. The Great \\‘estern Highway, which. with the North-western Highway, serves the central and north-western portions of the State. has been paved to Bathurst. 132 miles from Sydney, whilst the Yass- Canberra Highway. with a length of 23 miles between Yass and tlie Federal Capital ‘Territory boundary, w ~ l l he completely paved early in 1937. Shorter lengths of new improved surface will be noted on other State Highways.

A feature of all pavement improvement work being carried out on rural sections of State Highways is the universal adoption of “luw-cost” types of pavement,

MAIN ROADS. Vol. 8. No. 1 . 2 -- - _ ~ _ _ ___-~ ~

__ -

z ffi w E m w 3

.._.__.._..-.

3 -

November, 1936. MAIN ROADS.

Ten years ago there appeared to he every indicatioii that the State Highways would be used by steadily increasing numbers of heavy petrol ant1 stean-driven vehicles with solid rulher tyres, requiring Iicav!- and costly pavements. Since that time. however, pneu- inatic tyres have come into almost univcrsal use for heavy vehicles, legislatiun has restricted the range of econoniic use of heavy vchicles, and an ordinance gov- erning loaded weights of vehicles has heen proclairnetl. These factors have entirely traiisformrtl main road traffic conditions in h-ew South \'Vales so far as road construction is concerned. antl have enabled concen- tration on relativrly cheap forms of construction.

The prevailing type in new work is the bitumen or tar surface-treatctl gravel pavement. Constant atten- tion to thr developinerit of the technique of sui-face-

treatment work, the introduction and LIX of modern mechanical plant, antl experimetital work in field and laboratory. have etiablctl the Departrncnt at low cost to produce ri)atls of this type having a dcgree of smoothness ( riditig quality) equal to that obtained by mor? c o d y methods. while yet presenting a non- skid surface. Maintenance of roads of this type com sists niaiiil!- of resurfacing at intervals of ahout five years. As in the case of all "lowcost" roads, however, there must I)e constant vigilance in respect of minor surface Ixeaks ii maintenalice costs are to be kept to ;L

minimum, antl on this acccount s ~ ~ c h lou; cost surfaccs can only be utilised to advantage where the road author- rity is preparccl to provide and equip a properly trainer1 maintenance organisation, for there can he no relaxa- tion o i maintenance attention.

Permanent International Association of Road Congresses. The Permanent International ;Issociation of Road

Congresses was founded following a Congress of In- ternational Road Representativcs held in I'aris in 1908. I t has the objcct o t pronioting progress in the con- struction and maintenance of roads and the handling of trafic. The Association keeps itself informed of the latest trends and practices hoth in finance and adminis t r&m and in construction methods and the m e of road materials. This information is snni- marised and niatle availahle to members who may also pursue inquiries through the IIead Oftice of the Associatioii4ocated in Paris-or through National Committees which liavc heen set up in the various countries affiliated with the association.

It is the custom to I i c ~ l t l a world Congress of niem- bers each four years. the past three having met at Milan ( 19a6), iVashingtoti (1930) and Munich (1934) respectively. At these Congresses those who may speak with authority concerning their countries are hrought together to exchange views and learn of dc- vcloptnents. Questions of outstanding general interest are discussed atid papel-s read; the details of the dis- cussions, as well as the conclusions reached, being pub- lished for tlic inforimation of all members.

The Association pnl~lislics a hi-monthly bulletin (in 1 French, Gcrman and English), wliiclli records the activities of the Asiociation between Congresses and also contains information conccrning important varia- tions in road practice or legislation in the several couii- tries. The bulletin also contains for the information of memhcrs a bibliographic index to the latest publica- tions and reviews o i subjects of technical and general interest.

The Association is financed largely hy grants by Governments of nicmher countries. These arc sui>- ported by subscriptions of nicnibers who are divided

"I

broadly into two classes. The first group is known as corporation nietnl,ers, antl etnhraces such bodies as Public Departments, Chambers of Cot1imerce, Muru- cipal antl Shirc Councils. Scientific Institutions and commercial firms or companies. 'l'he second group in- cludes the individual private members who may join as permanent nlenlbers or as temporaly members for the duration of a particular Congress.

The subscriptiuns to the .issociation are as follow :-- r\nnnal Suhcriptiotl.

Francs. Approx. Aus- tralian eqiiiv;i- lent 30/6/36.

f s. d. Corporatioii (entitled tu one repre-

sentative ;it cach Conjiress and to all puhlications issucd) . , . . . . JWI I 13 4

Corporation ( fur recript of pulrlica- tion only) . _ . . _ . . _ . . _ . . . . . . i o o 16 8

Private memljcr (rntitlcd t o attend C o n ~ r c s s ancl recrive all p tions)

snl)scription for lifc nieml)ership .im 8 6 8

. . . . . . . . . . . . . . . . . . 23 o s 4 Private rncmlier-payment ol onc

The Kational Committee in Australia is known as the Australian Statcs Organising Conlmittee o [ the Association, antl meets each year at tlic same time as the Annual Conference of State Road Authorities. The Australian (Cotntnittee would urge upon readers the advantages of nienilicrship of the Association, the subscription to which, as will IIC noted above, is a nominal annual paymcnt.

Pornis of enrolment in the Association and any further particulars may lie sccured from the Honorary Secretary to the Australian States Organising Cotn- mittee ( M r . A. E.' \\arl,nrtotl): 3 ~ 9 C:astlereagll- street, Sydney.

I

~. - MAIN ROADS. Vol. 8, No. I . _ _

Development of the Upper Valleys of the Clarence and Richmond Rivers.

Construction of Developmental Road No. 1050 between Baryulgil and the Tenterfield-Casino Road (Trunk Road No. 64).

Tlic construction of a new road along the eastern side of the Clareticc River from the Tenterfield-Casino road (Trunk Koatl No. 64) southerly to Kungnrraha Creek lias now been completed. The work was under- taken hy the 1)cpartnient :is a continuation of the tle- velol)niental road construction carried out in the Upper Clarence antl Ricliniontl River Valleys during the period T C ) ~ Z - I I ) ~ ~ . :in account of which has alrcady been pulilishcd in ildai~t Rands (Xngnst, 1935 j . The con- struction. of tlie leiigtli in question marks tlic coinple- tion of a comprehensive scheme of road construction commenct~tl by the h h i n Ro:itl< Board in 1926. which had for its objectives the povision of the essential means of access i n an area of upwartls of I,MX),OOO acres of nnrlcvelopetl country and tlie linking up of the main road system i n the northcrn part of the State.

l'rior to r i p 6 this area Ii:.tmecw Grafton antl the Queensland 1)order was witii,>at any trafticable roads excepting thc ~l'ct~ter~ieltl-Casii~o road running cast and west through the centre ( 'l'runk Road No. 64) and a length of about 50 miles fwin Grafton to Baryulgil (Main Road No. 150). 7:lie Tetiterfieltl-Casino road supersetled in part an earlier road f rnin 'lenterfield to the coast which f r h w e d :!le route of the present road to a pciint about 4 mile.; east of Tabulam, and

proceeded thence in a south-c:tsterly direction to the Clarence River at Lawrence, then the port of ship- ment for the produce of nortllern New Ihgland. This road lost its importance many pears ago following the opening of thc Great Northern Railway tn Tcnterficld and of the road from that tonii to Casino. \Vith the advent of the North Coast Hnilway it fell into disuse altogcther and liecame untraflicable.

Up to the end of 19.34 the roads which had been con- structed under thc schcmc inaugurated in 1926 enibrac- ing a length of approsimate!y 12195 miles. are shown on map (on page 3 j by heavy black lines. The work was carried out mainly by the Main lioatls Board and Department in cxpenditure o f unemploynr~nt relief funds, and partly by Councils with developmental road funrls. Thc work described in detail in this article embraccs IS 111. 1.770 ft. of new cnnstri~ction, shown on map by firm double liiie ; about 1 miles between Kungurraha Creek and Di~bbadah Creek being the hatched sectlon shown on map, which Icngtli had prcviously been partly constructed-the work on this section conlprisetl the construction of ; h u t 2% milcs of gravel pavement ; the remaining section includcrl in the work was a length of I m. 1,440 ft. slmwll by crossed llatcliing on

1 Developmental Road No. 1050. Finished Work about 5 miles south of the Tenterfield-Casino Road (T.R. No. 64).

November, 1936. MAIN ROADS. 5

MAIN ROADS.

Developmental Road No, 1050. Finished Work 2 miles south of Tenterfield-Casino Road (T.R. 64).

map. the \York on which coml!iised the construction of culverts and drains. mitior rcgrading and gravelling. \\'it11 the addition of these leiigths. aggregating 23 m. \ ~ . Z I O ft.. tlie total Iciith of i~cmd completed under the scheme is ahout 14j miles.

In Novem1)er. 1934. a sum of f60,ooo \\'as allocated by the Uncinployment Tieliet' Council to complete the unconstructed length. A\ staff camp and depot were erected at Lily's or l'ooloonlii Creek, 6p2 miles south of the ~:isi i io- '~eli ter~el(l road Offices9 stores, etc.. were trmsferretl from the w m k s nearing completion between 13onalho and Woodmbong, and construction work W V ~ S cornnicncetl, mrlcr ur;etnployment relief coil- clitions UII 7th January-. I 93j. by two gangs working north antl south from the tle!iot By the end of Febru- ary, 19~35. 140 men were empl ryd , antl approximately this nutnher was niaintaiiietl t'nrougliout.

The country through which [lie road was constructed was un~lulating and hilly. lightly timbered and of sand- stone formation. Thc rn;irl did not follow the original surveyed route. and it was necessary to provitle for the fciicing o f the new road I)ouiitlarics throughout, Pcntling tlic completion of this fencing, gates ancl hy- passes Iiave Iieeti coiistrncted as a temporary measure where Iwuntlar!. frnces are intcrsectetl.

1 he construction I-rrovitled for a gravel pave111e11t 16 feet wide with shoulders 1 f.:ct wide. and for tinihcr heam bridges except in the c::se of the bridgc over Lily's Creek tvhich consists of a composite steel antl timber truss with timber heain approach spans. With the exception of two reinforced concrete box culverts

, .

Vol. 8. NO. 1 . - ~~

the larger culverts are of tiinher; the smaller waterways were provided for by reinforced concrete pipe culverts.

I he earthworks were carricd out mainly by SCOOP- ing where the material was suitahle and the hauls short. otherwise by horse and dray and hand-loading. One tractor was uscd on the work.;. and it was gener- ally eniployetl with a grade!- on the forming of the subgrarle. or in ploughing for the earthwork gangs. T n some cases it was possible to do light earthworks in sidelong country with thc tractor and grader. (;raw1 for paving purposes wa!, obtained from surface deposits by ploughing, haidionding and 1i:iulitig to the road Iiy lorries hired at th:: 1l)epartnient's stantlard haulage rates. The gravel was either it-on-atone or tlecomposed congloiiicrate and the deposits were such that thcy seldom extended more than a few fect below the surface. The haul dit1 iioi generally exceed al)out 3 miles. Consolidation. both cf the subgrade and thc gravel was carried out by t i 9 f t k in conjnnction with grading.

The tiniher for the culvert-, was ohtaiiietl by day- 1al)otir. from the areas arljaccn; to the road and was h:iuled hg a jinker attached to a 2-ton lorry. Timber for the bridges \vas obtained I)y contract. the round timber being sulqjlied from the timbered areas in the locality antl the sawn timber frnin local mills. Iron- hark was used throughout in the bridges. but i n tlie culverts bloodmood aiitl grey gmu were also used.

For concrete form work, use was made of the local tiinher.;. Carrabeen antl C'rah Apple. which were found to be quite suitable for the purpose. Gravcl and sand. for use in the concrett iinrk. were ol~tained from the Clarence River, screencrl ~ . n t l recom1~ine~l in the desired proportions. Reinforced concrete pil)es were supplied under contract.

The total quantities antl unit costs of the main items

* .

Ckaring and pruhhieg . . Earthworks .. . . . . . . , Catch drains .._ ... .., Tablr drainspitching ... . , . Pipe culverts r8; ... . , .

,, 24. ... . . Concrete in headwalls ... ... Gravel in pavement . . . . . . Fencing remowl and re-erection Timber culverts .._ .__ Timber beam bridgpr .._ Truss bridge over I.dv', Creek' Fender Posts .._ ._ _. ,

Concrete i n reinforced (roncretc culverts .. . . . . . , .

Kcinforcement i n h n x culverts

. . 21

*?re cwh. yd.

100 l in . f t

li". It.

cub yd.

IOU lin. I t . cub. ft. iin. I t .

earl,

rub. yd. C " t .

I t is estimated that the tut:ii cost o i the \York will be f48.425.

[he bridge over Iily's Creek, owing to the size and nature of the stream and the long debris which is broiight down by floods. \vas tlt4gnetl ancl constructed to provide a clear waterway in thc centre of thc strcam of 70 feet. The bridge cotlsists of a p f e e t coni- posite steel and timber truss span with :I timber beam approach span of Z j feet on tlic soutliern end and I j

- 1

MAIN ROADS. 7 ~~ ~

November, 1936. ~

Developmental Road No. 1050. Bridge over Lily's Creek.

feet on tllc nurtliern eiitl. 'l'he bottonl ChIJrd of the truss is of built-u11 stccl scvtinns. The remailldcr of the trnss members. with the t\rceptioii of the suspen- sion rods, are of dressed ironbark timber. The floor system comprises hemn ironbark cross girders 15 in. s 12 ill. atid stringers I I I .. in. s 11 in, with spiking planlis and 5-in tlcckitlg. I IIC piers are of reinforced concrctc and consist of uctagoiis at 19 feet centres, on footings 4 f t . x .+ ft . s 2 ft. deep and braced at the top with a 1)raiii E fcet 3 iilchcs in depth. Coffer dams were necessary fo r the foulldation work. and these

were cunstructrd of 6 in. x 2 in. T. arid G. hardwood timber fitted round frames of 6 in. x 4 in. hardwood and driven tlown as cxcavarion proceeded. A 3-inch centrifugal piinip was used to cope with the water flowing into the coffer darns.

F'ountlatiotis were carried iriro sandstone rock, which was I I feet and 22 feet respecti\-ely below ground level, and 5 feet and 16 feet respectively below water level. Concrete for the section below ground level was de- posited through openings i n the form work and taken down by means ~i chutes erected in spiral fashion

~

Developmental Road No. 1050. Cuttins 1 mile south of Tenterfield-Casino Road (T.R. No. 64).

Vol. 8, No. 1 . _- 0 MAIN ROADS. ~ _ _ ~ _-

;irountl thc coffer dams. The abutnients of the bridgc were of driven piles.

This road is now opcnetl til traftic throughout. antl only works such as lioundary fencing and minor items ~.eniain to be conipletctl. M i d i valuable land. hitherto practically isolated is now provided with access to coni- niercial centres. Besides pro:iding access to contitry within tlie Clarrnce Valle\r it will I)c noted that bv

provitles for more direct mail communication between Grafton and Tenterficltl. T I I addition, it completes a through road connection l,etw.c>en Grafton antl Bris- lxine. which will serve as an ;dtemative to the Pacific H i g h a y antl will be practic:tlly free froin the risk of interruption by flood.

The distance from Grafton to Brisbane by this route is about 20; i d e s as mtiil):ircitl with 221 miles

linking up with the Tenterheld-Casino road. this work by the I’acific Ilikhway.

Interpretation of Tests of Bitumens. A mscKrrmox of the lalioratory tests on bitunien to determine its suitability for particular purposes was piilAislie~l in Maiii Rands in 1929. Volumc T , No. a. Since then fnrther knowledge of the properties desir- able in hiturnell to ensure satisfactory results in prac- tice has heen acqnired, both in the laboratory and thc field, antl consequently the 1936-37 specification for ~mietratioti bitunicti is lieing revised and tests as anientletl thercin will be as follows :-

( r ) Frrc frorri TVut,.r. t r r d Foauririg.-To avoid possihle danger in use. bitumen must be frec from any ingredient. such as water. which is likely to came foaming or boiling-over when heated. I t is therefore specified that foani- ing must not occur below the temperature to which the material is likely to be h a t e d in the field, and a sinal1 quantity is tested to ohservc whether this is romplietl with.

( 2 ) Spccific Gruvity.--Ritumen is added to the road either at the rate of gallons per square yard of surface, or gallons per cubic yard of mixed material. I t is purchasetl by the ton. I t is therefore neccssary to linom its specific gravity i n order that pnrchase antl application may be correctly arranged. In addition. specific gravity a lw serves a nicatis of identification, as the various 1 inens on tlie ninrliet have inorc or less well tlefiiied limits in this respcct.

(3 ) Pctzctvnfiar~.-~rhis is a convenient test for measuring consistency within a limited range of temperatures. It expresses in degrees. each of which represents I/?jo of an inch. the depth t o which the point of a stantlar~l needle when placed in the vcrtical position atid loaded with a certain weight, will pene- trate into a sample in a stipulated time. the sample during the test heing at a certain specificd temperature. Three tests are to bc made on each sample under the following conditions of temperature, weight, and time :-

( a ) 2 degrees C. (35.6 degrees F.), 2 0 ~ grams., 60 secs.

( b j ’5 degrees C. (77 degrees F.), I O O

( c ) 32.3 degrees C. (00 degrees I?.). 50

From the results of this series c i f tests. i t will he possiihle to gange the susccptil)ility of tlic sample to teniperattire cliangcs antl so assist the field cngincer to anticipate thc 1x01)- ahlc bchaviour of the bitumen throughout the different seasoiis o f the year.

(4) Dur-tilit~~.-‘l’Iiis c1i;ir:icteristic is :I measure 01 a bitumen to espand :nid contract without breaking and cr,tcking. :inti. thcrefore. ititli- catcs its cohesive strength. lhctiliry is testeil by drawing spwimens o f fisetl crcm section at x definetl rate under water tiiaintaincd at either 25 degrres C. (77 degrees F.) or :: degrees C. (35.6 (legrees F,). The test at thc higher temperature indicates whether the bitumen has the rcrlnired ductility under aver- age conditions of temperatnrr, while compli- ance with the test at the lower teniperature is essential for succcw of application in regions where low temperatures occur.

( , 5 ) Soltibility iri Car-hoii 7’~lrirc/rlot.i~r.--Tliis test is a measure of the purity of a sample, and provides a nie:ins of detecting the presence of carbons. n-hich are rrgartletl as x sign o f over- heating during nianufactnre.

Since hitunieti is completely solulile in car- bon tetrachloride as wcll as in cai-bon bisu1.- phitle. which i h ; I volatile. inflamtnahle antl expetisivc re-agent with an olrjectionable odour. the use of the former is prefera1)le for determining supended inipurities. 111 usin;: rarhon tctrachloritle. wherc carlrenes occw, separation froni mineral impurities can hc inade su1)scqneiitly. i f necessary.

( 6 ) Solitbilily ;rr Pctrolcrirrr ;Vitp//fhu.-Iii the test for solubility i n Naphtha. the solvent hitherto specified has hcen “Petroleum Naphtha with gravity of 56 degrees Baume.” Thiire is diffi- culty in obtaining siicli fraction constant in

grams., j secs.

grams., 5 secs.

9 -

November, 1936. MAIN ROADS. --__ coniposition and i n maintaining it so, which leads to variahlc rcsiilts. A new solvent has therefore Iieeu selected to a special specifica- tion controlling t l iP source. aromatic content. iliecific gravity. ani1 1ri)iliiig poitit raiigc witliin limits sutticiently ii:irrn\v to ensure tlie re- quired const;rncy i n coni1)ositioii.

’l’hih test is a 1iic:isure of tlie nsphaltcue~ present which. althougli soluble in carbou tetr:iclilori(le. ;ire iiisoluble in Ixtroleum naplitlia. :\sphaltcnes tend to give lwdy and coiisis:lciicq :is well a s CciiiCiititioiisiicss to the niatcrinls in \vliicli they occur.

( 7 ) ! ; / ( I . ~ I Poiijt-Opcii (.up.-Tliis is mcasuretl hy 1ie;iting ;I sample uiitil the vapours lihcr-

ated at its surface unite when a small flame is brought in coiitact with t h a n . The tem- perature at which this takes place. is 111e flash point. ant1 intlicatrs the 1-ratliness of the bitu- men to tleconipose by heat.

(SI I.o.i.i 011 Ilcatirlq j Hottrs at 163 1)egrcrs C.- This test intlicates tlir amount of evaporation at high tenil)er:itures and is a nicawre of the tendeticy of a bituiiien to lose its ductility.

( 5 ) ) Peiirtr(itioii tr t 2.j Dc!/rccs C. uftcr- Ifcotirrg. -This test is carried out in the same manner as ( 3 ) . on the rciitlual I)itumpn from test ( 8 ) . It is therefore. to some extent, a measure of tlie cuiisistency of the hitumeI1yat the time of its application in practice.

Employment in Transport. Following the census taken by tlic Corninonwealth

statistician in 1933, figures arc now available to show the occupations followcd hy thc people. Tabulations are not pet complcte in reipcct of such persons as motor lorry tlri\ er5 ~111cr:itiiig vehic1c.s owned hy manufac- turers or tlistrihutors and in some cases thoye e~nploycd in supplying translii~~rt uiitlert;ikitigs are inclutletl in other general Iieatliiigs. Sufticient informatiou is pro- curable, huwevcr. f i - i m the crnsus and pul,lisIietl re- ~ior ts to give a reasonalk idea uf the nutnher ciiil)loyetl in the various ioi-ms of transport and the rr1atii)ii het\vceti the tr:unsport and other industries. It shoultl I J ~ . exl)l:iiiic(l t h a t the statements set out in this art irk inclutle d l pel-sons whn may I)c regartled as Iireatl\vitincrs whether they are occupied as enlployecs (11- eniployers or working uii their trwn account.

The numbers engaged in the various formi of transport in New South LValc5 in 1933 were :

TKANSPORT BY I.AND- I<ailways . . . . . . . . . . . . Tramways . . . . . . . . . . . . Road Transport

Carting-in(lependently of any other industry ... ...

Carting for a particular industry l b a d a n d hridge construction

and rnaintcnance .. . . . . Motor garages, taxis, etc. ... Livery statdes and miscellarroous

Traiisport by water ... . .. . . . Transport by air ... ... . . .

Total engaged in transport ...

The relationqhlp between:the various transport groups may be shown as under -

T R A N S P O R T

._. 38,200

... R.ooo

i j . joo 40,ouo

10,400

Son %so0

75.400 ... I S , 5 O O ... I no

... 137,aoo

I WATER 1

I O MAIN ROADS. Vol. 8, No. 1 . I It will thus bc stwi that 50 far ;is cmp]oy~ncnt is

concerncrl thc transport industry is cii\.idcd about q ~ ~ l l y bct\wcn road transport and transport by rail and water. In orrlcr to secure a better pcrspcctivc, tion :-

however, it is ncccwi;try to sec how othcr occripaliuns provide a livelihood for employees and others engaged in them. Thc following statement shows this informa.

WATER, GAS, EI.ECTRICIT17, ETC., .\ND L.1ROURERCl U N I ~ I < I ~ I N I ~ I ~ .

l ~ l l l ~ , l ~ l N G . . . . . . . . . . . . . . . . . .

hllNlNG AND QUARRYING . . . . . . . . .

COMAIUNICATIONS . . . . . . . . . . . . . . .

RNTISKT.4INMEXT, SPOKT .\NT) 1< I<CI(ISATIOX

FISHING AND TKAP'PING . . . . . . . . . . . .

I'OKESTRY . . . . . . . . . . . . . . . . . .

I'ENSIONERS . . . . . . . . . . . . . . . . . .

1NI)USTRT NOT STATED . . . . . . . . . . . .

I . . 1

...

...

...

. .

__-

'Thc C C I I S ~ S rcsidts sliow that approsimately onc-half the peoplc depend upon thc carriings of the other half. Ihe figures show~i abo\.cL, therefore, indicatc that one

person in every nine rclies upon transport for 'L living and that this industry ranks fourth in thc gcncral schcmc.

I .

I I November, 1936. MAIN ROADS. -~ ~- ~ _ _

European Road Practice, Great Britain and France. Extract from Report by David Craig, M.Inst.C.E, M.I.E. (Aust.), Chief Engineer (Country).

Coizfiiiiicd froiii pi?!/? 155. “dlaiiz Roads,” AHyust, 1936.

Spraying Jets-(continued).

Discussions with engineers, contractors antl plant manufacturers with respect to spraying jets led me to the coriclusion that the ideal jet has not yet been made. Iletails of some of the types used are available.

( 2 ) liiird(,r Heiifcrs.- A very ei‘ticient heater in use hy man)- councils is

littctl wit ii tlouhle furnace and double cauldrons antl tubular hot flues for initial heating. ‘The esse’ntial feature of thc hcatcr lics in heating the bindcr in one cauldron to a certain temperature and keeping it flow- ing over a weir into the second ‘cauldron where it is brought up to the requiretl temperature ;uid drawn off continuously i f ‘nece

( 3 ) 2 Zyyreyitr J’pi~eirtlers or Gritfcrs.- A large proportion of the cover material is still

spread by hand, but ”gritters” are becoming popular. These are generally of two to five tons capacity and are attached to the spraying maehitie and the screen- ings or “grit” is spread immediately behind the spray. Many machinery nierchants supply these “gritters” all of which are more or less of a similar type. They consist essentially of a V-shaped box the width of the sprayer supported oii an axle with wheels each side and a small balancing and steering wheel liehind.

A rollcr fitted at the outlet with curved grooves or a revolving brush driven from the axle ciisures a uniform discharge. Details of the spreaders are avail- able.

(4) Portablc d ~ ~ ~ . r i J ! ~ Muchiiies,- Portable macadam mixing machines with and with-

out aggregate tlrying drums are in common use. Many different types are 011 the inarket. particulars of some of which I have available.

(5 ) Rol1rrs.-

roller with Diesel mgine. cating oils is stated to I J ~ not inure than 2s. per day.

rcsurf;icing work.

A popular roller now on the market is the 10-12 ton Thq cost for fuel and lubri-

Light 6-7 toils rollers are generally preferred for

( 6 ) Gruuu/ufurs.-

Practically all the crushing plants inspected are equipped with granulators to reduce the z inch to 3 inch broken stolle down to screening sizc and many \vel1 known makes of granulators are available. Screen- ings crushed from z inch to 3 inch stone arc geiierally

found to be more uniformly and cubically shaped than the screenings obtained from crushing of spalls.

In tie^ crushing plant installatiotls, vibratitlg screens in preference to rotary screens are now being fitted.

( 7 ) Geitwd.- Portahle E m i t /s i fy i>/g PIw~ts.

:\I1 emulsifying platlts i i i Britain are stationary and on inquiry I was inforlnetl that only a very few port- able pla’nts have been manufactured, hut I was unable to locate any of these.

Self-contained Iiower rammers are now in use for consolidation of earth in trenches. etc., where thorough compaction is recluiretl. They are capahle of operation hy any intelligent unskilled man and can be readily transported from point to point.

Hillhouse Quarries, Troon, Scotland. The r p r r i c s were inspected together with the up-to-

date crushing and mixing plants. There is an excel- lent face of whinstolle without much overburtien. Stone is loaded into waggons by stcarrl shovels, and each waggon is weighted before being tipped into the pri- niarp crusher which takes the largest si.w that the shovels can hantlle. I t then passes through the secm- clary crushers, :ind afterwards through the two cone crushers specially installed to convert all stone into fine aggregatcs i f so requircd. Stone is first graded into y2 inch a i d upwards to 2% inches. A11 stone

inch downward is passed through driers and then graded into $ inch. % inch, inch and inch with dust screened nut. Vibrating screens are used throughout. I h s t is extracted from all stone by SUC- tion at one slagc or another. Dried screellings, sup- plied to country clicnts, are covered in the trucks to keep dry and clean.

A portion of the crushed stone is used on the works for premixed tar macadam and a’ny mixture of the various sizes required can readily be obtained by tap- ping the various belt conveyors antl discharging on to a cross belt. 'lie mixed aggregate is then tlischargcd into a hopper antl automatically weighed. Three mixers each with double paddles, antl capable of mixing about 13 cwts. per batch, are installed. The required binder is obtained from any onc of a battery of storage boilers Iielow containing various hinders each one of which is connected up with a c o n i n ~ o ~ ~ receiver from \vhich it is raised by compressctl air to the level of the mixers. The misers are on a travelling frame and can he used oppositc any one of al,out half a dozen hoppers containing various graclitlgs of aggregatc.

MAIN ROADS. Vol. 8, No. 1 . ~ . _ _ ~

12

A separate unit entirely is used for the preparation of asplialtic coiici-ete. 'I'he output of the quarry is over 1,000 tons per (lay ant1 of the pretiiixetl tar i i ixadaii i plant jw tons per day.

l'reniixcd tar iii:ic:i(I;ini is snp1)lietl to any spccifica- tioii liut :I conitnon specilication at present is for the aggrcg;itc to range from inch to z;/L inch size with :I small I)crcent;ige rangillg from inch to % inch mixed with a tar-bitumen compound ('Fk-20) at the rate of S gallons to the ton :inti per cent. to S per cent. of stone (lust tiller ;itltletl. The tiller is a stone flour ovcr ISO mesh I)rel)ai-ccl I)y pindiiig on the works.

In the suniiiicr time when the stone is naturally dry. the 1:irgc aggregates are rrot pre-tlrictl h i t pre-drying is resorted to wlirn the stunc is wet, but the manager ciiip1i;isisetl that it is never mixed when hot witli l)iiider, but allou~etl to cool in the bins for at least 24 horirs. 'I le consitlers that one of the causes of some o f the failures is the use o f / t o / aggregate in the mixers. 'rhc stone is thoroughly iiiisetl with the lrintler before adding the filler which is sl)rinkletl over the material :IS it is mixing. ant1 tlie mixing is continued until the tiller is thoroughly incorl)oratetI, which will be ;il)out tloul)le tlie tinic takrn for mising \vithout the tiller.

\\'it11 ivages ;it roughly one hil l ing prr hour and bincler at apl)rosimatcly 311. per gallon :L premixed tar niacaclam is sulq)lietl delivered into trucks at Ss. 6d. ncr ton. Sucli material is bcitig trnckctl antl shipped to various parts of Scot1;intl m t l laid cold almost all the year around.

General Information.

On tlic new Cl:tsgon.-l~iliiiarnock road which car- ries 8.000 to IO.OOO tons of trafic- pet- ( I ; I J , it was noted that tlic road conncctiolls Iiave been staggered as far as practicable in the direction of traffic as follows :-

\\A

This form of road connection which provides for two simple connections in lieu of one cross road con- nection is now bcing advocated I J ~ some engineers in the interests of safety.

It \vas noted that i i i colnicction with new hy-pas> roatls around London. 1,eetls antl elsewhere. tlmt the land atljuining W;IS so1111 tdcen up by resitlences i i ~ ~ d i n

es ttie local tratiic h ; id a1re:itly tlevclopetl to a u c h an cstent that tlic original o1)jrct for which the road had been constructed \vas largely nullifietl. In order to pruvirlc iiJr this conringeticy it woiiI(1 appear that ne\v roads of this type should 11:ive sick tracks ior 1oc;il r i d t i c :incl ;i rem r;d pavement for the through trattic.

The new ~~ l ; i t i c l i e~ te r - I~ ive r~ ) (~o l road carries four lanes of rraltic with Itcrlrs on c;idi silk ;ind trees I~l;iiitetl about 3 feet from the ked) .\t tlic juiiction of all cross roatls tlin-e is ;I ceiitral 1;intl round which a11 trall~~c must turn.

In some cuunties of Scotlancl cottagr.~ are provitled for tlie permanent ptrolnien ;ind forenieii. In Ayr- shire. four-rooniccl Iionscs. brick ancl rough cast. have 1)ct.n erected at a cost o f f + x ~ each.

In niaiiy of the heavily trafficiml htrects. tlic iisc of tlressetl stone setts cotitinucs. 1 1 1 (;lasgu\v \vIicre these are extensively used. the cost is approximately 40s. per square yard. \\'lien 1)roprly l a i r 1 tlicrc is no m:iin- tcnancc for twenty-tivc p a r s . :cnd tlie minimum life is furty years. Setts with dressed .;urf;ices arc: lio\v used ;nnd the riding qualities of the paveinetit arc good. l f tlie stone is selected. the \Year is even.

Touching oii the qiiestion of slipperiness of asphaltic 1):ivements. it was stated that there is little trouble in Glasgow. 1 lie streets ;ire kept \vel1 washed :und cotise- quently no film of fine dust accrnniilates \\-liicli, when tlainpetl with light rain, is the iliain canse of slippery roads.

Many of the minor ro:itls in tiioinitainous country Iiave a pavenient I O feet wide only with passing places provided at aliont 12 to the mile and arc w 1nc:itctl that one passing place is visi1)le fi-om the one 0 1 1 either side and are sign-posted so that they can IIC readily picked up.

111 connection with Iiwting of lintlers. sollie etigi- leers ;idopt the practice of lieeping the lids nf lroilcrs o f f so that the lighter fractions will evaporate into the air antl not contlenscx o n the licl and run 1)acli into tlie binder, thus foriiiiiig a layer of thin volatilc Inaterial on top. In atltlition. the I)intler is stirred freqwntly to facilitate the process of 11c;lting ;ind t1Iercl)y reduce the time talien I U raise the l)intlcr to a given tctnl>erature.

Rituinen filled witli 50 l)er cent. of stone (lust and rcl-met1 tilled bitumen is now snp1)lie(l by sever:~l firtns. Generally it is used for special I)u1-poses. lrut it is con- citleretl to be excellent for a waling co;it 011 tar or biturninous pavcnieiit with ; I n open mix. It is claitncd that there is no tcixlcncy for it to flow or \vc)rk 111) to a smooth surface. antl at the same time it clisurcs a waterproof pavement.

111 Glasgow one Imvenieiit \vac ex:iiiiiiietl where 1% gallons costing 6;/;d. per gallon had been usctl to seal a tar niacatlam jnvcmcnt atld cleat1 r i incl1 &il)s were rolled in . The large stollci vet-^ I)osc(l "11 sur. face and iirnily lieltl in positioll by the tillet1 I)it[ltnen.

, .

1 I

November, 1936. MAIN ROADS. 13 ~ -

Filled Iiitnnien is prepat-et1 from bitumen from 6 j penetration to 120 ~ienetration and filled with stone dust passing 1s0 mesh in equal yuantitics by weight. Slate (lust is considered to niakc an excellent filler. The I)itumen is heatetl to 26ju degrees and poured into the miser with open mesli gates. The filler is gratlu- ally incorporated as tlie niisture is stirrctl. Tt is then poured into wooden harrels cement-\\.nshed insitlc.

Traffic Control.

It was tinted that at many of the important street crossings in all large towns, automatic time signals showing three colours, red. aniber antl green. were in use with escellerit rcsults. .4t crossings where there are a much greater number of veliic1c.s passing one of tlie strects than the other. and also at crossings where the traffic is not so heavy. the timc signals are giving place to tralfic actuated signals with time limits,

For thc control of pedestrians atid traffic :it busy crossings. petlestrian l:<nes are marked out eitlier by painted lines or insertion of steel studs across the street.

Traffic Signs. A feature cif the new regul;itions with respect to

signposting is the erect ion ~i “t\dvance” signs ahead of road connectioiis. I’ersonally. I fnunrl thme very useful when motoring through the country. Full de- tails of staiit1;ird trattic sipis arc given in the l’rovi- sional Rules xiid Orders, 1933, issued by the Ministry of Transport.

,\ttention is directed to “Major l<o;itl :Uieatl” sigil No. 17. Part I . on 1iage 16. and to “.\pl)roach t o junc- tion” Sign N o . 9. l’art 5 , on p g r 24. ( S c c illrtstril- tioir.)

I _ _ ~ ~ _ _ _ ~ ~ ~ ~~

J Standard Warnins Sign, Major Road Connection.

Rrscnrch ntrd ILi-pcriincntaI W o r . k , Pure road research antl the carrying out of field

experimental work are no\v separately controlled. Pure research is undertaken by the Department of Scien-

titic antl 11idustri:il Rescarcl? at Ilarniontlsworth by Rlr. li. l<atwn and assistants who devote their whole time to the work. while the field experimental work

Standard Advance Sign Road Connections. Number of Road given Prominence.

is under thr control of Mr. Turner. hfinistry of Trans- port. ’I‘he tlivisioti of work pu.sscsses many advaii- tages as well as disadvantages. but on the whole tlie arrangement has worked out quite satisfactorily.

A Iiontl Research Roarti has Iwcn formed to 1:iy tlown what research work is to be untlertakcn. A s zit present constitutetl, the I3oard consists of the Assistant Chiel I<ngineer. lioatls Del)artment, Ministry of Trans- port as cllairrna~~. with three engineers representing T.ocal (hvernnient .\ntIiorities, tive Professors of En- +cering from v:~rious Universities. and two represen- tatives of ’Tar atid ~ i t u n i e n :\ssociations. two cngi- fleers from the Koads I)ci)artnient, RIinistry of Trans- port, and two from the 1)epartnient of Scientific and Industrial Research with assessors. The assessors are the technical advisors of the Roartl and they examine all results obtained antl draw up a report thereon fo r thc consideration of thc Hoard itself.

An l~xperimental \Vork and Highway Techniyl Committee has also been fornied. again with the i lss~s- ta’nt Chief Engineer, Roads Ikpartment. Ministry of Traiiqiort as ch:iirniat~. with seven other inenibers, two of whotii are oficers of the Ministry of Transport, two Local (;ovcrnnient Engineers. one representing outside interests, one I’rofcssor of ICngineerirlC. ant1 the ofticer controllinr: the road research work from the Depart- ment of Sricntitic and Industrial liesearch. This coni- mittee lavs tlo\vn the programme to be followed cot]- ncctrtl with d l cxperiiiicntal work. ~ n t l issues a report on thc tletluction i to be tlrawn therefroin.

- i n :innual rclmrt is issuet1 by the cominittee. copies of which arc regularly ol)tainetl I iy the Department of Main Roads from which details of the esperinicntal work are o1)tainal)le.

Experimental lengths of premixed maratlam with varving thiclinesier and iliffer-tit I)inders. resurfacing work usinfi different I)intlers, concrete pavement of varying thicknrs.sc~,. were inspected. from which I con- cludctl that finality with respect to the most economical designs for pavements is not yet mitliin sight.

Vol. 8, NO. I . _- 14 MAIN ROADS.

France. The French system of principal roads has been

nationalised, and these national roads are constructed and/or improved and maintained by a central road authority with headquarters in Paris. There are ap- proximately 50,000 miles of national roads. For the purpose of ;itlmiiiistratioii, the ronntry is divided into ninety L)q)artiiients with a Chief Engineer in charge of cach. For central control the I>epartincnts are grouped into twelve i n ntitiil)cr, with an Inspector in charge of caeh uiitler :in Lnspector-General who is responsible to the Director-(;eneral.

A tec1inic;il staff is attached t o the central oftice rvhich prepares standard drawings antl specifications for distribution to the “Ilepartments.” aiid to check up plans antl sl)ceificntions p r e p r e d and submitted hy tlic I>ep:~rttiicnts. Pr:ictically all design w-ork is carried out uiitler the d i r c 4 o n of tlie Chief lingineers in charge of thc Departments. \\‘here the proposed work is of some magnitude. reports arc first suhmitted to the Director-General and instructions are issued to the Chief Engineer ;is to the general character of tlie design.

\;el-y few new main roads are being constructed, hut practically the wliole length of the p , m o miles of national roatls has the pavement surface-treated and the alignment. grading and superelevation of curvcs are gradually being brought up to standard as funds pcrnmit.

F o r grades 5 per cent. is ain:ed a t on easy country, but 8 per cent. to IO per cent. is acccptcd in moun- tainous regions. Fo r curves on easy country 300 metres or 1,000 feet is the standard radius, but radii as low as 100 feet are sometimes accepted in tnountain- ous areas. Tlic niaximum superelevation on curves is I; per cent. The shoulders arc generally one metre wide and raised ahout 3 inches above thr surface of the road paveinent. Trees are usually planted along the edge of the shoultlcrs. and the two rows conse- quently are oiily about S metres apart on many of the road? where planting was first carried out. The mini- mum distance apart has since been fixed at I I metres or 36 feet.

..\ltogrthcr over 500.000 tons of tar aiid over 300,ooo tons of bitumen emulsions are used on the whole of French roads pcr annum. i.c.. on the national roads plus tlie roarls controlled by local authorities. The tars were not regarded as being of a high quality. but there has been iiiil~rovement in refining processes in late years ani1 consequent raising of the quality of tlic road tars. 14\’hile I did not see any of the “filled” tars being used. T was informed that tcsts carried out with tars filled with 40 per cait . of stone dust. or pre- ferably coal dust, greatly inci-eased the atlhcsivc qu;ili- tics of the tar antl helped VJ retain [lie oils. therehy lengthening the lifc of the tars considerably. I hacl the pleasure of inspecting r o d works in the country districts around the towns cf Marseilles and Lyons.

\I:ith the exception o f the pnvciiieiits of thc principal roads through the City of ;\Iarseillcs o r in tllc inlnlctli- atc vicinity. tlie p:ivenients consist of a waterhound pavemetit surfacc treated. ’h grcatcr part of these roads had simply the old wntcrl)ountl pavement ini- proved aiirl s t rm~thcncrl \VI) nwessnrp :tiid surface sprayed. \\’here widening anti new pa\wncnt were necessary. a good hatid-set bast was Ileing I:tid ;mtl a waterliounti wearing cottrsc laid thereon, in the linps of standard practicc. Sonic c i f :lie principal clirect roatls lwtwecn main centres 1i;ive a pavement width of 9 metres (30 feet) while otlicr national r~i:iiIs are 6 metres wide only or 20 feet. \Vlierc thew is a large volume of fast iiinviiig traffic. tlic width is slightly in- crcasccl. and in mountainous sections where the traffic is light, it may he retlticcd to 5 metres or 16 feet 6 inch es .

On the waterboutid pavcrncnt tar is yirayed and covered with screenings. ’This is rcpeatctl within twelve months. T’ractically all subsequent surfacing is carried out. using Bitumen emulsion as a hintlcr. Stir- facing generally confornis to the followin:: :--Tlic first surfacing of tar varies in quantity from r / , i to 1,/2 gnl- loti per square yard. depending upon the ccd i t ion of the water1,ound pavement and covered with screenings % to y; inch. The second coat is sprayed at tlie rate of 1/5 galloti scluarc yard and covered with screcnings % to ,% inch in size a t the rptc of T ton io thc 100 square yards. Rrsurfacing with emulsion liintler at the rate of I/S gallon per square yard and covering with screenings at the ratc of I ton to 100 scpiare y:irds is carried out during each of the two subsequent years, after which the surface is expected to last up to four or five years.

The following arc representative costs : Basic wagc, 25 F. - 30 F. per day--Ss. to 10s.

present rate of exchange? or 4s. to ,is. at par. Bitumen h o F. per ton apprm-f io present

rate of exchange, or $5 at par. I.lmulsioii Bitumen 4 jo E‘. per ton.-approx.

$7 10s. present rate of exchange, or F3 rjs . at par.

Ta r 450 F. pcr toil-approx. $7 LOS. present ratc of exchange. or L3 I

Ordinary crushed screenings- A t worlis.-zo F. per ton-approx. Cis. Sd. present rate of exchange, or 3s. q l . at par.

For selected scrcwiiiigs which are now insisted upon for most of the surfacing works, the emt niny be douhle those rates.

Transport.-.4 Franc per ton per kiluinct rc. or approx. Gtl. per ton mile a t present rate of exchange, or 3‘1. at par.

Petrol.-z Francs per litre, or appt-nx. 3s. per gall. at prcsent rate of exchange, or IS. 6tl. per gall. at par.

I

15 ~ __- November, 1936. MAIN ROADS.

MARSEILLES-NICE ROAD.

New Waterbound Macadam Pavement.

Tar Surfaced.

Concrete Roads. While thc total length of cement concrete roads is

gradually being increased in France, there has been no attempt a t constructing long continuous lengths. De- sign antl methods of construction arc more or less on their trial, but the following ronclusions can he drawn from reports made with respcct to the work acttially done :-

( I ) I t is ~ ~ ~ o r e economical to construct a concrete pavement in two layers, using the best avail- able local material for the bottom layer 4 in. to 6% in. thick, and selectcd liarcl aggregate for the top layer which should be laid simul- tmeously with the 1)ottom layer and be 2s in , to 3 in. thick.

( 2 ) Thorough compaction of the concrete by ramming or vibrating into position is essen- tial.

( 3 ) The proportion of cement to aggregate need not exceed 400 kilog. cement, 400 litres sand to I cuhic metre of stone, or approximately 1-2-4 for special surface or 1 - 2 4 for ordinary surfaces and the base course.

( 4 ) The aggregate used in the concrete for the top layer should be not larger than T % inches, and shou!d be both Iiard and tough.

( j ) Water should he kept low and should not excced 26 litres to TOO kilog. of cemcnt ( I gall. to 37 11). of cement uscd).

(6) An expansion joint the depth of the wearing course ( P in. to 3 in.) only is required. This should he ahout :4 inch widc at 40 to j o feet intervals and filled with a plastic material the colour of concrcte.

(7) It is essential that special precautions Le taken t o leave the surface rough so that vehicles will have no tendency to skid.

Tar. 111 France, tal is largely used for tlie initial suriac-

ing of waterbound roads. In order to improve its quality, rock asphalte. I)itunlcn. coal tlust, or other mineral or org;inic matter have been added. No iti- formation is available as to which mixture is likely to prove the hest, The use of tar-bitumen compound is growing rapidly, the Iiitumeti content usually being 20 per cent. or under. I’ulverised coal is used as a tar filler and it has becn found that 50 per cent. can be incorporated and the mixture readily spread. Lime- stone tlust antl other fillers arc also used. Experiments would indicate that such mixturcs are likely to give good results. There is a tendency to use more viscous tars than formerly with a view to increasing the rate of setting.

Bitumen. For surface work the tendency is toward the greater

use of a “Fluid” (Liquid) Bitumen. This can he sprayed a t ;L much lowcr temperature and as setting is slower it holcls ;i bigger proportion of the cover material.

Emulsions. Sonic tar and pitch emulsions h a w been prepared,

hut their use caii only be regarded as experimental so far. Bitumen emulsions are prepared either in a pa(ltllc mixer or by passing the materials (hi-ough ;i colloid mill. It is claimed that the latter prucess ensures a product with cot?stant characteristics as to its ability to withstand the tendency to co:cgulate after ;i period of titile and to the ratc of “breaking” which canncrt be effectively controllet1 i n the former p r o w s . Nincty per ccnt. of the eniulsion u s d i n France is nianufac- tured in a colloitl mill. The viscosity is controllctl I)? the atlditioii of chemical cotiipoumls. ’l‘hr details of the manufncturit~g- processes x i d the emulsifying age’nts and chemical coinpimnds use(l are licpt secret by the manufacturers.

16 MAIN ROADS. -

Vol. 8. No. 1

From tests carried out it h:is been found that the rate of breaking of ail emulsion is in inverse proportion to tlie rrsit1u:il wi ter contcnt iininet1i;itely the Irrealiing cominences. Rapid hrcaki i r~ emtilsion will set contaiii- ing 1.; to 25 per ce'nt. of witer tloating in the I)itunicn, whcreas a nictlium 1)rcakiiig r!iiukion will contain only 8 to 10 per cent. of water and ;I stahle emulsion j to S per cent. Experiments have Iweri carried out mitli an emulsio'n containing a hller. S o tlrfinitc inforination can yet lie tlctlucctl as to what ;~tlvantagcs. if a y . can lie secured thercby.

Cover Material. The cover material is sclcctetl with great cart. ;nit1

tlie tendency is to iise larger sizes than hitherto. X mixture of broken stone troin ,; millimetrcs to 2.; milli- metres ( A / 16 iiicll-i/S inch) lreiiig conitiion. \\.liere 01)- tainahle light-coloured materials are given preferciicc in order to rcducc somewhat the hlacli colour o f tar or I)itumen. Every endeavour Iias hccn iii;itle to incor- porate the nxcxinium nmounit iiito tiny given quantity o f spr;iyed binder.

Macadam Roads. Selccted slag is very oltcn irsctl for tlic prelnrntioii

of a premixed tar iii~ic:id:ini road: tlie tar and the slag as a rcilc bein: the pmlricts of the sanic district. In other districts n nicclinm I)rcaliinp I)itunien eniulsioti is largely used as the Ijindct- \\-it11 suita1)le local stone. the eniulsioh amounting to io :)er cent. i n volume of tlie

aggregate. . \ p i l i cmulsinns :ire preferred for a pene- t ra t ion or semi-penetr:ition mac;itlani p;~vi~111ent. Cur- rent practice is for the I:ltt-r to l~ atlopte~l. using 3-4 litres of binder per .square mctrc with :L scxl coat oi T T/? litres, i . r . , ;~~rproxini:itely I / L g::tllon to L / J g;illoll per sqnare yard with ii seal coai of )< g:ilIoll ]>er qviarc Fird.

Plant. (;eiic~i-;illy the units of ro;d l)I:int i n m c O I I 1~rc11cli

i-o:itls ;II-C of ncll-kno\vn t?y>cs. I Tnwerer. there arc two units of pl;int to wliich I wish to direct specific attention.

l'lic lirst of these is a ~rnrtalilc I~itunicn eiiiulsiow ~)ro[lucing plant. These \\ e lint into nsc ii i ljrancc a'iitl sonic were exlroi-tctl. lrut ,so f a r :is l7r:ini-e itsrlf is concernctl. their iisc hi Iiseii :~l):intlonetl. as fixed plntits Iiavc I)ceii crectctl. :iiitl c ~ i i ~ ~ l s i ~ i ~ i s :ire 111r\v :iv:iil- alrlc at reasonable cost in c-oiii~rai~iwii with the cost of IJitunien. without iintluc tr;uiq)ort ljcing incut-I-ctl. 'Ilic pl;int is of a type suitable for IISC i i i t l i c cuutitry districts of Australia.

The second unit of plant xfcrrctl to and insliectecl at tlie xvorlis \\.a.< nicchai cal sprayiiig iii;icliine fitted with :i ceiitrifu:;il lirojc or. It essenti:illy co'ii- sists of :I gravity Irintlei- feed 1 e to a conical projector drivcn lip a vertic:il s1i:ift :it I ,400 r.p.m.. \vliich pro- iects the m;itei-i:il on t o (lie ~:i:i(l. The tliamctcr :ind le t i~t l i of the conical 1)roicvtcrr is varied to suit the \vi(ltli of spray tlesirctl. Tlre stantlard sizvs are for :i 2 metre. -.T< metre. :inti 3 iiictre width of spray.

The Permeability of Pavements. Interim Report on Tests.

As tlie majority of road pavement f:iilures can be attributed to water, one nl tlie generally accepted prin- ciples of roatlmaliir~g is that a surfaced pavement should he so constructcd that it prevents surface water passing through to the foundation or subbase. :incl tiic usual practice adopted to obtain and m:iintaiti this condition is to sral pav~nicnts :it more o r less regul:~r periods.

Open-textured premixed macatlam (u~isealctl) ! i w , however. been tisell auccessfully in surface courses, hut in the majority of these cases the premixed material has heeii placed 011 an impcrvious surface which "sheds" any water passing through the pre- mised material antl so protects the foundation :itid s d - base. Sometitiies the original surface may not, Ire cntirely iniprrviws. Init the heat of the I)remirctl m:cterial softens tlic binder in the surface t u be cove r~d antl causes it to flow into the minute crack.: antl oy11- ings ancl so completes the "sealing" of the surface.

To determine ivlictlrer a scirfxe is impcrvious. and i f not so, the rate at, which water 1) surface. has been tlie subject of some prcliminary rc- search work done by the Department during the past

fen, months. The types o l apparatns used, which :ire u i a very simple natiire. are slinnii in tlic :~tt:tclictl illu:tr:itioi~ m i page I 7. antl 1)ricf ilescriptionx :irv givcii hclo\V.

.'\I1 tehts arc carrictl orit 0 1 1 tlry p;tvenietit ,urf:ws. and the area to lw tested must I)(, tliorouglily clcan and the d u t rcniovrtl from ci-;~-ks. r ~ c . I n iirtlcr t n coni- p r c results olrtaine(l with ilic differclit types of apl)aratus. reatlings x r convcrtctl to vrrluiiic ])er square foot of Iwvcnient for ;I ten-minu~c interval. 7'ypc ( ( 1 ) coiiiists of t\vo rings of galvaiiisecl i r w , the

initcr ring l~cing 1.7 inches diameter ani1 I iircli high. ant1 tlic iniiei- riiig I 2 i n c h rli:imeter a 1 y l

4 i t i c h r h liigli. 'Hie two 1-ings arc pl;icPtl 011 tlic surface to be trstcd ailcl ii watcrtiglit x ~ i l lwt\vccn the surf:ice aurl tlie inner ring olitaitictl I)? pour- ing hot parailin o r similar su11st:iiice 1,ctn.rcii thc t\vo rings. 'l'he iiiiicr rinK is thcii t~ille~l \\it11 water. :ind :I fter a prctleterminc(l I)ci-intl. usu:i l l~ ten minute:. the quantity n f water. i f a n thrrrugli the surfacc o f the Inrciiicwi i. a by niea~ui-ing the c1ii:intity ~ r c c ~ ~ i i r c ~ l t o till tlic ring to tlic level of the water first placed in it.

November, 1936. MAIN ROADS. 17

7ypc (b).-This type is made from %-inch mild steel plate antl, as can be seen from thc illustration. tlie seal with thc road is made by the use of a ring of sponge ruliber L iuchrs thick placed under the flange of the apparatus, which is forced down on to tlie road by means of a11 ordinary car jack push- ing against soiiic portion of a motor vehicle. The pressure so imposed compresses thc rubber ring on the surface providing the necessary seal to pre- vent the water placed in the ring from Icakiiig away ovcr the surface of the pavement. The measurement of the quantity of water passirig through the pavcment is ascertained in the same way as for type (a)-the effectivc arca of this type has a diameter of 7% inches and has a height of approximately 4% iuchcs.

Typc (cj.-This type consists of a graduated glass cylinder (open both ends), approximately 4% inches high atid 3 inches diameter. The seal with the pavement is obtained by the me of putty forccd on to the surface. To ensure a constant effective interiial area a ring of metal about U,

Paraffin or beeswax filler

\

/

1

\

inch high and 2% inches diameter is placed on the pavemcnt' inside the cylinder to prevent the spreading of the putty over the area to be tested, and in this manner a coustant area is maintained for all tests. The quantity of water passing through the pavcnient surface can be read direct. Colouring of the water facilities the reading of the water levels. This type of apparatus is far more convenient to use than either of the other two types referred to, and furthermore, readings may Ire obtained at any time during the period of the test, and in this way the rate of flow ascer- tained.

A considerable number of tests have been made on various classes of pavement surfaces (mainly on S.H. No. 5-Great Western Highway). antl from the information obtaiued it is con- sidered that in the case of the ordinary hitunien sprayed surfaces the results give a true indication of tlie pcrmeability of the pavement. With opeii-textured surfaces, such as is often the case with road-mixed and plant-mixed macadam courses, the results obtained are

~ o o s e t imber support for Liftingjack t o liftcng j a c k . bear against

, , I /

TYPE A

Graduated measuring glass ( a b o u t 4 i high)

15" ------/ I ,

R u b b e r g (sponge)

T Y P E t TYPE ' 0

18 MAIN ROADS. Vol. 8, No. I . --__ not always a true indication of the quantity of water finding its way to the foundation antl sub-base. as water may pass through the new surface course to the original pavement, which. if impervioas, prevents it from passing through to the foundation. The water then flows through the surface coursc, eveiitually find- ing its way to the road shoulders along the impervious surface of the earlier pavement. In order to ascertain the true coirtlition in regard to the water-proofing of the fouridation it is necessary to remove a small area of the surface conrse and test the original or earlier ]iavcnient.

The porosity of the surface course may be gauged by isolating an area in siich a manner as to allow the apparatus to make contact with the original surface and prevent the escape of the water. I t will be neces- sary, of coursc. for the original surface to he irnpervi-

Tcsts were taken over a considerable length of the tireat Western Highway at intervals of r/Ioth of a mile, two tests in each case; one 2 feet from the edge of the pavement over the wheel tracks. and the other 5 feet from the edge (hetween whccl tracks). The pavement, width is IS feet to 20 feet. In the majority of instanccs there was a marked tliffcrence in the results obtained frtrm tests taken at these two points in the cases uf premixed antl road-mixed surface courses. A far greater quantity of water passed through the pavement at tlie point 5 feet from the edge than at 2 feet from the edge. It is thought that the "kneading" action of the wheels of tlie vehicles on the mixed material during the initial stages assist in mak- ing the surface less pernieaLle, whereas tlic oil drip- pings from cars over a narrow width. the centre of which is approximately .; feet from the edge, have an injurious effect on the binder on the surface and so destroy the film which may assist in water-proofing the snrface.

Tn the niethod adopted by the Department in road- mixed seal work thc hinder, in form of a cut-hack bitumen. is applied in two sprays; the first one is applicd to the existing pavement surface a t a rate which it is considered will completely seal the surface, the aggregatc is then spread on the sprayed surface and the second application of binder sprayed over the spread aggregate at il rate sufficient to complete the mixing of the aggregate. In this work the apparatus can bc used to determine whether the first application has sealed the road. and also the rate of increase in the density of the mixtiire of the binder and aggregate in thc finished course. I n t,liis connection tests made on road-mixed seal work laid early in March this year havc indicated that, during the first week after completion, the mixed aggregate was so porous that tlie water used in the test bubbled up to the surface round the outside of the apparatus in a circle of a diameter of about 30 inches (the outside diameter of the apparatus is about 12 inches). Tests taken at one month and three months after completion show that the new surface uiidcr the action of traffic gradu- ally becomes closed.

ous.

Had the treatment heen carrtetl out during the carly part of the summer the action of traffic would, it is thought, have accelerated the "kneading" of the wr - face.

The following results, which are the average taken from a number of tcsts, indicate the increase in density due to the consolidation and kneading action of trafic :-

I n a ninnlrcr o f cascs where cracks in the pavenient surface indicated the presence of water i n the fouiida- tion. tlie tests taken over thr cracks gave negative results. whereas in other cases positive rcsults were obtained on scctions of the pavement where there were no cracks or openings perceptible to the naked eye. Water was not apparent on the surface over the cracked areas, but in a nuniher of cases where the road was opened up the fountlation was found to bc tlatnp. Over the erackcrl arcas the time of test was extended to twenty miniit,es.

The following hypotheses are suggested as likcly explanations nf thc negative results ol)tainr.,l over the cracked areas :-

( n j The water may be finding its way to the foundation from an undcrg;onntl source at a pressure at least equal to the pressure due to the head of water in thc apparatus.

( b j The foundation at the time o f the test may have been saturated with water which pre- vented any further quantity, measurable with this apparatus, entering the pavement in twenty minutes.

( c ) The resistance to flow clue to snrfxce tension in the cracks or openings beneath the surface cracks may bc greater than the pressnre due to the head of watcr. (If this hypothesis is correct. it may appear anomalous that water should pass through pavements where no cracks or openings are perceptible, since it is known that the smaller the opening or crack the greater the resistancc due to surface ten- sion per unit area).

(U!) As failures in pavcmciits are frequently due to change in volume of the foundation such as occurs with clay, the wetting rlf tlie clay sub-base causcs an expansion with iubseqiient cracking of the pavement, antl tlie clay

November, 1936. MAIN ROADS. 19

"works up" into the cracks in the pavement and so prevents the admission of water froin the surface.

It will be seen that the tests carried out have only brought the investigation to a stage at which certain hypothetical explanations can be suggested. It is in- tentletl to continue these tests in the hope of arriving

at some definite conclusions as to the conditions which affect the permeability of hituminous pavements, and any further results obtained will be puhlished at a later date. The foregoing description of t.he work clone and the tentative results thereof are pu1)lislied with the object of ~uggesting the possible lines of attack on the problem. -

Australian Road Statistics. Compiled by direction of the Annual Conference of State Road Aurhorities

1. Lengths of Roads. There arc about 500,030 miles of road in Australia,

but this inclntles anything from asphaltic concrete or wood block city streets to ill-defined routes in the out- back which are known almost wholly as lines on official maps. Inforn1ation is not available as to the stage of improvement reached in the roads of the six States of the Coninionwealth. but froin the distribu- tion of population it is evident that thc great hulk of t,lieni are traffic-made tracks. or of earth or light gravel construction. Thc length of roads to be found in each State varies according to the popiilatio'n anrl area. the fornier being the predoniinating factor. The actual position is disclosed in Tahle I 1)clow:-

LE I.

I n \Vestern .\ustralia. for example. there is less than half a million ~)eople. but it is by far the largest State in area. ani1 as ;I consequence it requires 74.000 miles of roatl. or I 5 per cent. of the total mileage. to serve 6 per cent. o f tlir population. The number of motor vehicle.; varies fxirly regularly according to the population. although their use is somewhat greater in South :\List ralia ant1 \\'ester11 Australia as compared

with the remaining States. The heeds of the road system in each State rnay be judged by the relation of population and vehicles to the roatl mileage. From this it is seen that vcry wide variations occur. In Kew South \\'ales, for instance. there are twenty-two persons and 2 .2 motor vehicles to be catered for : and. incidentally to contribute to each n d c ; whereas in Queensland there are nine persons and less than one motor vehicle. It is evident that the degree of im- provemcnt will be greatest where these figures are highest since they measure the extent to which each State can afford to devote money to roads. i t was in an endeavour to take account of these factors that the Commonwealth (;overnment decidctl. in 1923. to dis- tribute iiioney to tlie States for roads on a population and area Ixisis. The money granted was intended ~~riniar i ly for developmental 1mrposcs anrl \vas appor- tioned so that three-fifths W J L I ~ ~ be divided according tn the population o f ex11 State and t\vo-fifths according to area. 71'he same I)rinciple has been incorl~orated ill the current scheine under which the Comnion\vealth (;overnment pays the States the proceeds of z,\4tl. per gallon on petrol inlportetl into tlie country ancl I !Ad. per gallon on that refinerl locally. This hasis will be continued. it is understood. when the agreement is coinpletetl for ten years from 1st July. 7937. increasing the Commonwealth (;overnment's contri1)ution to 3'1. l>er gallon and a l . per gallon. respectively.

In the aggregate each mile of road in Australia serves thirteen people, and is required to acconiniotlate an ayerage of one ant1 one-half vehicles (running about 6.700 miles per annum per vehicle). The rate of improvement will therefore depend Ilpon the amount this number is able to contribute hy direct taxation, as the owners of land adjoining the roads. or as motor vehicle operators.

2. Road Claaification. The bulk of the populated area of A\ustralia is authority has been set up as a R o a d or Commission

divided into local g-ovcrning units. known by various or State lkpartment to concentrate on the provision hanies, e.g., Municipalities and Shires, each body of a roatl system suitable to the new- type of traffic. usually administering an urban or rural district. These It has been accepted generally that motor vehicle users bodies are primarily responsible for the upkeep of all should contribute to roads and that the money SO

roads within their boundaries. Iluring the past twenty derived should be expe'nded primarily on the more inl- years, however, the extraordinary growth in the use portant routes which lead from one State to another of motor vehicles has made some reorganisation of re- or serve as links hetween the centres of population spo'nsibility necessary, and in each State a central within each State. It has thus been necessary to

zr,4ro 6,367 8,715 6,777 3 ,231 . . .

select the roads to be controlled or assisted by the central authority and these have been known as main roads. More recently, too, thc most important of the main roads have been rcgartled in several States, as calling for a greater nieasure of attention and assist- ance than they conltl receive i f allowed to remain on the same footing as ordinary main roads. and they have heen classed as State Highways. .I further class of road fouiicl in m:my States is the developmental road whicli is tlesignc~l to open up new areas for settlement or to carry thc produce of settled districts to the nearest railhcatl. Each State has proceeded inde- pendently i n determining the road classification to be atloptctl antl the extent of each class. I t will he i ' i i-

tcrestirig tlicrcfore to compare the current classifit,;)- tion :rntl to see the rclationsliip bctween classified and other roads. 'This information is included i n Table I1 hereunder :-

TABLE 11.

20 !VIAIN ROADS. Vol. 8. No. I . ~~~~~ - ~~ -~

I

3. Sources of Funds for Road Upkeep.

In the three eastern Statcs it will be seen t h e is a State Highway system which comprises about one- third of the total length of all main roads, and in Tas- mania, where the total length of road is coinparatively small. it has not been found necessary to (listinguisli hetivccn State Highways and other niain roads. There is in New South \k7ales an intermctliatc ty 'e of road known as trunk roads (included in "Other Main Roads" in the table) which h;ivc a total length of 2.435 miles. Thc rate of assistance for \vork suli- sitlisetl by the central authority on thesc ro:ids is greater than for the ordinary niain road.

Tllc proportion of classified roads is very consisteiit and would indicate that a , systrtn which provides for the classification of allout IO per cent. of the total road mileage usually meets the requirements of a trunk system. This is also the experience in other countries. There is not available information to show thc tlistrihu- tion of traffic according to road classiticatioiis in AUS- tralia. but during recent years highway financial sur- veys have hccn undcrtakcn in several States in the United States. a'nd this aspect has I)eeii covered. These surveys have lieen unrlertalien for the guitl:ince of the United States Bureau of Puhlic Roads. and from the information gathered i l l rcspect o f \\.iscon- sin. Illinois. Michigan. Minnesota ant1 New 1 [ampshire. it is concluded that the trimk road syetcrn carries from 40 per cent. to 60 per cent. of total traffic. de- pending upon the density o i popiilation antl location of the larger centres in each State. I t is likel!. therefore that the main roads of Australia. having a total Icngtli of 46,000 miles. carry about one-half the tntal of all traffic.

To meet the cost of works required on unclassified roads, it is usual for rates to be levied by local authori- ties on the value of land within their areas. The local authorities are also required. however. to make some contribution to the cost of classified roads. 'I'his may take the form of a direct contrihntion towards works carried out by the local authority or may represent a payment to tlie central authority according to the value of land i n each area or according to the length antl work required on the classified roads within the area. The principal fil'nds of the central authorities. how- ever, are derived hy taxation of motor vehicles or fuel. The taxation of vehicles is a State function and the methods of assessing taxcs vary in the diffcre'nt States. In some caws a flat rate registration iec is paid and tax imposed in addition. In all cascs. however. the tax varies according to the weight of vehicles in each class, i .c.. cars, lorries, omnibuses, etc.. or by some combination of weight horse-power and carrying capacity. The taxation of fuel conics within the juris- diction of the Commonn.ealth Govermncnt. which ;It present collects a duty of 7d. ~ i c r gallon (excluding primage) on pctrol imported and .;%d. per gallon o ~ ! that locally refined. Of these tlutics z z d . ant1 I % I I . per gallon rcspectively are regarded as charges for road maintenance xiid improvement and are transferred

to the States on the popnlation and area Ilasis pre- viously described.

Rctween 1920 and 1930 fairly subst;uiti;il contribu- tions to roads were provitletl from general Statc re- veiiucs. These were made in two w:iys---partly by grants from revenue and partly by the raising of loans for roads and requiring interest and other chargcs to he met from revenue. From ;il)out 19"o. however, there was a general tendency to review the funds set aside for roads and to restrict reyenue grants for t h a t purpose. 'There was :ilso ;I gencral niove to require loan charges on road loans to I)e met from tlict taxes paid to road finitls. antl this is no\v tlic practice gener- ally accepted. There has I~ern a gratlwll retlnction of loan cxpe'ntliture 011 classilietl roads Iiecaucct several States have rcaclietl the stage whcre tlic niost impor- t a n t routes are i u reasonalilr ni-rlcr ancl tlie :inthoritir; deem it sufficient to pcrinit tlie ratc of further iml)rove- men to lic conti-olletl Iiy tlie funrls ;iv:Iilalilc frrrm revenue. 1.oaii money i c still h c i ~ ~ g used i n special

er. ; i i i d li;~i-tic~iIarly for work, tlcsignctl to I-elicrc i~neii~~~loyiiicnt. I'hc cstriit o f the 1o:in: (levotctl t o clashilicrl n i ; i d t,,g:c.ilier \\.it11 <lct:iils of tlie reiii;~ining .SIJIIrCCS of ci ,~i ip, :ire ~ilio1v11 it1 '1':iI)le 111. \\-hicl1 gives thc averagc, aii1111a1 figul-c. inr the five years to 30th June, 1935.

21 -

November, 1936. MAIN ROADS. ___ T-4BLE 111.

Victoria. western Anst,ralia.

Percentage Total. to Grand

Total.

f r,121,.j08

335.814

60,972 351.832

...

48.1X2

f l<eveniie-

Vehicle taxation . . . . . . . . . . . . r,300.607

270 . . . . . . . . . . . . Pctrol taxation 555.430

l'arliamcnlary votes . . . . . . . . . . . . I-ncmployment Rclicf Grants . . . . . . 25,205 ('ontributions by T.ocal huthoritici . . . %14,853 ~Iiscdlanrori.: . . . . . . . . . . . . . . _ i 49,061

t. i4

895.933 239.634 498.490 140.643

...

1,927,308 30,000

1,507,264 638,093 250,000 ...

Sub-total . . . . . . . . . 2,225,426 ... ...

Total . . . . . . . . . . . . . . .

1,oans- Statc loan? rcpiryablc froni road funds ... 46,oro State loans not repayable from road fnnds Irnemploynmt ltclief Grants from loans ...

Total . . . . . . . . . . . . . . . I 173,513

... 127.503

~~ . -

Total inconic from all sonrces . . . . . . i 2,358,939

353,670 j ... 4,900 ~ . .

...

35'::5 70 186, I 7 I

2,083,479 7,623,162 1 100.00

( 0 ) These transfers werc not madc cvery ycar. Io New South Cz50,mo bas been traniferred for threc years from rg3z/g3 , the Imn

Wales & ~ D O , M O was transferred in 1931133 and in Victoria &rso,om in liability of the central autbarity being correspondingly reduced.

I O Queenslaad

It is to bc explained that the amount shown for South Australia as a .Parliamentary appropriation is virtually motor vehicle taxation since the greater part of that tasatiiin is paid into Consolidated Revenue and

ai1 amount then voted for roads. In the total it will be observed 89 per cent. of the money is provided from revenue, and most of this revenue is found from motor vehicle or fuel taxation.

4. Expenditure on Roads. The esperiditure oti roads by the central authorities penditure on other public works, and it is therefore

can he secured readily because their accounts do not possible only to estimate the approximate aggregate contain cspcnditure under other headings. The Gnan- cxpenditure on roads. In Tahlc TV there is set out cia1 statements of local authorities, however, fre- the total expenditure on all roads in Australia as qucntly do n8,t st-parate road expenditure froin ex- nearly as it can be securcd for tlw year 1934-35 :-

-~

TaS-"l.i

-

2 I I ,648 42.86 30.356 6.15

242,004

~

I I I l kpendi turc un Classified Roads ~

.\lain Roads . . . . . . . . . I'ercentagcof total . . . . . . Develnpmental Roads . . . . . . Pcrccutaxc of total . . . . . .

Total Classified Roads ... Percentage of total ..

44'447 36.28

169,491 13-93

...

. . .

. . .

...

. . .

. . .

...

...

...

. . .

...

...

...

... -

610,738

50'21 59'49

Expenditure on Unclassified Roads- From Government funds . _ . From funds of local authorities Percentage of total . . . . . .

Total of unclassified roads ... Percentage of total ...

Perceotagc 01 total . . . . . .

Grand Total Expenditure

Percentage . . . . . . __ .

1,275.875 8.58

48749,519 31'93

161,109

90.668 18.36

25 1.777

32.63

~ _ _ 605.693

49'79

r.216.431

50'99

493,781 d / 4,867,245 42052,703 3,7453253

...I 100'0 1 100'0 I 100'0 100'0 1oo.o

22 MAIN ROADS. Vol. 8, No. I

~~ l h e table relates t o one year only, antl in some States niay not accurately represent the general posi- tion, for example in New South \\'ales, it sitbstantial amount was exl)ended during the year from ( ;overti- inent iuntis on emergency relief works. It will lie seen. however. tha t it is usual for at least half the total exl)cncliture to I)c m:itle on the classitic(l roads. although these total only I 2 per cent. of the Icngths of all roads.

and all roads than the remaining States. The com- paratively low rate of expenditure per vehicle in South Australia will also be noted. For the Commonwealth as a whole it will he seen that roads cost f 2 4s. per head (which corresponds to ahout f8r per mile of road) or a t the rate of approximately S s . pcr neck for each of the 7 0 0 . m vehicles u4ng theln.

T..\BLE V.

In tlie aKgrepite the cost of State Highways and F.xpenditore on rlas,ihcd n m t l ~ . ___ State.

Main Roads rwis into j z per cent. nf all costs antl for convenient :idministration the bulk of this cost is paid by motor vehicle users. I t was slinwi i i i an earlier table that the persons antl vehicles for each mile o f

Per Pcrson.

road varies according to the popdation antl area of each State. Tt will tliercforc be interesting to sec what variation takes place i i i the expentlitnrc pei- prrson ;wtl per vcliicle both on the cl;issifietl i-oad system antl on all ro:ttls. "I'a1)Ic 1. .;lii)\vs this inforniatio'ii. the cxpcii- diturc for cl:issifietl ro:ttls rcprescntin:: the ;iver;lge annual exlrenditnrc lor tlie five years to p t l i jutic. 1985. and tliq expentlitiire for all roads rrpresenting 7984-35 only.

I t wonltl I)c c s p e c t d that the espentliture per head woultl (1ecre:tsc as thc population incrc:iscs. I)ut i t \vould sccin t1i:it the popitlatioil in any State is tiot sufficient for this pmsition ttr arise. I<clatively. Queells- land spends tiinre on roads lroth for classified road3

S e w South Wales . . .

Victoria . _ . . . .

(jueensland ... . . .

South Australia

\Vcstern Australia . . .

Tasmania . ._ . . . I

. . . ~

'Total . . . . . I

5. The Cost of Roads compared with the Cost of Road Transport. _ . 1 he expenditure on roads set out previously really

represents a part of the cost of rontl transport. I t Iias been tlcmonstratetl on many occasions that ini- provement in roatl locatioiis ant1 surfaces Iring with tliem rcrlurtions in the costs of vcliicle o1)rr:ttion which are fa r greater thaii tlic cost of the improved roads. In order to sec therefore what firlrl tliere is to re- arrange the various items o f cost which go to malic up the road transport bill. i t will I)c of v:iluc to conip;ire tlic expenditure on roatls it1 each State with the q - proximate cost of road transport. This latter cost caw 'iiot he ol)t;iincil ;tccurately. Iiut a fairly 1-elialrk esti- mate can be m:ttle ironi petrol coiisiin1l)tion return. ;mil known operatitig costs. For the purpose of tlic estimate tlic "average" vehicle has Iwcii take11 to use IS milcs 11er rallon antl t o c o h t h l . i)er mile to run.

in road expenditure \vrrultl Irring ;tbuut it retlurtioii iii the total aiinual cost of L i ~~.uoo.ooo. I t is to I)c re- nirnilwetl. Iiowever. that p o ( l roads un(loulltc.tlly i n - crease travel. ant1 it i; thcreforc ~)rol)aIrlv that ;LS t l iv roads continue to iinl;i-ovc tlir tot;tl outl;iy ~ I I roxl transpoi-t will grot\- I)ecause of tlic registr:ttioii o f neiv vcliirles :tnd the greater nsc of thow iiow wgihtcrc(I.

I.IHIX vr

I I . . . The cost r)er milc ironld inclu[le the cost of road.: and I

.~ . __ operating lahoiir ( lor rommcrcial vehicles) as well as

a t i d so oil. On this hasis Table VI shows the iiiform;i- New South 138,912 6 ,557 r .566

tion for tlic Coiiiiiir~n~realtli ;intl constituent States.

the running cost for depreciation. fuel. tyres. repair>, millioiii,

\Vale:.

29 _~___ November. 1936. MAIN ROAbs.

Vol. 8, No. 1 . _-__ 24 MAIN ROADS. __.

Design of Concrete Slabs for Bridges. Methods Adopted by the Department of Main Roads.

Foreword. Let a = Ir~irgth of shortrr side< of pdllcl. b - , , 1oiigc.r , , p = total load p'r unit ai-ca. q = h a c i per unit ;irw carricd tq . s t r i p Iui-:illcl to

Y - load per unit area carried b!. htrips p m l I t , l to

Then consitlering t h r t lct lrctioi~ c i i thc cimtri: strips :

I N the May, 1936. issue 01 "Main Koads" an article was published setting out the methods adopted by thc lkpwtnient of Main Roads in the design of most of the usual cases of concrete slabs for steel or concrete Iiritlges. l'he present article deals with the detailed design of sqnarc continuous slabs to which refcrciice was macle in paragraph 3 ( c ) , page 101, of the IMay 1936 issue.

sides a.

sides b.

Approximately Square Continuous Slabs. ' I _ - - h4 Y a4 -

l'a'nels supported on girders in two directions. forni- ],ut y 1 / ' p

I he only cases where such panels are used i n bridge

ing approsiniatrly square panels. are designetl in t1i;s Department Iiy the methotl of H. Marcus.

work are in long concrete pirder spans (whcre the a

$ = f ' - - (4' -+ b'

I . U 4 and r = p - 4 , *?

spacing of m:iin girders is in& as large as 'practicable to reduce the number of the big main girrlcrs, and

make approxi- inately square deck pancls) a'nd certain forms of Roor- iiig for steel bridges zq

These loads (I and r i f applictl to the separate sets of

girclers are provi,jed at intervals strips cause moments per unit \ \ d t h of slal) of

K = - 9 f l z ;it ct,ntrc of strips psralld to sides < I .

'The case of a sleel I)ritlgc is very rare and need not be considered in this article. Nearly all concretc 1)ritlges of this type are of tlic standard width of 20 feet between kerhs supported by two girclcrs; in this case consideration of the niaxinium cantilever portion of slab outside the main girders limits the spacing of the main girders to a niinitnuni of 15 feet 6 inches and particular attention will be given to the design of approsimatcly square slabs having a side of 1 5 feet 6 inclics transverse to the traftic.

' l o avoid serious complications to forinwork and reinforcctnci~t all intermediate girders should be placed square to the main girders. If a skew structure is essential tlirn it is necessary to provide trapezoidal end panels sl~ecially reinforced.

C;ilculations of relative stiffness show that tlic tor- sional deflections of the main girdcrs between cross girders are negligible and that the dab beliaves as though fixed at the niain girders. 'Tlie slab is con- tinuous ovcr the intermediate cross girders and although t,hesc cross girders arc not su rigid as the main girder.: thc continuity of the slal) and the rigidity n l tlic cross girders is sulficirllt t o adequately fix he slab. The end cross girders arc su1)jecled to heavy torsion stresses and will he of sufticieiit rigidity to fix the slab. The slab panels rimy therefore l)c considcred as fixed at all silpports.

Uviforiia Lond 011 Wliolr Paitel Fi.red all .Tides (Dcnd L o o d ) .

'fliese moinrnts liavc iiow to I)e correcietl for the slicar forces bet-ween successivr strips tluc t o the fact that these strips arc not inrlcprntlent but f o r i n part u f ;L continuous slab. Rlarcus slimvs that the correction t u the positive moments can lic made by tlic use of a corrccting factor 1- given by the formula :--

( ' fhc value of \ ' \rill be tlitfcrciit for the tiro tlirec- tions of moment if t l ~ r con(1itioiis of support at the pair of sitlci o is ~lillcrent to that at the sides b xiid the :tliove wlue only applies for slabs fixcil at all edges. ;)

I . I he aetnxl masiiiiuin j~isitive moments are:---

hfn =, VE;. ~

at centrc of strips parallel to 24 sides n.

, . I he negative moments ;ire given by the forinnlae :-

311 ~~

P - a' __ b4 at supports of strips p a r a ~ ~ ~ ~ to sides U . 12 n4 f h4

p 2 Mi = - - 24

Let the slali (see Fig. 7) be divided into two series of strips, one parallel to each pair of sides.

November, 1936. 25 MAIN ROADS. ~

FIG, 7

FIG.8

I l o5 I / I /s I t

Rufm ; I b p P sq f f ,p .- shoder side ,n ff

FIG. 9. DEAD LOAD MOMENTS

The foregoing moments are the moments on the centre portions and will fall to zero for the edge strips. The general form nf the iiioment tlistril)ution that is usually assumed for tlesigii purlirises is shown on Fig 8.

Values of M,, M,,, M:, Mt, and V are shown in fig. 9. The moments are givcn in Ib. ins. per foot width of slab for a loadi, of I Ih. pcr sq. f t .

(oiirc.ii/rcitcd Loird.v 011 .Si.rb l;i.r(vf ot 011 Sides 1 Lire L o o d ) .

l'lie iiiaxiiiiiini stress io r tlir standard loading will usrially occur \\.it11 a single wheel or with two wheels mi tlir dah 1mid For the normal case of a z girder -10 feet roadway the \vui->t coiitlihti will be two vehicles passing; the two inside wheels will be at 4 feet centres while the outside wheels will be over the main girders.

26 MAIN ROADS. Vol. 8, No. 1 .

Three cases of load havc therefore to be investi- Let Ma, hTb, Mi, Mt, and V liavc the same significance gated :- as for uniform loads. Marcus shows that the total

( i ) Single concentrated load (see Fig. IO).

(ii) T I ~ O loads. axis of loads parallel to shorter

(,iii) Two loads, axis of loads parallel to loiiger

moments may be taken as- Case (i) (single load)-

8 3 n I M, = v. - . (Q + - . I<)

>I,! I = v.- . (I? 4- - . -

Mi = - 0.

h r a J J J 8 ‘ ’_

sides ‘‘a” (see Fig. T T ) .

sidcs “b” (see Fig. 12) . 8 ~ h . 0 )

I I I c w h caw let :- I’ 1 total load on ~ ; L I ) .

b M:, = ~ - I<. I< = , , I 1 1). J 8 ’ 2 = total load carried by strips p;tr;ill~~l to sitlcs U .

p ~ ~ ~ ~ ~ ~ , ~ has investigatecl the actu;ll values of Q allti R. The forniulae for their exact evaluation are very complex. but lie shows that very sniall errors result I)y assuming the yqn-oximate relation for case ( i ) :-

Case (ii) (Two loads axis of 1o;ids parallrl to sitlc.; U -

\I:, = v. - 0 +I- - (I ~ 4p)p i --(lk + 4k2 J ;I{ h ( I - k )

M,, = v . - 8’ I{ + ;.,.e> - J b { I ,

And ior case (iii! :

a I AI, = V. - (Q - ~ . It) s 8’ 3

n M: = - - 0 J 8’ -

For design purposes the moments inay 1 ) ~ ;i~auiiirtl tlistribnterl as shown on figures IO, I I ancl 12 atid thc inaximum monients are given by :-

I-

November, 1936. MAIN ROADS. ~~

27

h’herc s and 1 arc the sides of the loaded arcs (scc: figures 10, X I and 121, i.e., 3’’ and 1’-8” for onc wheel of standard loading ;nid 3” and 5‘-8” for two.

F I G I O

Rritifo~ccriic~rt of Slab. The moments calculated above are suilicient to deter-

mitic the slah thickness and the reinforcement at the centre and edge sections of thc slab. Other stresses, however. arise from slab action which must bc con- sidered in the arraiigctnent of the reinforcement.

I he principal stresses at the edge and centre sections will hc parallel to the sitlrs of the slab, but it is evident that this will not I x the case at any other point of the slab. Tests show that square slabs, if insuficicntly reiiiforccrl for these atlrlitional stresses. fail by cracking near the corners at I)oth uppcr and lower faces. These cracks arc at aliout 43 degrees to the sides of the s la l~ and indicate that tlie pr i~~cipa! stresses at tlie coriicrs arc also at ;il)oiit 4.7 (legrees to the sides of the 5Iah.

Marcus treats the slal) as being made up of two series of strips and computes the relative deflections and the shear forces between the strips. He, therefore,

I .

6

FIG. I I

A E

FIG. 12

considers the stresses at any point as being divided into :-

.\ hcndii~g moment M, in thc direction of sides a. )f,, I , ,, b.

L\ torsion moment, say T, which is equal for both sets of strips.

28

2 /p\

‘ I

FIG.13

MAIN ROADS. ~

Vol. 6. No. 1 .

L U z

2 5 y / q 5 O

’\ \ \X//’ Y

I I I I

FIG. 14

From these riiotiieiits it would I x possible to tlerivc the principal stresses antl design the s l a l~ with rein- forcement along the lines of principal tension stress. .Practical considerations. however. rlemati(l that the rc- iitforccnient should lie ~):irallcl to tlie sides of the slal) ; to calculate tlie necessary reinforcemcnt l larcus re- coiiiitteitds the calculation of equivalent moments ii i

the directions of the sides n aii t l b ant1 sltrnvs that adequate reinforcemetit is provitletl if the steel is cal- culated from the eqiii\.alciit nioiiicnts.

E. = If. i T E, = M,) 2 T

cithcr sign may be taken to give the gre;iter stresses.

I t should he noted that the concrete slali is c:ilialil~ of carrying contprcssioii strrises i n any tlircct iot i and that the principal stresses at m y cither point \vi11 tin: exceed tliose calculated for the centre an t l ctlge scc- tions. antl the slal, thickness calcul;itc(l from tlic motnetits previously given for the centre and ctlge will be adequate.

Marccis has iiive4gatrtl tlie distriliution of tlie twist- ing mornent T and recoiiinieiids the atloptioii for de- sign piirpnses of the approximate distriliution :IS sho\vn in figure 13 for one quadrant. i.r.. the contours of the twisting nionietit form a pyramid with aliex “ I J ” ;m(l base “IZEOG.” The height at the apex “I” may be taken as:-

n T I I I ~ X . = 0.9 - M,

or 0.9 ~- M,, h I I whichwrr is thc greater. h n J

M, and Mb being the inaximum total positive moment at the centre.

I l c s i p of rro.s.s-girdcr.r. Cross girders spanning Iwtween the niain girders

should be designed as simply supported Iiy the main girders. I i more than two main girders :ire used the cross girders should be dr iyncr l as continuous l)cali7i. and consideration ~houltl also lie given to the effects of uncqtial loading atid deflections of the iii i i i i i gir(1ers.

I n the normal casc of two iti:iiii girders the cross girders are rtatically tletcrmitxite antl in Imlrling are subjected to the fullowing loads : - ~ ~

( i ) Dead load of self. ( i i j Ikat l load nf slab supported I I ~ girder. This

is tleterniinetl by thc gcomrtric:il coiictructioti given i i i figure 14.

(i i i) Live load. ’l‘lie wurst cas^ f i r r Iiiwliiig i n :i cross girder is \vhen the lai-Re whcelh arc placed directly over the girtlcr ; the girder will then carry the whole of these loads. ‘l‘l~e re- iitaiiitlrr of the lire loatl i n ; ~ > ~ usually be neglectctl.

The cross girders should also lie rlesignrtl for the torsion effects caused by the lietitling ntoliicn!s in the slab. In the case of interii~ediate cross girders the

29 _ _ _ ~ November, 1936. MAIN ROADS. - -

dead load moments a re cqiial and opposite in sign adjacent slabs supported hy the girder. and the tot31 nionient transferred to the girder will be thc total negative moment at tlie girder from live load on one adjacent slab panel less the portion of this moment transferrecl t u the nthcr adjacent slalr panel. In no l)ractical case mill tlie proportion transferred to the cross girder he more tlian 50 pcr cciit. ; the maximum twisting inotncnt in the cross girder. being one-half of this transferred moment. will not exceed 25 per ccnt. of the live load ncg-ative moment. The end cross girder will have to withstand the full negative moments from comliinetl live antl tlcatl loads, antl the maximum twisting tiiomrnt in the girder will be one-half the total negative momelit ii i the slab at the end cross girder.

7'01-sioit Lotrds 011 Mniit Girders It should also be noted that the negative bending

moiiiciits in thr slal) at the main girders will cause torsion in these members.

Thc niasinium twisting moment will be at the ends of each panel. antl will he one-half the total dead ant1 live iiegativc moiiirtits at the main girder for a single deck panel less the moment from the cantilever portion of the slal) outride the girder for an outside girder, or less the dead load negative moment from t,he other sla5 panel for an iiisidc girder.

Typica' i?'xnm$Ie. 4s a typical example, take a slab with-

Smaller side a=15 ft. 6 in. Larger side h=16 ft. o in.

a / h =097 b l a = 1.03

Slab thickness=g in.

Loading will be ils i n Fig. 15. Weight of slab=113 lb./sq. f t . ( p ) .

Prom Fig. 5 dead load moments are : M, ro .23 x r r 3 X15.5' M,, =O'ZZ x 113 x 15.5~ =G,ooo .,

=6,200 Ib. in./ft.

l\J',=-O.53 XI13 X 1 ~ ~ 5 2 = - 1 4 , 3 0 0 , , 1M',=-0.50 X I I ~ x15.52=-I:<,joo , , v =o.&

Livc load will be as shown in Fig. 7 (case ii). P=zxr j ,ooox1~25 (impact 25%)

' 3 7 , 500 lb.

=1.36 L I 64 R 0.835 X I j5* Q = 2 I ,600 R=Ig ,gOO

(0.55 ~ 2 1 , 6 0 0 - 0.10 x 15,yoo) =206,000 Ib. in.

FIG.15 LOADING F O R MAXIMUM' S T R E S S E S

=472,000 lb. in.

- _- 444,000 Ih. i n

=- 382,000 lb. in.

now b+f'= 16.00+0.25 = 1625

=21'17 U + S = 15'50+5'67

Vol. 8, No. I . - - 30 MAIN ROADS.

I6'-0"- b 1

N O T E : lDEAD+LIVE) LOAD M O M E N T S ( M OR U') S H O W N THUS TWISTING M O M E N T S ( 7 J " ,, - - - - - - - __. F U Y l V A L E N T M O M E N T S ( E O R L') . I,

FIG,

=o'g x 1.03 ~ 5 0 , 7 0 0 =47,ooo Ib. in.

Fig. 16 shows the twisting moments, bending moments, and equivalciit moments a t various points for a ccntral loading.

Tlic maximum cquivalcnt positivc momrnt E, parallcl to sides b occnrs ;it thc ccntrc. of thc slab and is ccliial to AT, (pos.), but rno rn t~~~ t s , nearly cqual to this maximum moment, occnr dong the diagonal of the slab for a dis- t m c e Ifvni thr ccntre eqml to about 0.3 time the length

The moment hf- is much smaller than M,,, and thc concrete stress and s!ab thickness will he govt:mcd by M b .

of tl1c tllagorlal.

16.

The maximum value of Ea: does not occur at thc ccntrc, but a t point 1, where it attains a maximum valac of 47,000 lb. in. =T (max.).

Thc section required for the momcnt M , is : Slab thickness total =9 in.

Cover below steel =I$ in. Effective dcpth of slah=hf (=t). Reinforcing steel = A . in. dia. bars :it 5 in.

Wearing surface =I 111.

centres. =0.47 sq. in. per ft.

Moment (illb) per ft. of slah =50,70o Ib. in. Mb/(d t* ) =93 Ib. per sq. in. Concrete strcss (from graphs) = O m Ib. per sq. in. Steel strcss (from graphs) =r7,900 lh. p:r sq. in.

=o.gX% of cona-cte.

I (The pcrmissiblc strcsscs are hgo and 18,ooo lb. per

sq. in. rcspcctivcly.)

For convenience in construction, this spx ing of 5 in. is maintained over a rcct;mgular portion of thr slab of sides equal to about 0.75 times thc sitlcs of thv fill1 shh, the arnuui i t of rcinforcc,mcnt hciug rcdnced bcymd this uczt. I his can convcnicntly bc donc by using in. bars ;it IO in. centres o w r thc full nrcii of thir d a h ;incl inti~rmi~diatc bars (about 12 It. lung in this cast') in the ;ma of higher moments.

'fhc n c p t i v c tiiomcnt M',] is about cqual to M , positive, and the same section can bc used. Equivalent

,.

November, 19 36. MAIN ROADS. 11

SECTION A A

FIG. 17

negative momcnts E',,, nearly as large as M',, occur for about 0.2 of the span b from thc supports, while small negative moments E'h extend nearly to the centrc of the span. To avoid cracking of the deck from secondary moment effects with no live load on the panel considered, it is advisable for portion of the negative stccl to extend over thc whole span. A n arrangement of through bars similar to the bottom through bars with intermediate bars over thc supports (about g ft. (I in. long in this case) in the area of higher moments is suitable. As tlic areas of high positivc ancl ncgative moments overlap, an arrangement with bent up bars is not suitable.

The moment Ma is much smaller than illb, and the concrete stresses, in other directions than M,, need not be

considered Thc maximum moment E, (positive), for the design of steel rcinforcement parallel to sides a , is 47,000 lb. in. pcr ft . a t point J . The effective depth for this stcie! is (@in- in., and $ in. dis. bars a t 5 in. cmtres arc also required for this momcnt.

The negativc moment aind adjacent negativc equivalcnt monwnts ii'n are greater than E , positive, but these moments occur n w r thc main girders which have to be connected to the slab by wid(: haunches for proper T bcam action. This increases thc cHcctive depth, and, in most cases, (lie stwl iised for positive momcnt will be adequate for thcse moments; if necessary a closer spacing of bars c m bc nsed.

Fig.-17 shows thc arrangement of steel in asinglc panel.

3 in.) =

32 MAIN ROADS, Vol. 8, No. 1

Major Construction l‘he following is ;i Iirief tlescription of several ini-

Imrtant ci~)nstructiuii n-orks :it presmt being carried out by the I>elrartment by tliiy 1;il)our. .\ iiiort. de- tailed review of each of these projects ivill Ire pi~l)lishetl ir: later issues of “Main I<oatls” when tlie works have bee11 completetl.

Cockwhy Range Deviation-Prince’s Highway.

Bct\vcen Termeil mid c‘iiclavliy Creek. a secticn of about I I 2 q miles in length. and situated ; IIJOII~ niitl- way between Rlilton and Hatem:iii’s Kay, tlie I’ritice’s Highway follows i i iiarroiv antl tortuous route over thc Cockwliy liangc. I liis section is to be alxindoned in favour of ii deviation having excellent aligntnent ant1 standard wit l t l i . Iocatcd on ;L route which 1x1. tlirougli easier country at :I lower level and at iio great distance from the existing rowl. The length of the deviation will be I O iiiiles. i.e., I $5 miles less than the Icngth of tlie section of tlic Higliw;:~ to he abatitlonetl. The niininiuii radius of curvature will he 850 feet. Work w;is coniiiienced in l~7eliru:iry, 1936. and over 100 meti are at present emplo!etl. It is anticipatetl that tlie (leviation will l)c completed :und openett for txf t i r late in 1937. dustless surface.

_ _

It will later Ire provided with

Yass-Canberra Highway.

’l‘lie road leading from the Iiutne Higl iw:~~ near Yass in it southerly clircction t n C‘;inl)eri-a f o r i x a n important linli connecting Caiilrerra to the \\

parts of the State, and also scr\~es triiftic prxtcding from Me1l)ourne to (‘atilierra via the must direct rmte, viz.. tlie Hume Highwiy.

Hitherto thr r o d has hat1 only a somewhat narrow nell-\\orn gravel pavement with poor alignnitant, gene- Ially unsuitablc for the class antl volutne of traflic wishing to iiie it since the r.;tal~lisliiiicnt o f the Federal Capital at Caiilrcrra. Following the proc1:inintioti of thc road as a State Highway. the I>ep;irtmc,it con- iiiencetl. in j;inu;iry. IO.?;, rcconstructirrn i ) ~ thy labour of the full length. viz.. 23 nlilcs Soo feet. TIW I’CCOII-

struetion comprises realignment wlierc~ ncccs\;!!-y. iri- c!uding two minor deviations. witlening. sul)erelcvation of curves. construction of reinforced concrete piix and box culverts. ant1 ~iri)vision of ii pavemetit t.olisistiny of a light premixetl 1)ituniinous macatlam surfact. course on a gravel 1r;ise coiirse comprising ?!le o l t l gravel pavement witlenetl atid itrcngzhenc~l xs re- quired, the Iiase course lwing se;ilctl. In order to I I I - I I -

vide the material for the snrfacc coii1-se. the 1)cp:irt- nieiit has est;iblislietl two quarries with cruslii~ig m i d hot-mix plants. The stoiic is qmrrietl. c r u s h d . heated aiitl iiiixetl with IJituniinritis niaterial at ci~cli ~ I I : I T ~ ~ ;inti then conveyed to tlic ro;itlway in lorries. ‘I lie y e - niisetl material i.; theii sprvad i n two Iayrrs tlir~~,l.gIi a

.standard steel tlr;iy-sprca&r. Tt is aiiticip:itcd that

Works in Progress. the work will he conipletetl at tlic etid of the mil-mer. In view of the iniportance of this road corinvction to the Federal Capital Tcrritory, the Co~nru,,. \rtaltl~ Governnient lias agreed to contribute twii-tliir,l!- ef the cost of the work. .\ sinlilar financial arruigemelit was tiin& i n respect to the Fetleral IligIiwaJ- Ivtween C’ollector and the Iiounrlary of tlie Federal C:ipii:d ’rer- ritory when that road was reconstructed several yeiirs ago.

Guyra-Ebor-Dorrigo Road.

I n hlarcli, 1936, tlic 1)ep:irtiiient coilmcnce~l by day labour the work of construction of ;I roail linkilig ( h y r a , Elm and Dorrigo, special funds for tiic pur- pose having been provitletl following a tlccisiiin tiot to liroceed with the construction of a railway. ‘lh total length of road between Guyra antl Dorrigo is 82 miles.

1 lie work is being carried out in two section. the section from (;uyra to Ebor in tlie Shires of (;uyra :incl Lhiiarcsq bciiig first uti(1crtakcn. (:iinstruction commenced at a point 12 miles 4.9% feet from (;uyr:i and is now proceeding it1 tiic direction of l’bor, the existing road from Guyra to 12 miles 4.5S0 fcct Iieiiig capalile of carrying traff;c pen<ling completion of the remainder of the work to l h r i g o . ’l‘he cxisting road Ixtweeii Guyra antl Elm involves hr alignment antl several open creek cro road. which over a consit1eral)le port does not follow the route of the oltl road. will provide escellent grades. easy curves antl will have hitlgcs or culverts at all waterways. i\t tlie present rate of pro- grrw the length from 12 niiles OPE SO feet to 3 0 iiiilcs will I J ~ completetl early in 1037.

The design provides for a 24 fret width of forn1;i- tioii, and a 16 feet width of pavenient. to lie of gravel construction. The road will serve as ;in important connecting link between the north-western Iiart of tllc State ant1 the coastal districts of Coff’s Harbour, Hel- lingen and Macksville.

r .

Narrandera-Griffith Road.

The construction of the Nar ramlc rd ;rifiith ro;i(I [Main Ruatl No. z j ? ) U-as commenced I)! tlic Ikliart- iiient by day labour 111 April. I ~ $ J . ’I‘hib road was oi- i - ginally proclaimed a main road largcly to servc the intercsts of settlers on the Rlurruniliidg~~e irrigation areas in providing access to the railway system. a i i t l this was achieved liy following a some\vliat intlircct routc. Commencing at Narrandera the mac1 crossc~ tlie railway at Yanco, again crossing a brmcli line o f railway west of Leeton. It practically touches tlie tiiain line a t Whitton and U further branch line at Yt.nda. At tlie junction of the branch systems :it Griffith, the road again connects up witli thc, rai1w;iy a n d once more crosses the main Hay line a t \\-illiriggic. 1 lie traffic is heavy antl the road lias Iiitlierto been r .

November, 1936. MAIN ROADS. ~

33 . -

largely unconstructed and impassable in wet weather. T o meet the needs of this traffic, special funds were provided for the work.

The construction in hand consists of earth forma- tion and the provision of an 18 feet wide gravel pave- ment throughout. The road will later he provided with a dustless surface.

Casino-Tabulam Road. The construction of the Casino-Tabulam road

(Trunk Road No. 64) has been undertaken from spe- cial funds in order to link up with the already coni- pleted work on Main Road No. 361 between hlallan- ganee and Bonalbo consequent upon the decision not to proceed further with the construction of the Casino

Bonalbo railway. The road construction work carried out during recent years in the development of the Cpper Clarence Valley has led to a heavy increase in the traffic brought on to the trunk road, strengthening and improvement of which has become neccssary to meet the requirements of this traffic, together with thc through traffic from Tcntcrfield to Casino. The completed work, which will extend over a length of 37 miles. will comprise a pavement 20 feet wide with a bituminous wearing course.

Construction work was commenced i n March, 1936, on the Casino-Mummulgum section. The Mumniulgum- labulam section involves the crossing of the Kich- niond Range, and field investigations are in hand to determine the niost favourable location for the per- manent route.

Shire of Upper Hunter: Trunk Road No. 62: Construction of Bridge over Wybong Creek at Bunnan.

The open crossing over [\;;).bong Creek at Bunnan has presented a serious obstruction to through traffic between Scone antl Merriwa (Trunk Road No. hz ) in the Shire of Upper Hunter, and also to traffic using the Scone-Bunnan-Kars Springs road. This has been duc to the fact that during the wet season the creek has been impassable for as many as three days at a time. A four-days’ inail service is in opcration np the Kars Springs road. and the iocal Shire Council asked that consideration hc given to the improvcment of con- ditions for traffic liy the construction of a bridge.

Surveys were carried out by departmental officers, and arrangements were made for the preparation of plans. A rcinforccd concrete bridge with four spans each of 37 feet. 43 feet, 43 feet and 37 feet would have heen the niost economical for this site. Information was, however, suhinittecl that large trees up to So feet in length could he expected to he brought down by floods, and in order to avoid the powibility of clcliris piling up against the I)ritlge, with consequent tlamage, it was necessary to adopt an arrangement of spans of 61 feet. 80 feet and 01 feet. The design for a continuous girder bridge was completed xcordingly.

The span of So-feet length in this bridge and in another structure in the course of rrcction ovcr Shea’s Creek i!i the Municipality of Mascot: are the longest yet attempted in New South \\:ales i n a reinforced concrete deck girder design. It is anticipated that the bridge over \Yybong Creek \vi11 he the first completed strncturc i n this State with a span cif such length.

I ) the use of the two- girder type of construction as being the most economi- cal, the girdcrs being 15 fcet 4 inches centre to centrc; ( 2 ) the provision of steel expansion rockers a t the

Features of the design are

abutments to allow for movement due to temperature chauges ; and (3 ) the use of compressible material inserted between girders and piers towards the front edges of the girder seatings to avoid crushing the con- crete of the piers following deflection of the girders under load. Abutnicnts of deck-slah type were adopted antl ample space provided fo; expansion with changes in temperature. A layer of I : 155 : 3 concrete was employed in the heavily stressed part of the compres- sion area of the girders above the piers, while the remainder of the concrete is I : 2 : 3 mix. Suitably spaced cross-girders are, of course, used in the design in accordance wi th the usual pmctice.

The Llepartment. in accordance with its present policy i n connection with the construction of bridges on trunk roads. has provided the whole cost of the work.

Tenders wcrc called for t!ic construction of bridge and approaches. and of the six tenders received, that of the Charles I~Iardy Contracting Co. Ltd. in the sum of f6.687 was accepted, the work being cornmcnced in April. 1936. No difficiilties of other than normal pro- portions were met with in the construction. As rigid foundations were required, it was intended to drive the piles for thc al)utnient foundations to rock at a depth of about 31 fcct. liut the ground overlying the rock proved niuch harder than anticipated and the maximum rlcpth thc piles could he driven was ahout 7 2 fcet less than intended. i.e., tn ii deptli of 10 feet. However, the piles have been driven very tight and the rigidity of the fouudation is sncli :IS !o lje suitable for the con- tinuous girder design adopted.

It is expectcd that the construction of the bridge antl approaches will be completed early in November, 1934.

Reconstruction of Pacific Highway North of Taree in the Shire of Manning.

Like the majority of the rivers of New South \\;ales which flow into the South Pacific Ocean, the Manning River, after emerging from the coastal ranges, hentls northwards antl flows through a delta of rich alluvial Hats formed 1)y silt brought down hy its flood stream. until it enters the ocean over :I sandy har, The Manning delta. which is divided I)! a iiumher of trihu- tary streams. may Ire said to conniiciice i i i thc vicinity of 'Taree ant1 to cxtcntl for about sixteen miles in ;in east and north-easterly tlirection until the sea is re;iched.

'The Pacific Highway traverses the delta, antl keeps within ;L short distaiirc of thc llanning from Taree to Coopernook, where tlie Lansdowne River. the last of the tri1rut;iry streanis. is crrrsscd. Owing to the rich nature of the soil, the delta is closely settled. ant1 road tra& is ctrinparativcly heavy in volumc. For the greater part of its length between Taree and

Coopernook, the Highway is below high flood level, drainage is poor, good gravel is ixit available within rmsonahle distance, atid the cost of m:iintaining a pavement of the local gravel ; incl shalc i i i cnntinuorisly satisfactory condition for motlern fast-moving traffic has becn very high. Rccnnstruction froni Taree to Coo1)ernoolt to provitlr a I)itunien surf;icetl Imvement. which could be depeiiderl on to give ; I I~crnlancntl\.. good antl easily maintained surfx-e. \vas therefore tlecitletl ( N I . using local materials as far as \ c w econo- iiiical. This reconstruction work. which is still in irrogress, has involved the solution of several intercst- ing Ixoblenis.

The first step taken w;is the close cuamiiiatioii o f tlie largc bridges. of whirh there are three, spaniiing the I>awson River. Ghinni ( ;hinni Creck. antl the Tandowtic Kivrr at Coopernook. in thxt ortler from Taree. The 1);twson River hridge was ;III old tiiiil)cr

"

Locality Map.

November, 1936. 35 MAIN ROADS. ~ ~-

truss bridge built about 1878, and its replacenient was decided on, the work being carried out in 19-32-33, The new structure consists of a central stcel truss span, with concrete beam spans a t each cntl, and a concrete deck throughout. This bridge was tlescrihrtl in the Fehrnary, 1933, nuniher of Mnin Aoatls.

Ghinni Ghinni Creek is a flood branch nf the Man- ning River, and is bridged hy a seven span timher beam bridge huilt in IOIO. This structure has still ;I number of years of useful life left, and, accordingly. it has not hcen renewed. However, tlic adjacent roatl- works are being so designed that they will fit in, with little extra rxpense. with the line of thc new bridge which will he ultimately provided.

The old bridge over the I a i sdowne River at Cooper- nook was found to require replacement at the same time as the Dawson River bridge. and was renewed in 1932-33. the work heing descrihctl in the April. 1933, number of h l a h Roads. The approaches to the ncw bridge pass over marshy groutld. antl fascines consisting of 1)undlcs of ti-tree stakes wired together were laid before the emhankmcnt filling was placed. Very little settlement has been observrd.

The roadworks have lieen coniniencrtl at the Tarcc end of the length. and the first problcm \vas to secure a crossinq over the Main North Coast Railway bvhich would eliminate the level crossing at the northern end of High-strert. Taree. After several schrnics l~atl hceri investigated. it was dccidcd not to cross the main line. hut to divert the Highway from High-street to pass along Victoria-street (the main street of Tareel and make use of esisting timber brid.rcs over Brown’s Creek and over tlic hranch railway line lead- in? to the deep-water wharf. This decision involved the rcconstruction of a gravel road throuyh practically unoccupied, but suhdivi(let1 hiqh eround on the COII-

fines of the niunicipalitv. from Brown’s Creek to a point 1 % miles from Taree Post Office. where th r original route of the Highway was reioincd. Thy investigations werc made and plans rreimred hy the Department. tenders for the work heing- aftcrwards invited l ~ y the Manninq Shire Council. The desien Drovided for a pavement of local shale of 9 inrhcs consolidated thickness. hlinderl with good settinq material to niakr 110 tlie rlrficiencv in cementiw nro- perty of the shale itself. and for culvei-ts of reinforced roncrete. Thr SUCCCSE ril l tendcrcrs were Messrs. Brooke Rros.. in the sun1 of fz.500. and the work is now almost complete. Stirfare treatment. which will be carried out hy separate contract early in the coniin!. summer, will consist of priming with tar and scaliiiq with fluxed 85/ roo hitnmen to the Department’s standard specification.

Owing to flle need for makiny a thorough i n v e s t i p tion of the best route to adopt for this first, section a t Taree. and for makinc rcsoniptions where the existing road was dernrted from in. ordrr to imnrovr alignment. it was founrl tlrsirahle to start work on the second sectioii before that on the first. The second section extended from the northern end of the first section for a distance of .? miles 2,000 feet towards Coopernook, and was completed early in 1936. General

1 i I

Improvement of Curve between Taree and Ghinni Bridge.

relocation on this Irngth was nut necessary. tlie only realignment required being the easing of existing curves, but pavement levels had to l ~ e designed to give the hest results in time of flood. Section I had only a short length Iwlow flood level-in approach to Brown’s Creek hritlgc-hiit a1)out S miles of Highway on the remaining sections I)ctwecii Taree antl Cooper- nook arc below high flood level of the Manniiig River by tlepths v a r ~ i n g from a few inches to over I O feet. The cost of raising the wliole leiigth of the IIighwray above the highest flood would be very grcat, antl would not he economically justified. high floods occur- ring. on an average, only ahout once in thirty years, whilst ordinary floods rarely cover the whole of the low sections. Small local dips existed, however, whcrc the depth of watcr \~oul t l interrupt traffic at times wheii the rest of the road could be travelled. and it was decided to raisc thew dips to the general leve! of tlic road on each side. Also. in order that all the low sections of thr IIigliway would be available for traffic together, after a hixh flood. the pavement levels on the flooded sections were so atljustcd that the flood waters u-ould rcccrle from them in approsimately the same time after the peak of the flood had heen reached. Records of floods in the Manning Rivrr show that the flood rise at Killawarra Iiridge, about r j miles up- stream from Taree, is ovrr 60 feet; at Tinonee. a few miles upstream. it is Z S fret ; at Taree itself it is 21 feet; at Dawson River, 17 feet: and at Coopernook. 7 feet, The flood waters rec.ede most rapidly where

Bridqe over Lansdowne River at Coopernook

36 MAIN ROADS. Vol. 8. No. 1 . _- -. _- the flood rise is greatest. and a point IO feet below high flood level a t Killawarra hritlge would be under water for a shorter pcriod than a point I O feet below high flood at say Taree. Consequently, it is advisable to hring the pavement level closer to high flood levcl as the mouth of the river is approaclicd, atid on this account the parement level immediately south of Daw- son River bridge has Ixen left 6 fret below the high flood level (F1.F.L.) at that point, whilst betweer Cundletown ;itit1 Gliiiiiii Ghinni I)ritlge it varies from 5 feet to 4 feet lielow H.F.1,. Eetweeii Ghinni Ghinni iiritlge antl Coopernook the. pavement level of the re- constructed road will rise from 4 feet I)clow H.F.T.. at the Iritlgc to 3 feet helow II.F.T,. at Coopernook.

The reco~istrc~ctin~i of Section z was carried out by the M;imiing Shire Coniicil by Day Laliour (with con- tracts for sriliply of mnterials) . the work consisting of the renewal in reinforced concrete. of all old tiniber culverts filling of d i p . adjustment of levels generally. the hoxing antl gravelling of the pavement arid land resumptions. Crushcrl shale from an existing quarry it1 Cundletown was used as a paving niaterial antl afterwards blindctl. as this rather hard material did not I)intl as expected uiitlcr the roller : \ i i t l traffic. The coiisnlitlated tlepth of the pavement is 7 inches, but

~~ __-- -~

whcre the existing pavement could be used as a base course, the new material was reduced in thickness, whilst spalls were nsed under the shale on soft ground at those points where iniprovemrnt of :tlignment neccssitatetl departure from the nld formation. 'The total cost of this work was fg.900.

h f t c r being traffirlirtl for some months, the pave- scarifietl, rolled. dragged continuously . and then surface treated. using a tar

primer and 85/100 bitumen for the seal coat. The aggregate applied to the bitumen was crushed litne- stone, which, is a liluish. tough. heavy material. that crushes well antl conlhines satisfactorily with the Iiinder. The s p r a y i q was carrietl out 1)y ctintract.

Section 3, from the end of Section 2 to Ghinni Ghinni bridge, is now under construction by the Coun- cil. the work beiiig similar to that carried out on Section 2 . whilst the next a miles section f r t m Ghinni Ghinni bridge towards Coopernook is being surveyed, anti its reconstruction will be commenced ;it an early (late. The remaining sections will he undertaken as i m i s heconie available, until the whole Icngth of 15 miles across the flooded flats from Taree to the northern elid of Coopernook Village has I)cen com- pleted.

Tenders Accepted. The following Tenders (exceeding i300) were accepted by the Department during the months of July, August,

and Septrmhcr, 1936:- ~~

Kame of .4monnt of Accrpted Tenderer. Accepted Tender. Council. N'ork.

- -

hfETROPOLITAA' DIVISION. L s . d.

Preparation for occupancy of four opcnings under the 4,529 I? 0 1 ' '_ I Sydncy Harbour Bridge-Northern approach.

LIF1,F.R N O R T H E R N I ) I V l S l o N .

Guyraand llumar- 175 ! 1:cncing of road boundaries between 13 m. and %z 11:. W. Campbell so1 14 Y euq Shires. 1 . 1,530 ft.-Guyra-Ebor. I Gooding.

J.O\VER SOUTHERN UIVISIOS

i o Keconstruction I~anfiy-TugKerdh--Siipply and delivery Brooke Bros. ... 1.575 0 U

1,3<9q 6 o

r.o.50 0 0

- . I . . . I 1 0 1 :.nnr;t&tion of reinforced conrretr hridge over Sapling Gam ti Jenkins

of 3 -00 cub. yds gravel.

Creek.

l iddel l Overhrirlga and bInswel!hrook Shire horindnry.

dclh-ery ~ . > O C I cub. yds. gravel.

(,,io0 cub. yds. xi-avel.

Erina S . ... Hastings S. :::I Patrick Plains S t , Supply and delivery of 7,000 cub. yds. gra\-el between Tracey & Anderson . . . I

. , . 'J I<cconstruction norlh of Ra \ cnhv urtl~-Supply and Lcslic k 1;orgic . . . , 577 1 0 0

boo 1 2 ti " ' I _ . _ , I<rconstrnction a t Carnber\velI- -So]q>ly and clclircry \Vest Pc .\rinitaRc

KORTH-\\ 'ESTERX L)I\'ISION.

I3ridge over Hunter River at .\berdeen--Supply and A. Goninan & Cn. 1.td. 897 7 6

I<edecking of bridge over Ilunter I<iver at Aberdeen . _ . Chas. Hardy Contract- 2,987 0 0 dclivcry of steelwork.

ing Co. Ltd.

Upper Hunter S

37 _I

November, 1936. MAIN ROADS.

Tenders Acceuted-continued.

Work. Name of Amount or 1 Accepted Tenderer. Accepted Tender.

f $. d. SOUTHERN DIVISION.

Gunning S. Supply and delivery of 1.200 cub. yds screenings Downes Bros. ... s j o 0 0

3.67X I 0 " ' I .\lnmhulla S . : : : ~ I Formation and paving of approaches tobridRcovcrRrogo G . A. Armstrong :::I River.

Yanko ... . . _ I 14

. . . I 1 4

... ''7

... x 5 1 ...

1 .

SOUTH-WESTERN DIVISION

Supply and delivery of 4,800 cub. yds. pave1 . . . . . . \IcDonald Bros. . . . Supply and delivery of 3,500 cub. yds. gravel . . . . . . E'. Bcalc . . . . . . Supply and spreading 7,000 cub. yds. gravel . . . . . . E. J . Fealey . . . . . . Supply and spreading 3,580 cuh. yds. gravel . . . . . . A. J . Hill & Son Pty .

Supply and spreading 5,460 cub. yds. gravel . . . . . . F. Discenga . . . . . .

8,231 l in . ft. of gravel consiruction in four sections hr- V. Phipps . . . . . .

Ltd.

Supply and spreading 4,370 cub. y& gra\,el . . . . . . A. J. Hill & Son Pty. 1.td.

tween i o m. 2,000 ft . and 59 m. 2.500 ft.

\VESTERN I l i v i s ~ o a

Supply and delivery of 3.180 cub. yds. gravel between

Ilnston to Gol Gol-Construction and completion of 19,ooo

linston t n Gol Gol-Construction of II .OHO lin. f t . of J . A. Purtill . . . . . .

Balranald-Ivanhoe-Construction of 36,000 lin. f t . of J . O'Connor . . . . . .

lcannia-Construction of 24 causeways ... C. C . Gillies . . . . . . Oxley-Penarie road-Construction o f 10,107 lin. ft. of G. Johnson . . . . . .

C . C. Gillies

F. Silvester

. . . . . . Florida and Barnato, and botwcen Cobar and Hillston.

lin. ft. of formation and gravel pavement and 18 pipe culverts between I j m. 3,734 ft. and L I m. 1,614 f t .

gravelled formation. and fifteen pipe culverts.

. . . . . .

roadway, etc. ~ ~~~

Y8o n o 415 I Z 0 '133 6 760 15 o

750 10 0 Bo1 3 4

1,018 0 U

The following Tcnders (over L300) were accepted by the respective Councils during thc months of July, August, and September, 1936 :-

~~

I Name of I Amountuf Arrepted Tenderer. 1 Acceptcd l'cnder. Council. 1 R;:d I JVoork.

~.

i s. d 3fETKOPOLITAN UIVlSloN.

Abercrombie S. . ._ ; 252 I Construction of 1t.C bridge over Triangle Flat Creek . . . I IV. )'I. Scott . . . . . . 1 r.264 18 7

I.O\VER NORTHERN Div~sroa.

Kearsley S. . _ 2 1 8

Manning S . ... IO

Muswellbrook S . ...

Tarro S. ... 2 2 0

Walikobba S. _ _ . 1128 Wallsend bl. . 217

... :::I 2 1 0

Boolooroo S . 338 Boomis. ... : : : I 232

. . . . . . . . I 2

. . . . . . . . 12

f 1 B.H.P. By-Products 1 Pty. Ltd. Supply and application of tar and/or bitumen ., .

Reconstruction between Taree and Ghinni Ghinni Bridge

Supply and spraying of binder

1 J . .A. Stewart . . . . . . Srction 3.

. . . . . . . . . , Supply and application uf binder . . . . . . . . . . . .

Supply and delivery 3,500 cub. yds. gravel bctrvrcn A . J Stevens . . . . . .

Reconstruction Church Creek Bridge . . . . . . . . . Moehan B Wisken

R.C. Culvert fPlatts Bridge) . . . . . . . . . . . . ...

Williamtown Store and junction M.R. 2gX.

. . . . . . . . . . ii ... . . . . . . . . . . . . Reconstruction Armstrong's Bridge., Construction of 3 causeways Beavis Bros.

UPPER NORTHEKN DIVISIOP.

lieforming and loaming 160 chns-igf m. to z i t m. . . . J . A . Hefercn . . . . . . Formation and culverts . . . . . . . . . . . . . . . Barney & McIirnzie ... 240 chns. gravel construction-zo m. to 23 m. . . . . . . F . flakon . . . . . . I M chns. loaming-3zm. to 34 m. . . . . . . . . . . . . . . . . . . 175 chns. reforming and gravelling 23 m. to264 m. Supply and delivery 2,400 cob. yds. gravel . . . . . . G. hleale . . . . . .

. . . . . . . . .

3q2 16 o

i .103 16 X

y z ~ 19 2

454 0 0

334 16 0

415 16 I O

Road Connril.

Rdlingen S . . . . . 1 1 , )

. . . . io

... Ila1 Casino hl. ... 1 4 1 )

Dorrigo S . ... IlC,] 04 I

I 2 0 >

. . . IIC)

... 1 2 0

Lismore \ I . , . .

Nymboida S . . . . I L I Orara S. . . . . . . 1 2 1

Tintenbar S. . . . 146

Tomki S. . . . 64

CncklrurnS. ... (1 ... "3

Coonalrarabran S. I I

... 1 3 ,

... 1 1

Iivcrlxml I'lains S ~ 357 . . . I I l l 2

5 .i : : : ~ I 1

7 Amaroo S . _. . Bojian S . . . . I l " 3

Cobbora S . 7 . . .

Cilgandra S . ._ . 205

. . . . si, Gooliang S. _ . . 1003

... 1151

... 56

Jrninlong S . 5 0

I.yndhurst S. 245

I

. . .

. . . Macquarie S. . . . roo:.

7 ...

Marthaguy S . ... I O R I

Waugoola S. ... o Weddin S.

MAIN ROADS.

Tenders Accepted-continued. ___ Name of Amount of '

1 Accepted Tenderer. 1 Accepted Tender.

SUKIH-~<ASTERN LhvlsIon. l<econstruction betwrrn Hellingen and lialeiglr--I nl. Brady & O'hleara ...

Constriiction of r,HW lin. f t . . . . . . . . . . . . . L). Caratti . . . . . .

H.H.€;: By-Products Supply and spraying tar m d bitumcn . _ _ ..,

Constriiction of pipe culverts . . . . . . . . . . . . Chesterfield & Jenkins ...

I3itunien surfacing ol sections a t ('off's Harbour, Coramba llitumen Services Pty.

rWuiiicn surfacing ol I $ miles roadway iicar Dorrigo Supply and delivery of 1,863 cub. yds. crushed metal F. Gilbert . . . . . .

Supply and spraying of bitumen . . . . . . . . . . . . A.H.1'. By-Products1

.! ,2%) f t . t o 8 ni. 2 , 1 2 4 ft.--Earthworks.

Supply of screened aKgregate . . . . . . . . . . . . . . . . . .

{ I'ty. Ltd.

and Glenreagh. l , tc l . ... Clicsterficld & Jenkins.

Iretween zoi ni. and 30 i n

Pty. Ltd.

Supply and spreading 1,400 cub. yds. gravel between John Hayes 4.75 ni. and 9'75 m.

I<econstrnction and improvement hetween 6 m. 21: chs. E. Watts and 6 m. 50: chs., and between 6 m. 68 chs. and h m. j.6 chs.

IWonstruction hctuccn 4 ni . 4.550 ft and X m. 4,550 ft.

Constniction tiniller beam bridge a t 3 Mile Swamp ... lirnncdy 13ros. ... . . . . . .

. . . . . .

Murray & Co. . _ _ . .

~ O R T H - \ \ ' E S T E K N I ) l V I S l n N .

('on.;truction of dcviatiun ;it foot of Moonbi Range Supply of screenings tar surlacing on Tamworth- Sulphidr Corporation"'/

Clearing, fomiing and construction of culverts 5 111. east of H. V. Hardy ...

.,. I'retus & Jenkins

.\ttunya section. I.td.

Coonabarabran. I<csliccting between m. and 6$ ni. . . . . . . . . . E. \V. Hall ... I:orming, gravelling anti culvert constructioi~-(i in. 2,900 I<. O'Ncill ... I;orming and gravelling i~ . joo f t . near Rarney's Gully . . . 1). \I&ee ... Gravcl construction and plpe culverts bctwccn q.6 nl. and W. H. nlarsllall

Constrixtion j . 3 0 0 l i n ft. gravel pavrment, pipe a n i 1 ) . .\lc(;ee _ . .

Supply and deliver). of 1,205 cub. yds. of screening- . . . I t . C. Harber ... 1'nrni:ition and gravel w a r Breeza I.evpl Crossing . . . I<. Gardner . . . Hridge over Ihlton's Cwrk at Ked Clay CIIIIV, bf m. fron . . _

Construction of culvrrt . . . . . . . . . . . . . . C. A. Leahy . . .

f t . t o IO m. 1,347 ft. west of Coonabarabran.

12'.5 111.

concrete culvert.;.

R. O'Seill Tammortll.

SiippIy, ilrlivery a n d spreading 01 gravcl . . . . . . . . . F. S . Barhe .. .

I<cconstructinn l ~ ~ t w w n 203 m qoo It. and 204 m. 300 Clearing and grubbing .. . . . . . . . . . . . . .

< : R N T R . A L - \ ~ E S T E R N 1)IVISION.

...

Coristrnction of pipr a n d box culverts with earthworks J . I.ighezolo

Sqiply, delivery ancl spreading r.350 cub. yds loam and T. A. Miller

. . .

... bctwccn 2.30 m . 1 .155 f t . and 2 4 2 111. 2,428 ft,

1.144 CUI) vds. "r;lvel. . . . . , Cnnstruction of tinihrr beam bridgr ovcr .\larthaguy Sulliwn l h s . ... I~~~r lung le -Numul l a~ Gravrlling bctween I I m . 5 chs. and W. Wilson _.. ~ ' ~ ~ r l d - I i a d u n g l e - C o ~ i ~ t ~ ~ ~ c t i o n of L m. 2 , 1 5 6 lin. ft. . . . Griffiths & Campey ... I Construction of K C . Ilox culverts a t I S k. 48 chs. and Western Concrete Co. . . . '

I (e-ali~nment and regrading L m. 4.300 f t . to 5 m . 1.560 ft. 1'. Hest . . . . . . . . .

Construction of R.C. bos ciilverts . . . . . . . . . R. Croniack .~r th i i rv i l le~Geur ie~~~Coi is t ruc t ion between H m. 2.600 ft 'l. A. Miller . . . . . .

and I O m. 4,802 ft . Construction uf 5 . 6 ~ f t . of gravel pavement, including A. I i . Wheeler . . .

cillverts, drains and fcncinx, between 2 2 2 m. and 2 2 6 m., o n the Rlolnn~-\Vellington section.

'lop dressing bctween 27 ni. 14 chs. and 3" 111. . . . . . . J . 11. I'uckeridge ...

Construction h e t w r n I X G ni. 400 ft. and 186 111. 3,500 f t . Downes Bros. . . . . . . . I

Crcck at 32 ni. from Dulho.

13 111. 53 CllS.

15 in. 20 chs.

from Forbes. . . . . . .

Supply and spreading gravel. etc. . . . . . . . . . . . . l i . I.'arquharnon . . .

I$'orming, draining and gravelling . . . . . . . . . . . . J. Rush . . . . . .

...

...

...

...

. . .

...

...

...

...

. . .

...

...

. . .

...

...

...

...

1,219 13 o

401 6 I I

31'1 13 5 1,Oj . j 5 0

1,,321 2 n

74x I O 0 1,096 14 8

058 0 9 ojo 0 0

November, 1936. -

~~~ ~~

Name of 4ccepted Tenderer \ l w h

~~

. . . liihhenliike S . 5 3 z i 4 . . . 53

... ' j 4

Goodratlig1,er S. .. zj.8 Alonnro S .

. . .

Amount of Accepted Tender.

Iil;rn<l s. ... . . . . .

. . . . .

liurrnngong S Coolamon S .

Conargo S. Corowa M

Ilolhrook S

. . . . . . I:orniing and gravelling I)clcgatc-liorder section Reforming and gravelling between o in. and o in . 1 , 3 y ) ft.,

Construction of R.C. culvcrts at 0 m. 20 chs. and T O ni. ... and between 1 m. i , q o ft. and I m . 3.707 ft .

. . . . . . Constrnction of H.C. J3ox culvcrt a t 33 miles Supply and delivery of 4.32X cub. yds. gravel bctmccn

1.75 111. and 38.50 m.

. . . 5 2 . . . I 5 2

... l 0 L . t

. . . 1010

. . . 1 0 2 q

. . . "50

.... ITSS

... 5'1 _ _ ' 2O'l

, , . 278 !

. . . 12;s

. . . : 2 j x

... 1 : : ~ 1; 12.5

5'1

... 0

... 0

. . . ( I

...

296

. . . . . . G. \Yarn? . . . . . .

IV. D. JlcUonalrl ... ...

C. Shepherd . . . . . .

. . hingal.

Construction of bridge ovcr Shaking Bog Creek . . . . . . J . I<. Hyland Clearing, grubbing. earthworks, gravelling, culverts, ctc.. .. B. Robinson Gravcl construction with cnlvert hetween I O m . 5.200 ft. R. Dalitz

I.oammg. etc., o m. to 2 m. 2 j chs. . . . . . . . . . . . . A. Robertson I.oaming. etc., 2 m. '7 chs. t o 4 m. 54 chs. I.oaming, etc., 4 III. .54 chs. t o 7 m. . . . . . . . . . . . . h. Robertson Xo chs. reiorming, resurfacing with Ioani and rolling .. . C. \Icl)ougai loo chs. reforming, resurfacing with loam and rolling .. . H. V. Gready Reforming, resurfacing, etc.. 100 chn. . . . . . . . . . F. P. Barhcr

and 11 in. goo f t .

. . . . . . J . Connor

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Sydney Harbour Bridge Account. Incomc and Expenditure for the quarter ended 30th September, 1936.

INCOS~E- Road Tolls . . . . . . . . . . . . . . . Contributions for Railway Passengers ...

Tramway Passengers . , , hyCcnincils . . . . . .

Rents from Properties . . . . . . Miscellaneous . . . . . . . . . . . .

EXPENDITURE- Cost of Collecting Road Toll ... Maintenance and Minor Improvement .Maintenance of Properties . . . . . . Administrative Expenses . . . . . . I.oar Clzarges-

Interest . . . . . . . . . . . . Exchangc . . . . . . . . . Sinking Fund . . . . . . . . .

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j l ' , . i l l 31s I 1 s 350 I Z 6

498 1, 7 r , o ~ g o o

470 o o 942 I ? H

421 19 o

0 4 7 1 3 0

364 5 0

911 I 8

' ) j X 15 6 470 8 0 30X I 6

3.55 0 0 3 7 4 0 0 353 0 0

3 1 2 0 o

393 6 X j6o o o

s. d . . . . . . . 53.929 o o . . . . . . ... 26.309 o o . . . . . . . . . 1 3 . 5 ~ o o . . . . . . . . . 16,500 o o . . . . . . . . . 1.264 o o . . . . . . . . . Z O O

LIII,594 0 0

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. . . . . . . . . 7.909 0 0

... ro.500 o U

... 9.250 o o 98.500 0 0 -

40 MAIN ROADS. Vol. 8. No. 1 .

Payments from the Road Funds for the period 1st July, 1936, to 30th September, 1936.

~~~

HEADING.

COUNTY OF CUYIRERI.ANT) MAIN I<o.rus FUND-- Construction of Rodds and Bridges . . . . . . . . . . . . Cost of Land licnumptions . . . . . . . . . . . . . . . . . . illainfenance of I<oads and Bridges . . . . . . . . . . . . Interest and Repayment of I.oans . . . . . . . . . . . . . . . Survey, Ilesixn. Supervision and Administration . . . . . .

Total . . . . . . . COUNTRY MAIN ROADS FUND-

Construction of llonds and I3ridges, including Iiesinnptioni Maintenance of I<oads and Bridges . . . . . . . . . . . . In teRst and ~ e ~ d y n i c n l of Loans . . . . . . . . . . . . . . . Survey, Design, Supervision and Administration . . . . . . Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . .

Total . . . . . . . . . . . .

I)EVEI.OPMENT ROADS !?UNU-- Construction of Roads and Bridges . . . . . . . . . . . . Survey, Design, Supervision and .i\dministration . . . . . .

Total . ._ .. SUMMARY ALL ~XTDS-

Constrnction of Roads and Rridgcs, including Resumptions Jlaintenancc of Roads and Bridges . . . . . . . . . . . . Interest and liepayment of T.oans . . . . . . . . . . . . . . . Survey, lksign, Supervision and Xdministration . . . . . . hliscellaneous . . . . . . . . . . . . . . . . . . . . . . . .

GRAND TOTAL-ROAD FUNDS

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f s . d _. . 20,040 10 4 ... 5.540 16 1 1 . . . 47.254 1 3 0 . . . . 2 2 . I I c ) 1 1 x . . . I <),OX1 1 0 x

. . . I I 3 , Z O 8 1 j 2

. . . . !4~ ,6791j 4

. . . 20,471 1 7 X

. . . 1 8 . ~ ~ 6 17 I I

. . . 276 I1 0

Sydney Harbour Bridge

Enclosed Arches

Southern Approach.