i M R l N F! A Record of the act

Department of

ORIS vities of the Vlain Roads, N.S.W.

Snow Scene on the Jindabyne-Kosciusko Road, three miles f r o m Mt. Kosciusko.

JUNE 1947

MAIN ROADS. ~~

Issued Quarterly by and with the Authority of the Commissioner for Main Roads.

Vol. XII No. 4 Sydney, J U M , 1947. Price: One Shilling.

CONTENTS.

Tlle I’rincc’s Highway ... ... ... ... . . .

Principles for Ucsign of Son-rigid Pavemcwts . . . . . .

Canberra Aerodrome C~inst~uction of Runways . . . . . . . . ... . . . . . .

Origin aritl Ikstinntion Survey of R o d Trallic in the City of Sydney . . .

Payments from the Road> F i i n d ~ for period 1st July, 1946-31st Mari~li,

. . . . . . 1)evelopmcntal lZoads and 1)evclopIncntal Work.; . . . . . .

Sydney Harbour Bridge Account ... ...

S e w \‘esse1 for Scwca.;tle-Stockton 1;crn-y Servicc . . . ... . . . . . . . . . . .

. . . . . .

... ... ... . . . . . . ... ...

P A ~ ~ E .

97 . . . . . 105

. . . ... ... . . .

. . . . . . . . . I 1 1

. . . . . . . . . . I10

. . . . . . 1.21

. . . . . . . . . I22

’947 . ’ ’

. . . ... ... . . . I20

. . . . . . ... . . 126

. . . ... . . . . _ . I2 j

Additional copies of this journal obtainable from the-

Department of Main Roads, 309 Castlereagh Street, Sydney, New South Wales, Australia.

ROX 3903 G.P.O. Telephone : M 6231. Telegrams : (‘ Mainroads ” Sydney

Annual Subscription, 4/-; Post Free.

Reprints of any portion of this publication, unless specially indicated to the contrary, may be made provided the exact reference thereto is quoted.

The Prince’s Highwav.

The Prince‘s tlighway. so named i n 1921 to com- tiicmorate the vi,it to .\ustralia of the tlien F’ritice of \\-ales is the m:tin IiigIi\vay serving the coastal are;is of New South \\.ales, for a distance o i 346 miles front Sydney to the \:ictorian horder. IVith tlie I’acific Highway I(J the iiorth. tlie Prince’s Highway forms p i - t o i a continuous cuastal roatl linking Bris- I):une. Sydney. Melbournr antl Atlelaitle.

l inowii i~rigitially ;is the “South Coast Road,” it w2.s ~rin~claimetl in :IS State Highway KO. I . lieyonil the tcriiiinus of the railway at Nowra the I Iigh\viiy provides the prinrilial mentis of transport for the toiviis and tlistricts lying I>etwcen tlie Shnal- haven liiver atid tlic \.ict(rriaii border. a distance of 244 miles.

Comniencing at the outskirts of the City- of Sydney. tlie Iligliway passes tlirougll the highly devclopetl industrial arid rcsi~lc~~tial iireiis Iietween the City atid the (;eorge’s liiver ant1 tlieii follows the ridge of tlie Illawarra Range to tlie liulli I’ass. Frnrn the ioot of tlie l’ass to Nowra, tlir roatl proceeds first through tlir rapidly expanding iiitlustrial arcas of Bulli and \\~olloiigiiii~, and then passes through country consist- ing gencrally o i fertile alluvial flats or rouiided hills ( i f volcanic soil and with iiormally high rainfall. This ;irc:i is ~I~IllOSt entirely devoted to agriculture. particu- larly dairying. but tiear E;i;um;i thrre are several large liasalt quarries.

From Nowra tu the Victorian hortler, the Highway traverses thr hilly country, much o i it heavily timbered, with f rcqucnt agrieultural areas usually on or associated with stream valleys. I n this tlistrict the principal industries are dairying. tiiii1)er getting a id milling- and Iishiiig. and there is also consitlerable tourist activity duc to tlie attraction. fur recrratioti. o f the succession nf 1)eautiful beaches. tidal lakes and bays ;ilong tlie

51 far as is known the earliest travellers to follow the liiie of what was Inter to hrcomc tlie Priticr’s

\\Il(lle’ I J f tllC Coast l i l l? .

5812G-I

I ligliway. were soline sliip\vrrcketl sailors. seventeen in iiumher. who landed at I’oint I I i coiiiiiieiicrd to walk nortliwartls along tlie coast. 400 mile.; to I’ort Jaclison. Only four survived atitl. to invcstigatc tlic infuriiiatioti giveti by ttiein to the authorities. Governor Hunter despatched Bass who rnterrtl tlie Ikga River on rSth Ilccciiilier, I j97.

In ISIS, only thirty years aftei- Captain Phillip’s establishment at S y d n e y of the Iirst settlement in ;\ustralia, an attempt to penetrate irom Sydney to the South Coast was made by surveyors Janies Meeliaii nntl Charles Throsby. The party set out from tlie Moss \.ale district but, o n rracliiiig tlic Shoalhaveil liiver near Ilarulan. they foiund tlie country impenetrable antl it \vas ;igrretl to divide the party. Throsby returtictl to Bundanoon Creek from whence he penetrated to the coast at Jervis Bay. Meehan ;itteinptrd t o cross the Slioalhavcii upstream irom Throsby’s crossing. but failing to do so: turned inland to discover Lake Bathurst ant1 tlie Goulburn Plains. :It al)out tlic same time ‘1’hrosl)y rliseovered the track f r i m the soutlirrii districts tlown the lllaivarra Range to Ilapto.

The earlier South Coast scttleinents were almost entirely dependent upon sea carriage of goods atid passengers. Organised coastal sliipping coinmciiced i n rS5S with the first steariisliip of the Illawarra and South Coast Steam Savigation Compiiy-a flat- liottoiiietl, wooden patltllc whceler of 101 toils. As each settlement expanded roatl connection between adjacent centres became necessary and. with the pass- ing of time a iiiore or less cuiitiiiuous track along the coast was gradually tleveloped.

By 1&)3. a railway had Iwcn constructed as far as the Shoalhaven River at Nowra. The line dit1 not cross the river and its terminus rciiiaiiis at Bomaderry 011 tlir northern hank. :\ railway irom Goulburn to Cooma \vas opened for tratlic i n IMC) and, in the batile year. a mail roatl \viis lruilt t i~(1~1gl1 Nimrriita1)el ancl

~~

90 . ~

. ~- MAIN ROADS. ~______ Vol. XII, No. 4.

Bulli Pars.

road varied i n \ri(lth from 43-ft. to 00-ft., tht: variations i-cs~iltiii~ frcrm inc~rmplrte efforts at \vi(lrniiig in the past.

From Sut1icrl;mtl I(I tlic \‘ictol-iar liorcler the concli- tion of the road gmci-ally tlirouglr~rut its length, apart i r ~ ~ i i i wiiie iiolatetl lengths on which work had been carried out was far I r low tlic recliiiretiiciits of :L iiiotlern highway. 1;rr)m I<tlc.ii to tlic Victorian 1)order the r r d was little Ijetter tlian ;I liusli track through tlelisc forest country.

The prol>lem faced iii 192;. therrforc. was a fomiitlahle one antl complete reconstruction of the I’riiice’h Highwaj was seen to be iiievitable. In arlditioii the provision of new lrritlges in replacement of trltl structures. ant1 at sites where britlges had not previously existed. was required 011 a11 extensive scale. The policy atlopted i n resprct of Iiridges \vas that tlie order tri Irrefcrenze in the selection of bridge \vot-ks LO

IJC untlertalte~i should Ire as follnws :-- ( i ) Iirplacernent of bridges washctl away by

ttootls. or where tlic I>ridjics Ii;tve l)eeii closet1 to traffic (I I IC t o their unsafe condition.

( i i ) lieplacetiient of hitlge:; :it the end of their useful life.

I i i i ) ~‘irnstrncti~rii I l i lrridxes where mrne I)rc,vinusly existed.

99 -__ ~ ~~~ ~

June, 1947 MAIN ROADS.

WOLLONGONG

MAIN ROADS. ~ ~~~~

Vol. XII. No. 4. ~

Cutting south of Dignam’s Crrrk in Mumbulla Shire.

SYDNEY TO NOWRA. From the ci)iiillieiicelllellt of the ?riiice’s 1 ligliivay

:It (‘it! ro:itl t o Newtown l I~~ i~ ic ipa l i t y , the pavement was reconstructed with an aslihaltic coiicrcte iveariiig coiirstt O I I ;L ccmeiit concrete fouiitlatioii. i i i eo-opcratiirii with tlic Sydiiej. \lutiicil)al (‘iiuncil.

tion. i n Newtown AIiiiiicipaIity. had a wi~ent wliicll (lid nu l call fiir rarly

:ittcnti~rii. Iiut within thc Municipality of St. l’rtcrs. for a distance of two iniles north of Cook’s River the old ~)avemetit o f waterbound macatlatn was w i i - i i out and in a r ( r u ~ h cirntlition. The improvenment o f tliis scctiim w;is recogi:ised as Iieiiig o f great urgency and widening of the road to ai1 overall width of So-ft. ;itid thr coli- structioii o f the ful l width of the carriageway (56-ft .) in :tspli:iltic coiicrrte on a cement concrete base were put it1 h a i i t l at wice. The cost of this work . inclutling

irp laiitl resumptions was fmo.00~). Frotii Cook’s liivcr Bridge tu the (k i rge’s River

the ro;itl Ii:irl lieen reconstructed by tlie I ’ul)lic \Vorks I)cli;irtiiient prior tu the estalAishnient of the Main I<oatls lioard and 110 further extrtisive work was coil- sitleretl iirccssary.

The (;eorge’s River was at that tirne crosietl 11y a vr1iicul;ir stc:~m ferry plying between Tom Ugly’s I’oiiit : ~ t i t I Sylv;iiii:i. Tlir gi-owing vc-iluinr of m i t [ i r

traftic. particularly at week-ends ;ind 0 1 1 holidays. at tiiiies resulted i i i long delays Iirforc vrliicles could cross the river. I n 1925. therefore. rhr t~~tistruction o f :I Iiritlgc w n ~ untlrrtaken I)? tlic Sutherl:~titl Shire Cimicil. The I)ritlye \vas tlesipctl liy tlic I )e~)artmeiit o f 1’iiI)lic \\.iirks, N.S.\\. .. and coiisihti t i i six main sp:Iiis irf sterl l’ratt trusses, cach of 22.i-ft. length, carried 0 1 1 concrete cyliiitler pier4 ; a1<1 tlircv c p f t . long stecl plate girtlrr approach spans. 1 IN. ro:itlway is 30 ft. wide ;inti there is otic footway. ’Thr Iiridge \ w s conipletetl in I ~ ( J and has since I)ecn olieratetl as ;I tnll I)rirlge l)y tlir Sutlierlantl Shirr Coullcil.

l‘roiii the Gear-gc's River h i Sutlirrlatitl he roadway hat1 Iieen recently reconstructed in bituniiiious mac:itlam a i i i l wiis in fair urtler, but from Suthcrlaiitl to the top o f Ihilli I’ass the road was surfaced oiily with gravel and improvement was required in respect o f Iiavcment a t d also of aligiiniriit. I<econstructioti was conin1cnccd in 11127 ;tiid, except for a pcritd in 193 I . \\‘ah carried on continuously until hlay. 1933 Iiy which ti111c tlic Icngth o f 25% miles. from the George’s 1iivc.r t o the top of the I’ass had lieen recuiistructctl ai1<1 pi-oviilril with a Iritumiiious hurface. Several tleviations had Iieen

.ary to secure improved alignmciit OII this section : i i i i I cotisideral)le earthworks U crc iiiviilvcd. The cost o f the \vcii-l< c;irrirtl <rut [ i n tliis scrti~in ; i i n o n i i t r t l to

,.

f l ~ ~ 2 ~ o I N > .

June, 1947 MAIN ROADS. 101

pThe Bulli Pass which fornietl the link. antl the only inimctliately availahle (me. between the precipitous edge of the Illawarra Range. 1 .mo-ft. in height, and the 11I:iwarra coastal area. had always been a ditficult ol)staclc tu traftic. both horse-drawn aiid motor of the earlier type. Several endeavours had been made to locate an easier descent to tlie coast. ])ut without success. Het\vcen 1029 antl I 033 tlie widening and inil~rovenient of alignment of tlie I’ass were given attention and tlie work carried out during this Iieriotl has made the l’ass easier and safer t o negoti;ite because of the improved road surface. better alignnient and the safety devices installed.

1 1 1 I~.J+). the coiistructi~m of a dcviatioii tlirougli meii country between the top of Bulli Pass and Wollongong. wab untlertalien to meet military require- iiients. The nc\v roatl coninieiices at the top of the 1 ’ a s . . .incl . theii takes :in easy tlrscent to the coast. r i . j o i i i i n ~ the Prince‘s llighway just north of \\.olloii- goiig. Thc new route tlins avoids the steep grade at Hulli l’ass and also avoitls the built-up area hetween the

Struth of Bulli Pass work had been proceeding s i ~ i i ~ ~ l t ~ i ~ ~ e o ~ i s l ~ - with t1i;it t o the north. ;itid by Septetiilier. 102s. a length of 20 miles between Bulli antl Macquarie Rivulet hat1 heen reconstructed in lhuminous niacatlani. ‘l’his bvork involved some mitior tleviatiotis, the construction of several small l)ritlges a t i d tlie re-builtling c i f culverts. The replacciiirnt of tlic railway level cros4n:,. at J’allali hy iiii ovcr1)ritlge \ ~ . . I I , I > I t 5 0 etfectetl.

F(lot [If the Pass and \VolloI1gOl1g.

During the nrxt two years a further I O ~ $ miles to tlie h1iniiainurra River was reconstructed. This length inclutletl a deviation tiear Alhion Park which reduced the length of travel by 3% miles as well as eliminating steep gradients, sevcral sharp curves arid two railway level crossings. This work was completed. with a permanent pavement. hy the end of 1930. at a cost of approximately fho.ooo.

The next section o f al)out four miles to Kiama also included steep gradients. aiid surveys were made with a vicw to 01)taitiiiig more suitable grades by deviation. I t was found that the cost of deviations would be tlisproporticrnate to the 1)enelits rcsultiiig and the exist- ing route was rrtaitietl. Improvements i t i alignment antl grade were effectetl and a bituminous pavement laid. and by 1931 the reconstructioii of the Highway 1)etween Sytlney antl Kiama had I)eeti completed. a distance of 75 mileb. The total cost of thc iniprove- nients carried out lietween Macquarie liivulet antl Kiama was f I 13.890.

Between Kiama and S o w r a 27 niiles. the 1-oat1 had many sharp turns antl steep gradients Ilut preliminary surveys intlicatcd the feasiliility of imprtrvement in some cases I iy local deviation. Reconstruction of this length was coiiinieiiccd in 1932 and proceeded in stages until June, 1037. by which date the I-liglrway frnm Sytlney to Nowra. I 02 miles, had been provitletl with a Iituniiiious surf;iec. A level crossiiig was eliminated froin the Highway at ()mega. In conjunction with the roadworks. s e ~ r i i tinilwr bridges were replaccd by

reinforced concrete structure.;. locatctl :irv:iy from tlic [rrigiiial sitvs ~vlicrc ii~cessay tn ol)tain I w t t r i - alig~inient

Cuttins apprQximAtely 29 m. frpm Narooma in Mumbulla Shire,

MAIN ROADS. Vol. XI1, No. 4. ~~

Cockwhy Deviation in Clyde Shire.

\\'hilt* these \\(,rks \wrc Iieing uiitlcrtakeii I)rogrchs

I)ctwceti tlic Sli~ralliave~i River ant1 Uatetmti's Bay. ;inti liateman's Ray ; i n d the Victorian I)ortler rcs~icctiv~ly.

\v. <lh . . cl 1 . 50 Iieiiig made over the wcond and third sections

NOWRA TO BATEMAN'S BAY. Froin Nowra IWI the Shoalhaven River southwards

the I'riiice's Iiigliway performs functions which. in other parts of the State. are tlischargetl by railways. liiilirovciiiciit and rc,roii~tructir)ti of the length immedi- ately south of Nowra \vas soon put i t i hand and 1))- I 929 had I)ecii rtrnipletetl over a length of nine miles with a I)itutiiinws macatlain pavenient. Further coli- structioii continued southwartlh year by !car. with a short cessation i n the depression period. until Bate- niaii's Bap was reached in rglo. a total distance o f 75 miles. Iticlutletl i n this Irngtli is a section cc)w htructetl liv the I)elnrtiiieiit of l'ulilic \\.arks. in 1920. at Yatte Yattah tiear Milton. i n completion of plans ~irel~arr t l earlier.

For tlie greater part the cild road had been iiarrow ant l wiiitliiig with extremely poor alignnient and the fortiiaticrti width had heen only 12 ft. to 14 ft. In order to give immediate relief prior to general recom struction. it \vas tlecitlrd a t mice to wide~l the rudd

t h ~ ~ J l l g ~ l ~ l 1 1 ~ sutiiciciitly t c i cii:iI)k vehicles t o pass i n hafcty ; i . ~ . . t i i :I LO it. wide fortnatioii. \\'itlenitig work comnieiicetl in 1929. including in1pr~r\w11e11j and Iiencliing o f sharli curve.; and htrengthening of gravel surfaces.

.. I lie reconstruction work south from Nowra atlherctl to the general route of the (itd road although seldom coinciding with it. due to its tortuous alignment. Several fairly extensive deviations were. necessary. the longest being over a length ( i f (cn miles in the C(ick\vhy Ranges between Termeil and ICast I .ynne. 'l'he i i l d road in this section was one of tlie nimt wiiitling parts of tlie I'rince's Highway. It followed geticrally the line c i f

tlie ori:inal I)ush track atid wound through hteep. broken and tlensely tiiiibered country around the sides of spurs and along ridges. Two preliminary surveys were made in 1933 to determine whether it would br practicable. at a reasonable cost. to improve the exist- ing location antl. also. to ascertain wlietliFr a deviation providing first-class alignnient \vas ~rlitainable. The preliminary survey along tlie original road indicated that the existing conditions ctiultl 1)c iiiipi-overl. I)ut not suficiciitly trr meet the needi of nio~lerii trariic. A rleviation \vas therefore decided upon and construction commenced iii January. I<)$). The deviation was opnirtl to traftic i i i 1)eceml)er. 1937. Its ciinstruction invc!ved earthworlts totalling 108.500 cu.yds. and the

June, 1947 MAlN ROADS. 103 ~ _ _ - ~~

erection of six liritlges costing nearly L I I .ooo. Tlie length of the section eliminated was ,3bout I 1 % miles antl the corresponding length of the deviatioti nearly IO miles. After the iicw formation llad consolidated under traffic a bituminous surface was provided. The cost of the work. excluding the bridges antl bituminous surfacing. was L&J,WO.

Other deviations were constructed at Tomerung. Stewarts and Lunclic(~n Creeks. Myrtle tiully, Conjola, Ulladulla and between East Lynne antl Rateman's Bay.

Tlie cffect o f straightening 1)etween Nowra and Hateman's Bay was to reduce the length of travel by a lola1 of six miles. The work carried out betljreen Mowra ;mtl B~teinati 's Ray iIiclutletl the construction of t went y -1 wo concre te bridges.

BATEMAN'S BAY TO VICTORIAN BORDER, Simultaneously \\it11 ~ o r k on the more northerly

sections. mi attack was made on the prolileni o f pro- viding an improved road throughout the third section between Rateiiian's Hay ant1 the Victorian border. Some lengths of rontlway in this section were so steep. ititl it ling antl narrow that relocation was regarded as a matter for urgent attriition.

Comniencing i n 1926. tlierc wcrc nntlertaken, in order. dcviatiuns or extcnsive realignment IJetween Bega atid \Volumla 1 I 3 miles), between Shatlrach and Rraiirly Crccli 1 I mile 1 , at .\lsiips Creek ( I mile), 1ietn.een Corunna I ~ l i e antl C'eiitral Tilba ( 4 miles), iiortli (ri Rlcritiilrul;~ ( 2 milts 1 . Iret\veen Tillia Tillm ant1 Colixrgo ( I 2 niilcs). antl I)etween I3roKo River and ~ \ I S , J ~ S Creek ( 2 tiiiles). Tlie work I)ctwcen Tilln -

and Col)argo. I 2 miles. was through rough, hilly coun- try and iiiclutletl the construction of two new bridges over Couria and Sam's Creelis. Between 1926 and I 039 nearly thirty-five niilcs of completel! iiew road wrre constructed in this third section at a cost of more than faoo.ooo. approximately one-third of this i i i i i ~ i i i i t 011 works south of Bega.

T h ~ r e were also some lengths \\+err i l i i ~ ~ ~ C J ~ ~ l l l K l l t

wits undertaken to iiiterniediate stantlartls 011 existing locaiiolls. in urtler to give early relief ~iriiding more complete investigatiotl and possible relocation. or in the expectation that by stage constructic~n f u l l improve- nirnt \roultl eventually rrsult. The greater part of this work \\-as carried out as uneniployment relief. largely by hand iiietliods. to which i t \\-as well suitetl. Tlie more rliliicult cvititliiig ant1 narrow iections were iniproved i n this nianner 1)etween 1930 : t i id 1936.

Retmecn Katcinai1's Hay and Rega 1 \IO miles ) twelve niajor lridges have 1)een erected at a cost o f approxi- mately f ~o3.000. T h y include a basculc bridge at Narooma which replaced the fe r ry at that p i n t . a steel antl ctrncrctc lrritlge over the Hrogu Kiver, built in 1934 to replace the original bridge which had been swept away I J Y fl(~ot1 waters. ant1 an enicrgency single traftic lane timber Iiridge I)nilt at Lloruya i n 1 9 ~ j when a flood tleiiimyc(l tlie oltl Ill-itlge a t this site. Five major bridges costing L-.I.OOO have lleen lniilt on the Higlnva?- l r twcen Rega antl the Victoi-inn Irortlcr.

A feri-y c r i i 4ng still csists a t Rateni;uii Kay. 1 1 1 1927 the I)ep;ir~ment prwitletl. at ;I ciist c i f f2 .470 . C L

new oil-driven ferrJ- vessrl t o W I J I ~ W tlic tlicn worii- out vrssel wliirh had previously operated at that point.

a

Baternan's Bay Ferry. I

Vol. XII, No. 4. ~ _ - 104 MAIN ROADS.

Brogo River Bridge-Mumbulla Shire

I 05 ~~

June, 1947 MAIN ROADS. _ ~ _ _ ____ h r i i i g tlie past twelve niuii~lis, road traftic south-

wards rit tlie Sliualhaven River lias been at 1-ccord levels. liotli i n respect of volunie antl weight. Tlie iiuml~er of iiiotiii- ~ i r s using tlie roatl i h ahnut cqual tn 11ie highest pre-war tigur-e, 1)ut 1ie;ivy tru tlolil)letl i n nu~iilier ;ind liavc incrr;i.;ctl i l l

weight tluc to tlie gi-cater use c i i niulti-axle vehicles. Light trucks m t l ‘1iusi.s are ; I / S I ) m i w iisiiig tli in increasrtl iiiinilicrs ;ind the av~ii1;iiilt. res(m1 road ni;iinteiiance ccluil)iiietit have I~eeii taxetl to 1iec.l) liace with 11ic ncetls of the ral)itll!-esljatitliii,q trallic.

’l%e d i a p i i i , ) i i ~iagc 104 c i f traffic using tlie fcrry :it 1kiteni;iii’s Kay, shii\vs tlic increase in tratfic using the J’riiicc,’s I ligliway iiiice 1932. ‘ l h awr;igc nuniber u t vehicles 1-ccoi-tletl as luviug used tlie ferry e;ich day during J;iiiuary, 1 9 3 4 was I;O. ‘I‘r;itf;c r u e to a peal.; of almost .+w vehicles per day in J;inuary. 1939, and fv l l slightly to 30j veliicles per rhy in January. I C ) ~ O . Tlie corresl)oiitliiig figures for July were 6 j vehicles per t h y iii 1 1 j . p and 1.38 per day in 1 0 . p . In January. 1041, the average dai ly number crossing was 155. Kecorrls were disctintiiiuetl Iietweeii I C J ~ I and 1944. In January. 194j, the trallic \vas I j o per day; January. 1y4ib-250; January. 1947- 436. In Jn ly , ~ o l j , traftic was 100 per d a y ; !uly. 194f-Li35. Tlie I’riiice’h High- way passes tlirougli sonic of the most Imutiful coastal scenery of the C‘nmnionwealtli antl, oil this account. has always attracted p e a t iiuiiiliers of travellers. The tourist traliic. Imth interstate aut1 to the walering places aiitl holiday resorts trf the ;rea, has greatly exp:iniletI and iinw Iias become an iniportaiit part o f the suniiiicr and autumn traftic. Tlie diagram clearly show> the influence o f (his activity on the traHic tising the Highway.

FUTURE PROPOSALS. I t is the Department’s intention to concentrate cun-

structii~iial activity on tlie Uateman’s Bay-Bega length until this is ccmliletcrl and ~irovitletl with a Iiituiiiinous surfacr. T h v existiiig organiwtion will be increased i f oliliorliiiiity oficrs 1 1 1 ort1t.r to expedite the rate i i f

~ro,qress. Rcfei-etice liiis ;ilreatly I)eeii ii1;111c to the prolmsetl

iiew I)ritlgc‘s at U;itenian’s Bay ant1 tlie Tuross River. Secticiiis cvhich ;ire still sul~stantlartl are in many

cases under survey investigation. This work lias been f acilitatetl : . right to the Iiictorian Ijorder.

i’reliarations are ;it present 1)eiiig tiiatlc for the hitu- niiiious surfacing of sections Iietween Tilba and Col)ai-go :incl Brogo atid Alsops Creeks aiitl it may be Ixissilile to treat tliesc in the forthcoming summer.

I t is the improvemriit oi the riiatl (luring past years which lias stiiiiulatcil tlevelopnieiit. ~)articularly between Nowra aiid the l’ictoriati Iiortler, and this lias led to much-increasetl traHic and to requests for a higher 1-ate oi ruad impro~enient. The rate of progress of imlirovenient on tlie I’rince’s Highway, however, has to hc coni(1eretl in relation to tlic funds available and to the needs of all tiiaiii roads. The difficult country thrciugli \vhicli tlie Iligliwiy passes results i n high cost per mile for impr~~veiiicnt. In spitc of this, very con- s ideralk progress l i a h been made. This is well illus- tratctl Iiy tlie fact that. i n ripS. after the Highway had received m i i e initial iml)ro\~emciit. the travelling time from Kowra to Ilega was ahout twenty hours. inclutling an overnight stoil ;it Narooma. Tn-day tlic same journey takes seven hours.

hy :ieriiil lili~itogralihs which have lieen taken

Principles for Design of Non-rigid .

Pavements. e

.-4 satisfactory roatl cannot generally he niade merely by shaping the ground to the contoiir desired. The natural soil is usually too weak to resist the load- iiigs imposed by traftic. and it ruts or disintegratei. “i’avciiients“ of better material arr usually required to resist the action of t r a i k . Tlir liavemeiit spreads the \vhrcl load and reduces the intensity of loading on the uiirlci-lying soil or “su1)gratle” t o a safe value.

Many tlificrerit iiiaterials antl tlifirrent types of coti- struction are used for paverncnts. ’l‘liey may consist of a single layer. or o f two or iiiorc siniilar or tlis- siniilar layers ( o r “courses”). The various coiirses can be classified as follows :-

I . Itigid materials strong i i i tension. compression. and shear aiid used in largc slal>.q. etc.. r.g,. concrete pavcnients.

2. Similar materials in iiiotlerate sized hloclts fitted together. t’.,q., paving bricks.

* j R 126-2

3. Courses which. tliougli iisuallj- containing a numlicr o f iiitlivitlual solid pieces more or less cemented and/or iiitcrloclirtl, are. as a whole, relatively weak in tension, but strong in cnmpressioii and slicar.

l’avements constructed en:irely from courses of the tliirtl type are by far the most coninion. This class iticlutles gravel. iiiacaclarii. bitumiiioiis mixes antl all similar tion-rigid tnaterials. Bring tlekient in teiisile strength, they distriliutc and spre;id the load I)y arching action rather thair Iiy Iieam action.

l l i e top course nf ;i iion-rigid pavement is sulljected to the direct actiiiii of tlie wheel loads. Practically all

loails now iiiove on pncuinatic tyres for which iitact presstire is about equal to the air pressirre

in the tyre. About the same pressure is used in all heavy vehicle tyrrs. wlicther for truclcs. huscs, tractors, trailers or aercy)l:nies. so that for all pavements the

Vol. XII, No. 4. -

106 MAIN ROADS.

maximuni iiiteiisity of pressure aiitl stress in the top cotirse is about the same. This leads to the coil- clusion which is sup~iortetl by experience. that tor all roads. aerotlroines, etc., the recluircnients as tii quality o f the top course are the same. antl ii top courst’ suitalile t(ir nile pavement \vi11 I)e suitalile for all the others.

I he wlicrl load is spread by the tu11 course IIVC’I- i i consit1er;dily greater area uf the nrxt coursc. or ( I f the snbgratle in a single course ~ ~ ~ i v e i i i ~ i i t , tliaii the t~rigiiial contact area I)etween tyre and paveiiieiit. Intensity of pressure on and stresses in this course iirc therefore lowrr than in the tup colit-se and ii corrc~sl)ontlingly weaker material will serve. Siiiiilarly, tlie second coursc spreads the Iciatl o w r ati even greater area of the next layer ant1 so oii uiitil the suligratle is reached. \C’ith increasing depth 1)eIow the surfncc., the area of spread of load iiicreases. intensity o f ~iressure and stresses are rcducetl, antl weaker materials can be used. Conversely, other things being equal. the weaker a material the deeper iiitist it lie placed in the pave- ment or, to view it the other way round, the weaker the suligrade, or a lower course, the greater must be tlie tliickiiess of tlie overlying courses.

Again, the larger the wheel load tlie greater is the area of its colitact with the pavement for the same in- tensity of contact pressure. l f tlie size of the contact area is increased, antl the thickness of the t[qi coursc is not altered, thc pi-o1iortional increase in area of spread ou tlie next course is retlucetl. This iiieans that i f the intensity of pressure oil aiid the stresses in the second course just reached safe limits with one particular load they would lie excessive with larger loatls. Similar reasoning applies to all courses. antl to the pavemetit as a whole, and leads to the conclusion that an increase in the iliaximum wheel load requires an illcrease in the thicktiess of all pavemeiit courses ;itid of the pavement as a whole.

The ideal method of design would be to tlrterniitie, by soiiie form of test. the safe stresses ant1 the stress/straiii re1;itions for the actual subgratle antl the available pavement materials ; from these to compute the tleformatiotis ani1 stresses for tlie particular loading to be carried i n anti under tlir various practicalile pave- ment cnnstructioiis ; tlieii select the most econ~miical construction that keeps all stresses within safe liniits.

LJnfortunately, however, the computation of the stresses in noli-rigid pavements is a complex 1~rol)letii that has not yet heen satisfactorily solved. ’l‘liree ~linieiisiniial stress com~~utations are always tlitlicult. and full solutions have only bern obtained for the simple cases of uniforrn. isotropic. elastic iiiaterials

train relations. There are cotl- sitleralile errors antl uncertainties i i i applying these methnds of coniputatioii to non-rigid pavement tlesign where. in general. neither the liavenient nor the sub- grade has these properties. Moreover. the stres/strain relations for most subgrades ant1 many pvemcuts vary considerably with climges in iiioisture content. No tiictliotl has yet Iiecii developed to predict satisfactorily the actual moisture ccintetit that is likely to I v attained in service. Various enipirical o r arliitrary iiietlmds of calculatiiig the appri>ximate stresses Iiave Iieeti pro- posed because of the tlifticulties of the fu l l theoretical

,.

investigation, but these still require verification and/or checking for the full possible range of pavement roirtlitions.

I n the preseiit state of kiiowlerlgr it is iiiipossible to uiml)ute the actual stresses with any exactitude ; : i~~~ir~isitnatioiis iinly are p~issililc. L\iithin certain limits it I S , ho\vever, practicalk tci ctin~pute wi th reasonable ;icciir:icy the ratio of tlie strrsses i n similar construc- titins. 111 atltlitioii to these tliiiicultirs there is coil- sitler;il)le uncertainty :is to the magnitutlc of the stresses that can lie a 1 1 ~ ~ t l i i i non-rigid ~ ~ a ~ ~ i i i e i i t s and their sul)grarles, even i f the f u l l strcss/straiii relations are l i l l ~ i \ v l l .

RI aiiy iiivestig;itors :ire eiitlcavouritig to overcome the tlilliculties outliuetl aliuve, Imt, fur somr time to collie at any rate, design ou a stress Iiasis is scarcely prac- ticahk. Most 1ir:ictical tlcsigii folluws empirical methotls I~asetl on cotiq~:~ris(in. In these inethods tlie pavenient thicknesses for a I I ~ W work are determined from past experieuce with like pavements ;ind suligrades ; often soiiic selcctetl tests are used as ;I nunicrical Iiasis of comparison.

Many different kinds of soil are found as subgrades antl there is a wide variaticin in , the materials used for non-rigid pavements. Local contlitions atid Imtliiig to lie carried also vary. For practical design. it is usual tu tiiake simplifying assumptions tu Iring the 11roblem of design within reasonal~le bounds. It has been found by experience that certain assumptions are generally satisfactory.

Firstly, there is the prolileni of nioisture content. l lost soils antl niaiiy p:ivement materials are susceptible t u water and their strengtli varies greatly witli changes in nioisture c~intent . The moisture content of any por- tion of a pavemetit or suligratle varies with the materials. the cliiiiatc. the drainage jl)otli surface atid S I I I I S ~ I ~ I ) , and tlie e lse with which evaliorati~~n to the atniospliere talics 1)lace. \7ariations will n;itur;illy occur with cliiiiatic vagaries a i i d an!’ given portioii will, with tiiiic, pass tlirougli a11 mrlisture c o n t e ~ t s witliin s o ~ ~ i e ~iarticular raiige. ’J‘lie n~imeric:il limits o f this raiigc uiitlcr any given coiitlitims calulot be lwetlictetl froiii tlie litiowlctlge yet :i\~ailal)le. I N I mattrr i v l ~ n t tests are c~lntluctetl.

The tiornial o1)jective i n ro:ctl drainage is to retiio\rc surface water rapidly ;und to kccp o r lower the free groutid water surface well lielow subgratle level. I t is usually impracticable so to l o w r the grou~id water that :he subgrade atid ~)avement a re above tlie ca1)illary fringe. This cotidition may lie called “nol-mal atid satisfactory drainage.” LWiere it applics the sulrgrade m t l li:ivement are exposed t o capillary water but not t o free ground water. I<xperience seetiis tn indicate that. where a pavetiient iiiaterial or suhgrarle is protected from frez evaporation and the tlraiuage is normal and satisfactory. the worst iiioisture i‘oiiteilt. antl the cor- responding lowest strength whicli it attains in service, is sulijcct to very little vari;ition. This c~intlitioti docs not hold i f the frec ground wafer level rises at any time aliove. or ~iossil~ly very near, tlie ni:iteri:il in ques- t i o i l , or i f the free groutitl wciier levcl is very far 1)elon~ the pavement.

June, 1947 MAIN ROADS. I07 -~ ~

Conditions of Iirotectioii from free evaporation nor- mally apply to all materials below the “Black t o p ” of Iiituniitious surfaced roads. atid. also to tlie subgrades and Iowei- coui-scs trf un.iurf;icetl roads becausc surface cuurses hinder evaporation. In these circumstances such changes in iiioistiu-e contcnt as occur will prin- c ip l ly lie due to ground water effects. ’fo offset such efiects drainage slioul(l lie ;itljustetl to climate and topography i n such ;i w i y as t o liceli the free grouiitl \vater levcl l )Chl\r tlre .sullgr:ltle.

On the other Iiaiitl. (rnly i t i specially fwouretl places is it pnssil)lc t o kcel) capillary moisture away frotn paveinents. ereti i n the driest cliiiiatcs. For practi- cal tlehigii it is therefore generally assumetl, even if the assumption is not f(1riiia1ly stated. tliat under coil-. tlitioiis of norni:tl a i i t l satisfactory drainage. the limit,< of moisture content am1 strength of a given material arc subject to little variation ; only in extreme cases is any adjustment for rninfall, etc., necesiary or even t1esiral)lc. This iiie;iiis that the worst service moisture content, and the ctirrcspontling strength, can be re- gartlerl as an inherent property of the material. ‘This I S automatically takeii into account in the comparison method of design although not actually determined. In some inethods u f clesign of pavement thicltness this same assumption is expressed differently by saying that undcr tlie p;irticular conditions, the strength of paverneiit required over a given suligrade is practically const;int for a constant loatling.

The upper courses of unsurfaced pavements are inore affected by clitiiatic variations than the preceding cases. Even here, however, the tratiic tiorinally has to lie carried both wlicti the pavement is saturated and whcii it is dried out by the sun. Variations in the re- quirements with climate are thcrefore not considerable.

Some climates with rigorous winters aiitl frozen ground followed by spring thaw are far more severe on pavements and suligi-arles than ordinary wet weather, I)ut in New South \\‘ales these conditions only occur i n a few small isolated areas. The ordiirary night frost, which does not penetrate to any depth. is of no imporlance.

Sccoiidl!. there is the question of compaction. The strength of all soils antl pavcmeiit inaterials varies grcatly with their degree of compaction. There are two schools of thought on this subject. The majority view, adopted hy the lkpartment, is that i f subgrades and paveincuts are i)i-operly constructed aiitl compacted and then subjected to ti-aftic for a sufficient pcriod, the compaction will reach n stable value ; and. i f this com- paction is not achieved Iiy the time the “black top” is constructed. subsequent rompaction and settlement are inevitable. \Vith this assunq)tioti the equilibrium coni- paction is also regartled as an inherent property of the niaterial that is autotiiatically allowed for in the coni- parison method of design ; 011 the other hand, it is essential to verify thc conipaction both of the pave- ment and of the sulgratle Iirior to constructing the Iiituniinous surface.

1 he alternative viewpoint is that suligratles antl lower courses are stable over a liniitetl range of com- ~raction : design is therefore based on tests contluctetl at the actual or predicted state of coinpaction.

, .

Thirdly, there is the question of stress distribution and thicknesses required in multi-layer construction. The followiiig rules are generally used :-

Case I . Single course pavement of material A on subgrade B.

( U ) Material :I has to bc of certain minimum quality, regardless of its thickness and the nature of niaterial B.

( h ) Thicknexs of layer X required d e p e d s mi nature of Iioth X and R antl on loatling.

( c ) For two different pavement materials ( X I antl LIZ say) the ratio of thickiicss required of X I to that of Az i s the same whatever the loatling atid the nature of material E ; i.e., the relative value of the two materi:ils as load tlistrihuting agents is constant.

Case 2 . Multi-course pavements-say. surface course of A, Iiasecourse of B, on suhgratle C. (The extensions for a greater number of courses arc obvious).

((I.) As for casc I ( ( 1 ) (see preceding paragraph). ( b ) As for case ~ ( b ) (disregarding layer C ) pro-

vided the coinhitied thicktiess of A and B is suilicient to prevent overstressing of C.

( c ) As for case I [ c ) for tlie relative thickness of AI antl A2 subject to same conditions re layer C.

( d ) Similar rulcs hold for tlie coiiibined thickness of layers A and B. They arc most simply ex- pressed hy saying that the miiiimuni value of (pa + q l i ) is determined by the nature of material C and the loading only. where “p” and “9” are co-efficieiits tlepentling on tlir nature of the materials in the layers .A and B respectively and “a” and “b” their thickness.

These rules have an o1)vious logical basis and h a w been found tu give reasonable reliable results in actual practice. They cati be restated i i i the following simple general form :-

( a ) Each lower course arid the subgrade must have a certain thickness of material aliove itself which will vary with tlie nature of tlie upper courses, but cati be reduced to a single measure which nwy be called the ”effective cover” (usually expressed in inches of some standard material, e.g., gravel). The “effec- tlve cover” required Over any givcii material depends only on its o\vii nature and the loading.

( b ) The “effective cover“ over any course is com- puted by inultiplying the thickness of each overlaying course by a factor, which depends only on the nature of the particular course, and adding the products.

Before discussing practical design methods, it is desirable to consider, in a general way, the nature. and properties of thc iilaterials in the pavement and subgrade.

( I ) There are the materials capable of resisting the stresses imposed at the surface of the pavement, Obviously tliesc are safe in theniselves for use in any

Vol. XII, No. 4. ~ ~ _ _ _ _ _ ~ - - MAIN ROADS. ~-~

I 08 - ~ ~~

portion or course. They include constructions of stone and/or Iiitumen, e.g. , macadam, hituminous penetra- tion, suita1)le I)ituniinous mixes, etc. They also include certain natural soils depending for thelr strength on the ronil)inetl friction and cohesion of :i well-gradcd inistiire ol mineral pr t ic les froni ciiarsc sand to tine clay. 'l'hese are known ;is "12oad (;ravel" or "Gravel" iii this country i f they contain a consitlerahle I)ropor- tion of stone cuw .er than sand, or as "Sand Chy,"

Also. there :ire artiticial mixtures of natural inaterials ; graded mix- tnrcs niade Iiy crushing hart1 rocks antl conibining the pro(lucts o f crushing i n suitable proportions; a n t l graded materials produced by breaking up shales, etc.. on the road 1)y coiiipaction, weather, antl trafic. .All o t these suhstitutes have tlie grading and properties of rcratl gravel.

These gratletl inaterials neetl not I)e considered further, iior neetl the bituminous and stonc construc- tions knowi to be adequate for the more lightly stressed base courses though too weak for siirfacc courses.

( 2 ) Then there are the soils ( a i d second grade gravels) that arc not of sufficient strength for surface coursc. These may depart from tlic requirements for surface coursc material i n varying degrees and in many ways. Tlie most iiiiportant practical cases are, in order of ircquency antl ituportance :-

( ( I ) Ltaterials with excess "tine" sizes of which the extreme case is p r e clay. These are the iioriiial plastic and cohesive soils.

( 6 ) Matcrials with deficient "tine" sizes of which tlie extreme case is pure sand. These are the noli-plastic and sand soils.

(0 Materials with much peaty organic matter or mica which may be associated with any grad- ing of the mineral portion of the soil.

( 3 ) A l l types of transition soil may occur, also soils with ninusual types of grading not inclutletl i n the above groups. Many soils also contain a proportion of aggregate coarscr than sand. not considered iii thc ahove grouping, which givcs some iniprnvement in their strength. The range of properties of subgrades and hwer coarse niatcrials can. however. he suficiently dcn~r~nstratrd with the extreme cases o l tlic ahove three types.

Tlie mechanical strength of a clay varics enormously with its moisture content. Wlieti dry it may approach the strength and Iiarc1ne.ss of stonc. but its strength decreases rapidly with increase in water content. A t the moisture contents usilally attained in subgrades it is sott antl plastic. In this condition it is practically incom~~ressible and failures occur by plastic flow or shear. In its normal soft state a clay tloes not exhibit a linear strcss/strain relatiotisl?ip. The strcss/strain curve is concave tu thc strain axis (i.?,, strain increases inore rapidly than first power of stress) antl hecotnes almost parallel therrto hefore rupture occurs. The strain is often also a function o f time. increasing with time at constant stress, and is largely permanent. i.r.. the original shape is not rcgainerl on removal of stress. Anothcr important point is that the strrngth of clay is titie principally to cohesion. and its internal friction

"Salltly I.~lanl" (11. ' 1,oani" i f they tltr not.

is low. This means that its resistance to shcar stress is but little altered by compression stresses acting simul- taneously. l n clay suligratlea untler flexilile pavements, compression stresses are not Iiigh. antl tlic shear resis- tznce of the clay is practically indel)endetit o f the cornpressioii strcss that is ;ilso iictiiig.

'rile mcchaiiical properties o f s;tntl arc \-er!. different. Sand is practically nnaffccted I)y water, Imt its strength depends consitlerably on tlie degree o f ci~nip~rctirin. In its normal compacted state i n snhgratles. sand is practically inconq)ressiblr, and shear strains are negligible, antl 1)rol)alrly have a linear relation with stress, up IO p i n t of failure. liailure is sudden ant1 complete. large movements occurring a b soon as the shear stress excceds a certain value. Since the resis- tance is due entirely to friction, cohesion being absent in sand, the ahcar strength tle~iends on the natnre of the loading a i d the degree of coiitinement of tlie sand. Sand has zero strength in shear i f no coinpression strcss is acting simultaneously. \Yhere there arc compression stresses, tlic limiting shear stress on any plane is tlie conipression stress on that plane multiplied by a constant called the coellicieiit of internal friction. This coefficient tlepends on the nature of the sand.

A peaty soil differs again in that at iiornial nioisture contents it is coiiipre.ssihle ant1 deformations from this causc arc more important than the shear deforinations. 'l'he compression is largely elastic Lor short time load- ing. the original form being more or less regained or! renioval of load. The total dcformatioii of a peaty soil is. in general, niuch larger for a giveii loading than tlie other types.

Ib'itli these major differences in I)ehaviour under stress, it is at least tloubtful that itlctitical treatment will apply to design on all types of soil. Some changes or variations are to be expected between different soil types. They may Ire arranged. however. by adjustments to testing procec!ore or. wlicre graphs arc used, in the plotting of design curves. although in this case the atljustiiients may not be apparent.

As l)rcviously stated, tlie practical niethods in general use ;ire em1)irical and are lraactl on coni- p r i sons with past experience. Some are based on various stress/strain iiieasurciiieiits an(l may appear at first sight to he related to the direct attack by stress coinputation. T n practice these measurements are, however, used as intlicatiotis of relative quality only, and the actual design is hased on past experience and on the comparison of tcit fignres with tlrose o l similar tests on soils which have given known service and perf orniance.

Generally the methods assume a staiidartl loading, iii which cise adjustments for other loads can be made on the lines set out below, but in sonic incthnds this extension is included in the formal statement of the nlclllod.

If tlie pavement required on a given soil is known from past exl>cricncc. and i f tlic soil r m new work can he positively identified with tlie known soil. nothing furthcr is required. This method is of great value in limited areas if practisecl only by those with detailed local knowledge antl experience : it is of especial value

MAIN ROADS. 109 June, 1947 --

in towns Lind villages where roadworks may be COII- centrated iii a small area. I t is unsound, however. to apply this method over wider fields or after cursory examination oiily. Positive identification is usually

I h e niet1iotl.s best suited to general works are based on identification or comparison tests. All the reliable methods 1iai.e Iieen estal~lislictl 11y :-

( ( I j Determining the performance and service of it variety of inaterials by experience.

(KI Su1)jccting each of these materials to a cer- tain test or series of tests.

( ( 1 Comparing the test tigurei with tlic s e r v i e rccurtl and estalJlishing a iiiore or less coli- sistcnt c(J~lT~ati(i11.

( t i 1 Settiiig test limits f(ir s u r f x e co~irsc inaterial-. Iiqiiiig a ncimcrical or graliliical

nietliotl foi- cniii~iiiting the necessary covci- over base courses, suligrades. etc.. from the test tigrircs.

The value and scope of any method depentls on the consistency (if the correlation and the range of materials for which the correlation has heen estab- lished. I t is clear from what precedes that a particular method may be reliable for one series of soil tJ-pcs and fail utterly in others.

Sonic iiicthri(ls are based oii stress antl/cir strain nieasurements of ;I specimen. others are based oii tests liming no direct rclatioti to stress. IVIiile stress type tests i:aturally make an imiiietliate appeal to those utl- ;t\wre o f tlic real naturc o l the ~iriil)leni in hand. there is no sountl reason to expect :iny superiority for either type. I t X ~ P I I I S I)c well c.st;ililislierl that 1,otIi tyl~ei give satisfactory means of coinparison with liiiowii siiils aiitl this is the itrtuitl olijectivc of tlie tests. 111 practical work it has IJeen for in i l , I)otli by the I)el)art- nient ant1 by others. that major eri-(irs murc conimonly ;\rise from imliriiper suiilJiiig or from the use of materials differing froin tliose sampled and testid, rather tliaii from the tcstiiig aiid the iiiter1)retatioii o f the test tigures.

The n i r i h t widely usetl systeni is that piit forward I i y the United States of :\nicrica I’ublic Roads ..\(I- ininisti-ation ( see I’u1)Iic l<nads. 1942). It is basctl (111 a iiuiiilier of simple tests. mitie of which involves >tress-strain measurements. Ijy these tests. tlie soil iz classified i t i t o imc o f ciglit gron1x Oiily oiie of these gr(iiips i ? suitalile fur top course. for each of the others the rangc of cover requirctl for standard I(iat1ing i5

given. I<y com!)aring actual test figures with the limiting values at the proup bouiitlaries tlie thickness required over any pat-ticular soil is interptrlatetl. A - most all soils caii be treated l)y this system. but there are a few which cannot lie cl;isritietl in the eight groups iirovitletl and the systciii tliies not cover these materials.

Otlirrs use what might lie calletl “point score” systems based on simil;ti- tests. I lerc each test figure is converted by smie suitalJle arithmetical treatment into a numerical measure of quality or number of “1)oints.” Thc sniii or avcmge of the points for all

cult and appearances are often misleading. , .

tests is a measure of the thicktless of effective covcr required. In such systems the range of soils to urhicli ttiey apply depends on the nature antl number oi llic tests taken into account. One or two tests may suKice for a single group of soils. but would fail for other groups. I t is i rn~~r~iba l~ lc that the same tests alltl point score foriiiula would apply universally. Within its acripe a well selected formula of this type is reliable.

For some years the 1)cpartment of Main Roads. New South \\:ales has based its testing and design cin the I’uhlic Roads r\tlniiiiistration tests ancl methods of interpretation. I3q)erience has indicatetl that some inotlifications ai-c tlrsiritlilc fnr conditions existing iii New S(iut1i \Vales. The Ilepartnient has therefore carried out consitleralde rcscarcli a~ i t l anticipates puli- lishing tlic coiirlusions re;iched i n future issues of

The Iiest ktitiivn iiictliotl based on it stress/strain type of test. is tlie Californian Bearing Ratio. generally ablxeviatetl to “C.13.K.” This tnethorl as originally developed by the Califoriiian Highway Department consisted of :-

( t i I Compacting the sitiiiple under stantlard condi- tioiis in the lalxi~-atory a i d then exposing it to water under standard contlitioiis.

( h ) Siilijectiiig i t t u ;i standard strain antl deter- mining tlie stre.;\ ( reported as n perceiitage ratio ( i f the stress tlevelopetl Iiy a standard material under tlie same conditions).

( I ‘ ) i\ssessiii;: the quxlity by coni1~;iring this ratio with a gralh ihtainetl from similar tests mi soils of kt iowi i ~ierffirmance antl quality. T h i s graph gives tlie effective cover recpirrtl for stantlard lmcliiigs,

I l i ih metlioil 1,eai-s no relation to thc stress cc1111- I)utaticin nietliotl antl is just as empirical :is the Fuhlic Roads :\tliiiinisti-ati~in o r point ire nietliorls, Fur tlie range of soils ciiveretl Iiy the C.B.R. test in its original form. i.c.. ft-om top co~ii-s(’ materials to plastic clays with all iiiternictliate types. all tlirec niethotls appear to I)e reliable and there seems little to choose between them oii that grountl. Tlic I’ulilic Rmtls .Atliiiinistra- tion aiitl “point sc(1re” systems involve less work in sampling and testing than the C.B.R. test.

The Linitetl States . \ rmy adopted the Californiaii Bearing Ratio metho(1 for wai- purposes aiitl has puli-

iiiucli iiiii~riiiati~in oi l its application to actual Three extensirins of the nietliotl have been

A. T o greater loads. This has a sound basis (see helow ) .

R. To other typcs of soils. \\‘hikt this was neces- sary for war-time purposes there are uncer- tainties i n this estcnsiuu rcquiring examina- tion. Organic and clay soils proliably, hut not certainly. will have a similar relation between C.B.K. and cover ieqiiiretl. but it is quite probable that sands will not.

.‘I/ (1 ; I I 0 f l ti$.

~.

applied. iianirly :-

I10 MAIN ROADS. - . . ~

-~ ~

C:. To cover different initial compactions. \~’hilst this extension was justifiable for urgent war- tiiiie ivorks, it is not generally aceptable for permanent works. [See discussion above on compact ion. )

’l’he C.U.K. test consists of forcing a flat-ended I)luliger into the 1irep;ired sample. Similar methods lii~ve been developed from penetration tests with a conical plunger, and from the various lahoratory tests for tletermining the shear-stress/shear-strain relations.

.\s statctl above. all the practical methods are based on soiiie stantlard loading. normally highway loaditig. In sonic cases, however. as in aerodrome design it is necessary to extend the nwthotls to heavier loads.

:\I1 soils tlcpcnd for their resistance to shcar on colirsion anti friction. Tllc former is tlic major factor in clay antl tlic latter the sole factor in sand. If iric- tioil is negligi1)le. ;is in clay. tlic permissible shear stress in :i sul)gi-atlr or lower coursc is almost inclcpcntlcnt of the conipressicin for met with in pavement sub- grades. antl the permiss e shear stress is riot affected Iiy the weight of the overlying pavement. By the principle of similarity (irrespective of actual mode of stress tlistriliutiot1) it follows that. for the sane in- tensity of tyre pressure :intl tlie same Ixivcnicnt and sul)gratlc ni;itcriiils. the stresses arising from the vvlicel loading will Iic q n ; i l i n all cases whcrc all linear tlimensions :ire in the same ratio. i.c.. i f the tlliclaess r r f p;tventeiit is Iirolrortional t u the linear tlimensions of tlie contact area of the wliecl load. This tneans tllat for clays. etc.. tlic Iiavemeitt thicliness necessary varies very nearly ;is the linear dimensinn of the contact area or ;is tlie sqii;irc root o f the whcel loatl.

Similar consitlcrations apply ttr the case of cntil- Iircssililc soils :uld lead tu the conclusiciti that a sinlilar relation is approxiniately true for peaty soils. etc., where cotnl)ressioii unclcr the \vheel load is thc niain tleforniation.

1n sands. where friction is high a i d culiesirin is ncgligilile. cotitlitioiis are quite different Imausc th r permissilile shear stress is in direct propnrtion tu the conqircssion stresses also acting. and increases with increabing wciglit of overlying pavement. By the sanic principle of sitnilarity. i f the pavement thickne linear tlimrnsions of thc contact area. antl the intensity of contact pressure are all increased i n the same pro- pnrtion. then Imth the shear and the compression strcsses arc cvcrywliere increased in that proportioti. This nic:tns that with this rcstriction on intensity of pressure. conditions are comparable in the two cases, or tlic carryitiq capacity of a sand sul)gratlc is increased ;is tlie culw of tlic pavement thickness (or thickness as the ciilw root of the wheel load). In actual loadinqs the inteiisity o l iircssurc docs not iticrcase with heavier loads. The safe loadinc therefore increases rather ninrc rapitlly tliaii the culre of the pavement thickness. The error introduced Iiy assunling the ahove “law” is sniall atid on the conservativc side for large loads ; it may. thrrcfore. be safcly ticplcc(cr1.

Tliickness c;in i1ierefnt.c Iir cstimatcd for lareer than stantlard loads. assuming. pneumatic tyres. as follows :-

io ) For clay and high organic soils. thickness should be increased iii proportion to thc square

Vol. XII. NO. 4.

root of the ratio of the tc:,tal \ v I 1 ( ~ 1 lo;itl to the standard load. (Note---L)ual tyrcs to be counted as a single wheel. ;uid individual wlieels tu Ire sufticiently +,paced to avoid over- lap of Io;itIetI areas of sulqp.tlc. etc.).

( 0 ) For interniediate types from clays and peats to niaterials suitable for top courscs the same rule can be applied, r\s top course materials arc apprnachetl, friction 1)cconies important as well as eohebion. This rule is then rather cotiser\:ative for the larger l ( i ;~~ l s . l’avement thicknesses are. hriwcver. not mtluly great in such cases and. \vhilc sonw adjustment could he matlc. i t is rarely of mucl1 imlicirtance.

( c ) For sands tlie increasc iu thicLtiess ilioultl lie in prq)ortirrii to the c111)e root of the ratio of the wheel load to the si:uirlartl lnatl. This s;niie rule can I)c :ipl)lic(l t o all soils Iietween sand antl niaterials suit;llile for top cowscs. Cnliesiriii I,ccnmrs of importance as the latter are appr~i:iclietl antl the culie l a w is tint then strictly true. I n stlcli c.ises. Ilowevcr, thick- nesses are so sniall that it re;isiin:ililc apprnxi- iiiatirrn is all that is ircqi~iired.

Oftcn the question of frcqucncy of rcpciitioii o f loa(1 is raised. ()Iiviorisly. ;is ;I s:i1~1 sul)gr;itle can fail cotii- pletely iunder ;I citiglr lo;itling. thc frequency is c i f 1 1 0 iinport;ince i n tliis caw ; i n t i the iii:ixiniinn lo;ul governs

of an oicr1o;itl coiisir1eral)Ir nncc (h ie p~issiiiility is thc Iravrnicnt will occur. freqiiency afirctiiig the tinic Ini t not thc fact o f failut-c. .-\ltcrnativrly. untlcr inornial conditions of iiiainteilance a i l c l rrn al. frrrluctic~- ni;i). l)r c i f some iniliortancc. It is v tliliicult to scliaratc tlie cffcct ( i f frerluency from that of \\-lied Io:ul i n srutlics of performance. For nornlal freqncncies tile (IiHercnces. i f any. tlne to freqwiicy arc ~ n i d l . The I)cl):irtment. pending aiailaliility of forther d:lt:L, til;ih-cs n o ;idjust- ment on main roads for frequency of 1ii:icIitlg. For tctnporary or little tisetl roads it is pr~ilr:iIrly ~icrniissil)le to reduce the thickness on clays. etc.. Iicc:iuw of the tlrcreasetl freqnency of loading.

From the lirief tlescriptirm tha t Ilas I W C I I giwn to tlic nirthotls I n which non-rigid IxLvenwnts :trc now designed. it will I)e sccii that thcrp are still many 1111- answered questions. Drspite the intcitsive rcwarch that has been imtlertakeii i n the past ;ind is still lira- ceding. much investigntioti 1i;i.i yct t o I w tlniie llcfot-e tlie fun(laniental (lata is coinpietc. a i i ( 1 I)efrire the inetliutls of t1csiC.n trf tion-rigid navcnrcnts can lie regarded as entirely satisfactory. I his 1irihlm1 is o w o i the mnst tlifficnlt in road engincc.ring:. i t does such a larqe I)rnportinn n f all ro;i(i solution is of tlie greatcst imlirirtancc in iiatiotinl economy. 1)articularly in Auatr;ilia \vhcrr. tr;tffic coli- ditions ant1 available funds call for a very long mileage of “low-cost” pavement constrnct.ion.

June, 1947 MAIN ROADS. 1 1 1 ~- ~~

Canberra Aerodrome. Construction of Runways.

e \\'orli recently completed hy the r)epartmctit for

the Cummonwealtli Government on the aerodrome at Canberra, Australiati Capital Territory, cornprixes tlic coiistruction of two rnnways, one f.om ft. and the other 5,450 ft. in length. al)rrut 2% miles of taxiways, a central hartlstantling area adjacent to the previously existing Iiangars. and estensivc drainage works.

1 he aerodrome. situated four miles east of Canl)erra, was licensed as an "all-over" field ( i . ~ . . witliout tlelinetl runways) and had k e n in use for some years, the ground surface in its natural state Iicing used as '1

landing field for aircraft. The natural soil. which varies from sandy loam of good bearing value but somewhat friable nature to a material bordering on clay, sustained the limited aircraft trafiic urider normal weather conditions. After heavy rain, however, soiiie areas of the field softened and were cut up to such an

~.

extent that aircraft wcrc bogged tlo\vn and, on occa- sions, it became necessary to close the aerodrome until contliti~ins improved. Ti1 dry weathcr. and particularly in areas where aircraft stood with tlieir motors ruii- ning. the slipstream f r t m propellers lifted the frialile surface soil so that the suriace was rendered extreiuely iiiie~eii and serious (lust trouljles \Vere created.

1Vitii the increase o f air traftic in recent years it l iecam apparent that lmpai-cd runways were essential to the successful operation of the aerodrome in all \veatIiei-. and it was tlecitlrtl that the runways shoultl be laid cint and designed so as to l)e suitalile for use by nii~tlerii heavy aircraft.

The work carried out by the 1)epartment of Main Roads. New South \\-ales. has heen under the overall control of the Comnion\vealth Department of Works arid 14ousitig ; (lie latter lkpart t i~cnt having providecl

CANBERRA AERODROME A.C.1: GENERAL PLAN

Vol. XII. No. 4. ~~

MAIN ROADS. -

112

- . . - . - ,

1 . General view of Canberra Aerodrome from Mt. Russell Lookout. 2. Gravel loading at Sutton-road Pit. 3. Carryall Scoop spreading fill in runway. 4. Sand for stabilising in spaced heaps on gravel base course, 5. Motor Graders mixing sand and gravel in pavement.

113 -

June, 1947 MAIN ROADS. -~ ~

the design, specification a i d nraterials to be used. Hrief particulars of salient points of the design are:-

llaxiniuiii loneitutliual erade on rutiwavs, L % .

Ftanding. 14 in. Tlcaring of 7.0oo ft. ruilway. 170’. ! Ikaritig of 3.4.jo f t . rutnvay. I L O ’ .

.l’hroughout thih :article each runway is referred to in tri-iiih o f it,. licnriiig.

1 hcrc I V C ~ I - C slight untlulatim~ in the surlace of the aerotlrcinle i t i its natural state. These were not seriously tletrinient;il to the IISC ( i f the aerodrritiic for the landing of light aircraft. l i u t it was necessary to carry out n consitleralile a iount of cartIi\vorh to bring the runways into coli furiiillt y wit11 ilcsign stantlards for motlern heavy aircraft. The maximum cut for tlie construction of the runwayfi was 1.43 f t . and the maximum fill 3.4 ft. The construction o f flight strips (i.r.. the areas adjacent to rtlgrs of i - i i n w x y ~ ) and thc iicccssary levrlling of the 1i;irtlstantling ;LI-W :mtl forming of tasiwnys also iiivolvetl cotisitleralilc cartlirvorlis. It ivill he apprcci- atctl that, wlicre riuiwiys are cscavated lielow natura! s u r f x e level or I i u i l t up on filling, it is necessary to gratlc the flight strilis ul) or t l r i w ~ i uver ;i witltli fro111 tlic etlge o f tlie riin\vay to n:itural surface. The niasi- mi1111 witlth of flight strip at (.anIiivn .\erci(Ironw is .;l.j f t . . :incl tlie ;iver:igc iritltli is : i~i~i~-~isii i i : t tel~~ 230 ft. oil eitlicr side of rtun\rays.

Qiiaiitities of tlic principal items of tllc work :ire :--- ICartIiworks, 107.000 L I ~ . ~ ( I S . 1’aremcnt-llitin~r:iys. tcisiways and liartlstatitlillg.

(~‘nlile tlucts-4 i i i . dix. concrete pipes. h.4t$, lin. ft. l’ipc drains. 13,040 hi. ft . (‘otic-rt-tc (lraiiis-.grated. 6.700 l i t i . f t . ( )pcii (Imiiis. o.,j(m l in. f t .

I ~.

:

31 I .OK) sq. ! (IS.

Siirface \ratel- is collected i n a systcnl o l opc~i drains lca<liiig to sump iiileti ii-mi wlaich it is carried in niider- :,.roiuitl pipc tlraiiis to a11 a t l j ; ~ e n t watercourse. T!le pip(> tli-;iins wi-y f i n i i i i 0 in. trt qS in. (liaincter.

1’;iwiiiciit grxvc.1 \v;is taken irom detrital deposits iiciir t l i r (_)ueanlie!.;iil~~c;uttc,n roail, ; i l ) i i u t 3 miles froin (,)ue;iiilicyata aiicl 7 rides from tlie acrotlronie. Thi5 material is altered shale nith a proportion of quartzite atid some quartz fragiiirnts in a matrix (if loamy sciil. I t w:is usc(l in its n;iturd state for Iiase course o11 the 120’ roiiway. on the 170” runway for 1.303 f t . at the ~oiitherti end, nntl O I I z: slinrt taxiway Icarling to the civil airport haiigars.

I t \va\ fomi:l t I i ; i t thc gravrl x i > (1el;ciriit in intrr- nietliatc grain siz ;ind. for all sulisequent p ~ v e m e n t iv(irk, i t \vas stab std Iiy the atltlitiriii of coarse sand

from the Iietl of the Molonglo Kivcr a t a miles from the aerotlrome. =\t first, the

1 . Six-disc Plough in operation mixing dampened pavement materials.

2. Sheepsfoot Rollers consolidating sand-gravel.

3. Motor Graders engaged in final grading prior tq pweepinj of the finished pavement

MAIN ROADS. Vol. XII, No. 4. I I4

Excavation made by Carryall Scoops f o r 36-inch concrete pipe drain.

I .

Trench excavated by Barber-Greene dil cher for concrete pipe drnin.

1111 the sul)grade i i i IicalJ>. :is tippctl froiii tlic 111rric*, t l ~ c 1ocrbe quantity being c;ilculirtc~rl :is sullicictit t o I)rovitlc half the coiirsc t1iickiies.s o f the liaveiiieiit \ \di~w toll- solidatetl. The Iiea1)s \vcw tlien s~irc:d Iiy Iie;ivy tluty motor graders until i i i i ci-cii Iiiiisc >tii-f:icc \vas ~)litaiiied. I Iic hand \vas similarly tluiiilicd ;ind spre:it\ oii the

gravel surf;icc. and tlic. gr;ivrl :iiitl s i n ( l wcrc misetl in the (11-y. Iiy tyiiiiig a l i i 1 Iilatling with t1ic g ~ ~ l c r s .

Satisfactoi-y iiiixiiig \vas olitaiiietl. iiiitlei- iiormal coiiditioii~. 1 ) ~ oiie comlilctc tyiiiiq follii\vcd I)y hlad- iiig the pavemelit iiiatcarial i i i t r i windrows with two "passes" of the motor gr;itler. 0 1 1 the l i n t "pass" tlie niatcrial was bladed into a wries of wiiidrons all on the same side of each strip of pavcment m:itcrial I)eing mixed. During the secotitl "pass" tlie material in tlic wiiidrmvs. made during tlic first "pass." \vas turned over and across. each strip Iwing worked to form a \\~intlrom oil the opposite side of cach strip. Following these two mixing "passes" with the grader. the niixrtl material was slwsxl evriily ovt'r tlie area.

\\'ater was atltletl and inixrtl tliri)u:.h the coiirse until optimum moisture contetit \vas olitained. The mixing was carried out b y disc harrows. the tiut~iber of passes for effective mixing o f the water throughout the coui-se I)citig oiic or two. according to conditions.

1 lie optimum iiioistiirc content \viis first tlctertiiiiied in the lalmratory a i d samples of thr p a ~ r i i i w t tiiatcrial at optimum moisture content \vwc cs:itiiiiirtl l)y all rrspoiisible for the work. ( )I)tiniiiiii inciisturc in the field was then judged l iy coiiip:iring tlic. a1il)carance atid texture of samples talieti frriiii the I)rqiaretl pave- ment with that of the I)reliiiiiiiary demonstration

. .

I .

1 I5 ~~ ~ .

June, 1947 MAIN ROADS. ~~

samples. Succcssful judgniciit requires experience and training; as a check on the actual moisture content periodical laboratory tests wcrc also conducted. Thc laboratory checks are necessary because a field ofticer, eveti i f capahle of currectly judging the moisture con- tent at coniniencenient of the work, may find that, as tlie work proceeds, his idea of tlic moisture content of field samples sliows a gradually increasing divergence from the moisture content of tlic preliminat-y lahora- tory samples.

Having ohtained optimum moisture content i n the gravcl-sand mixture. sheepsfout rollers were inimedi- ately applied and rolling continued until the rollers “malkctl out’’ of the material. Consolidation was coim pletetl hy rolling with pneumatic-tyred and smooth iron- tyrctl 1-ollers concurrcntly with :I filial trimming off with the graders.

Frequent tests of the degree of compaction actually obtained wcre coniinctetl (luring the work. Samples of the conipacted pavement were taken and the dry weight per cnliic foot theii tletcrniincd as a percentage of the dry weight of the material as mixed in the lalioratory and cnnipactcd by the Modified Proctor Density Test (.4.;\.S,H.O, Method No. Tq‘) j . The criterion is that the tlegrcc of coiiil)actioti developed should I)e not less tlian 95%. of tlie lalioratory conipaction. The compac- tion actu;rlly n1)taiiied averaged cyq:% and 97.9% on sn1Jgr:itle aiitl Iravenivnt respectively tlirnughoril the work.

In :ill there were :ipliroxiniatcly I .+o lalroratory tests m:ide on the \voi-k. comprising conilxiction tests. niec1i;inical analysis m i l suiitlry rrtlicr tests o f tlie materials used. A tieltl lahoratory was estalilishetl at tlic aerotlronic antl (lie tests were carried out by an engineer trained in this work.

Ih-y compressirrn tcsts \vei-e not part of tlic routiiie testing Imt were introtlucetl ;it one stage to assist in determining tlie relative merits of the 60% -40% santl- g r a \ d mixture a i d thc 50%,-509; mixture. I t was found that the latter mixture (that generally adirptetl) developed a strength when tested in 3-inch cu lm of S89 111s. per. sq. in. as coniliarc(1 with 640 11)s. per sq. in. for the 60:6-40% mixture.

Cnrrvall Scoop unit at work on excavation of Drainaje trench.

Barber-Creene ditcher in operation

I’rilicipal itcins o C plant eniployetl on ihe work

I O Improved I )7 track-type tractors. 3 witli hull-

7 Cal)le-olieratctl carryall scuol)s S/I I cu. yd.

3 Light ant1 I metliuni 1)iieuiiiatic-tyrt.tl tractors j IIeavy-duty motor graders. I Tractor-tlr:rwn heavy grader. S 1)oul)le-druni and I treble-tlrum sheepsfuot

rollers used it1 3 sets. 3 1’iicuiiiatie-tyi-c.rl rollers. 3 6-2 ton xtiio~~tli iron-tyrctl rollers. 6 \\rater tanks for truck mountiiig:. littetl w i th

I “Uarl,er ( ircene” trenclier ( f o r excavatiiig pipe

vator. littetl as I)acli tlitclier and

Fuelling ant1 servicing of the plant was carried ( J L I ~ i n the lieltl. F u r this p i i r p s c ~ a motor truck was stocked with tlie full range of fuels and lubricants re- quired and fitted mit with lul)ri ting equipment antl suficient tools f u r minor repai The truck driver antl a serviceman who travelled th the truck carried out all servicing operations.

Soon after commencement of the work a field course of two wecks’ duration \vas conducted at tlic aero- drome by the Del’arttnent’s School of Plant Instruc- tion, antl all plant operators were given instruction in tlie maintenancc antl operation of the plant items in use. I t was found that, following attendance at this course. tlie operators were more proficient and tlier- was a marked increase in output, particnlarly of the tractor-scoop units.

A feature of tlie work thrtingliuut was the care takcri to eiisure a smooth pavement surface with good riding qualities for aircraft at high speeds.

The hituminous surfacing of the pavements was put in hand by the Cotnmoiiwealtli Dcpartmcirt of Works and FIousing antl is not part of tlie work under- taken by the Dcpartnient of Main Roads.

were :-

dozcr attachments.

capacity.

slrrayer liar.

Ircnches).

risctl ~r&idicaIly its :I crane.

MAIN ROADS. Vol. XII, No. 4. -

I16

The Origin and Destination Survev of Road Traffic in the City of‘ Sydncv. d

MAY, 1947.

a

In its attack on the prol)lem of road planning i i i

the Sydney Lfetropolis (see article “l’laiming Activi- ties” in the Septetnl)er. 1946. iimiI>er of this Journal) t lw 1 kpai-tmcnt rccrrgnisrrl thr iirce.;sity fur niitcli more coiiipreliensive traffic tl:ita tlim was :iv:iiIahle. 2 1

simple crrunt ( i f traflic using thc \-aririu.: streets \voultl LI the rcqiiii-cmtwts o f ti-atiic.. Irecause when

traftic facilities are tinsuital)le or inatlequrcte bomr tr:ilfic is forced to follow routes which ai-e neither suitable iicir logid. There was a need. therefore. ior (lata sho\ving i)mh froin where traffic was coining from and t i r d i e r e i t \vas pruccediiig. ‘The tileans o f ~rI~t;iiiiiiig S W I I tiat:i is tlic ”( )rigin and Destination Survey.” It ma!. be of interest first to give a bricf outline nf the v;iricr~is 1-rccigiiisetl iiiethotls. settiiig ou t auiiie of their advatitages and disadvantages.

Morning Peak Hour on Sydney Harbour Bridae. Cards were iasued to this traffic as quickly as it could pass through the Toll Barrier,

June, 1947 MAIN ROAM. 117 ~~~

I i

i

Cards have been collected in background from the vehicles in this steady stream of two lanes of traffic leavinc the inner City along Broadway. Cards are being collected from the drivers O F vehicles at the kerb.

( L I ) H o i i i c ~ oriri 1:r r s i l i c~s . s I i r t c w i m ~

Of recent years this nietliotl has I)eeii devclml~etl Iiy the Public lioads .\tllliinistrati[)li ( G.S,,\.) in coilju~ic- tion with the Unitetl States liurrau o f Statistics. Based upon detailed information concerning the atltlresses and nuni1)ers of ~ l w c l l i ~ i ~ s in each street block. specific tlwellings- say j ])er cent. of the tntal-are selected antl iritrrviewcrs c;ill on the occupants of those par- ticular dwellings to d ~ t a i n co1iilirche11sive information regarding tlaily travel Iiy all occupants. Sonletitnes several calls have to I)e matle in order to interview the occupant. )perators of commercial vehicles, repi-csciitiiig, say. 20 per cent. of the total commercial vehicles. are intervic\vctl at their place of busine

This method furnishes the moat cotnplete data of all the methods that have come under notice, antl is the methutl in riiust favour in the IJnited States. There are serious obstacles. however. to its application to Sydney at the present time. some of these being. :-

Interviews, : ~ ~ i d tahulation and analysis of as- semliletl data would involve trained irian1xiwer which it would lie (litticult i f not impossible to nhtain at tlir present time.

Traffic entering City at Railway Square. The issue of cards in the background of photo. has not interrupted

the steady stream of traffic.

I n IJI-tlinary C ~ ~ C ~ I I ~ I S I : L I ~ I ~ C S :I hurvcy by this method occupies many months ;ind. in vicw of the difficulties indicated almve. it is impro1)able that the analysis o f such a survey could I x avail- able in less than eighteen months or two yeai-s.

( 1 1 ) Postrd C)iirstiorriiuiri- t o nll Moto,, V(~lriclr 0 ~ 1 1 r r . c . All motor vehicle owners ;ire posted a card antl

are asked to answer stated questions atid return the completed card.

Although no field staff is required. much work would 1)e involved in pi-el)aratioii of mailing lists i n the case o f Sydney wlicre records o f inetrol)olit;in car owiiers are not listed separately from those of other areas. C’oiiinioii experience overseas is that the percentage o f ~icople \vIio complrte antl return the rarils is i l i i a p - pointingly sinall.

MAIN ROADS. - Vol. XII, No. 4.

Detailed inspection of card collected at outlet station when traffic not heavy.

( r ) Xecordiiig rcqistrcitioii iiriiiibrrs of w h i c l e s parked

The rrgistratiun ntiiiilws of vehicles parkcd in the City are recorded atid information as to the place of residence or business of these o\vtiers is obtained from the Ikpartnrent controlling vehicle registrations.

This method does not give iiiformation regarding the time the vehicle entered the City ; it does not give iiiiorrnatioii rrgartling vehicles which pass through the City without stopping. nor does it give information about any trips uthcr than thusc coinmeiiciiig or ter- miiiatitig at the address of the owner.

( d ) Rrcordirr!/ rr,qistriitiuii irrrrizbrrs of whiclc~s ptrssiiig

l k c h time ii vehicle pa. s each o f a series of tratfic stations its registrat nuinber a i d the titiic of passing are recorded. 'I'he route taken by the vehicle through the area covered Iry the survey caii later he traced from station to station.

T h e whole of the records of registration numliers iiiust be made on the one (lay, and thus a very large field staff is required. Analysis of tlie information is lengthy and involved. Moreover. a high degree of accuracy in recording registration numl)ers cannot be achievcd where traflic is dense. This method was used by the Department and the lluiiicipal Council of Sydney earlier tCJ study trafhc entering a i d leaving thc I'yrinont peninsula.

( e ) IIuirdl'tt,q Postill Qrrcstioilriairc ( ' ( i d to dr i zws . A postal card is hantletl to the tlrivcr of each vehicle

passing each traflic station. The card to stated questions. including the origin ancl tlestina- tion of their journey.

This method is siinple. but experience is that a tlis- appoiiitingly small proportion of c:trtls are cornpletctl and returned.

iri tlrr City.

trnf ie stntioiis.

June, 1947 MAIN ROADS. I I9

Having regard to the factors of time, manpower. available data on distribution of dwellings, and the volumes of traffic to he dealt with, iioiie of the fore- going nicthnds Iiy itself was considered suitable for the Sydney Trallic Survey. X method considered to be suitable for survey of traftic passing through '+e central area of the City at the present time was formu- lated, but until recent months traffic liad not sufh- cietitly recovered from war-time restrictions to justify carrying out the survey. This method Wa: adopted by the Joint Corninittee on Tramc ancl Parking on which are repre..rented the Municipal Council of Sydney, the Department of Slain Roads, the Cumber- land County Council, the Department of Road Trans- port and Tramways and the Police Department. All Ihcse authorities co-opcratctl in carrying out the recent Survey which was authorised by the Minister for Transport. The following gives an outline of the

method which, of course. will not complete iiifornia- t inn rcgardiiig vehicles which remained in the central area of the City af ter 7 1i.m. or vchicles which did n r i t lcave tlie cordoned area during the entire period o f Survey.

-1 cortlon of t\veiity-threr traftic stations controlling all lines o f road acccsb into tlir inlier City was estab- lislietl. (See tigure 2 ) . Each time a vcliiclc other thaii ; I tram, litis. ;iiiiI~tilai~ce. Fire Hrig;de or funer;il vehicle. entered the inlier City through any one of these stations 1)etwcen the hours of 6.4j a.m. atid 7.0 1i.m.. tlie driver \vas issued a "l'assenger \‘chicle" 01-

"Coniinercial Vehicle" ~ ~ t l bearing at the top right- haiitl c(mier a four digit code number representing tlie ststioii of issue and the quarter-liour period o f issue. I Iiesc rai-rls :ire illustrated in Figure I . Drivers passing through tlie City corrloii area without making a call were I-eqiiiretl to answer questions on the front of the card only. and they could rcadily do this at the hrst City street intersection at which they were halted by crossing tt'atfic. Those making a call within the City were asked t u fill in the back of the card also, ancl this could be h i e in a few seconds while the vehicle was stationar).. The cards to bc issued at each Station were rlcliveretl there in envelopes or packages endorsed as in Figure 3. The 40 is the Station nu111-

r .

CODE 4015

PASSENGER ALLOTTEO 120 UNISSUED __

IO 45 to 10.30 a.m. Figure 3.

ber which is also given lip the first two digits of the code numlier, die last two digits of the code number representing the quarter-hour period o f issue. The cards were removed from the envelope at the hegiii- ning of the quarter-hour period. atid at thc elid of that period the retiiaining unissued cards were returned to the envelope.

The completed cards were collected from drivers of vehicles as they left the cortlon area. Those col- lected cadi quarter-hour were placed in envelopes or packages endorsed as in Figure 4.

CODE . . . 3945

PASSENGER COMMERCIAL-

TOTAL - 5.45 to 6 . 0 0 p m . Figure 4.

Drivers who (lid not surrciitler a card as they left the City-that is, those nho had lost their card o r

MAIN ROADS. Vol. XII, No. 4. ~

120

who hatl 1)ccii ill the City when the Survey coiiimenced at 6.45 :i.iii,-were hatitlctl n postal card as shcrwn i n Figure 5

S? l ? J R L

Figure 5.

L i t St;ttions wllcrc cards were collected. the estent I) i examiilation of cards ;ti id assistance to drivers i i i completiciii of cards varied according to the volume of tl-;itlic. \\'liere traffic \v:ts not very heavy the front ;ind. if ~rossiilrle. the back of the card were examined and coml)letetl 11y tlie collector. rir thc driver was asked t o go to tlie kerb where other ofticers Iilletl in tlrc card. 'l'liese crlliccrs alsr) reccirtlrtl the origin antl tlestiiiation of :dl vehicles t o wliicll 1)ostt:iI nirrlh WCIW isiuctl ;is :in ;tdditioiiaI cliecli in vie\\. of tlw p(issi1dity that many 1wst;il cards might not be returned. \\:hen traffic was very heavy tlie cards were collectetl witliottt esaiiiinatioii.

'rlie cards t o be issued at each Inlet Statioii were tleliveretl to the Station. packed iii I~oses. from IO to 20 minutes 1)efoi-e the Survey commencetl. The cards collected at ( hitlet Stations \\-ercz ti-ansferred to the 1)el)artment's oftice at iiitcrv;ils during the rlay. IIere tlie cards in each envelope were entlorsetl with ccitlc iiuiiil)crs intlic;iting the station atid quarter-hour period o f collection.

Tlirocighout the survey traftic was controlled by one or more I'olice Constables at each Station. Special I'arliing I'olice Iiandetl cards to and received cards froin tlriizers. and in this they were assisted by officers from tlie four :iuthorities co-operating in the Survey. 'I'lic otticcrs h;cnrletl cards to and receivecl cards from the Speci:il l'arkiiig L'olicr at the I~eginning a t i d end of each quarter-hour periotl. ( )tiicers also stood :it the kerb to assist in filling in cards of drivers directed to thein. The staff employed other thati l'iilicc \\ere Cards being issued to two lanes O F traffic.

June, 1947 121 MAIN ROADS. .~ - ~~ ~

perccntagc figures concerning the completeness of t h v cards collected. I t is interesting to note, however, that even in the case where the driver did not eiitei- any information on tlie card, tlie cude numbers U I I the card indicate the time and place of both entering and leaving the City cortlon.

The Survey organisation worked smoothly and only minor delays wcre experienced by traffic. At some hcavily trafticketl points traftic passed as freely as on ortlinarv days. antl at no point was serious congestion causctl 1 ) ~ tlie Survey.

This article was written a few days after the Survcy. The collected cainls were then being edited and code nniiiliers fo i - sul~url~s of origin antl rlestinati~rn adtlerl. E’roni the collected and coded cards. “f’omers” tal)u- lat’n!: ni:icliiiic cards were punched hy the New South \\‘ales Hureau of Statistics antl Ecunomics, ant1 within :I iciv (lays tlic liureau commencetl the machine tlissec- t iun of tlie data on the cartls. ne of these cards is

O O O o o O o O o O O o O o o O O O

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

7 7 1 7 7 , , 7 7 1 7 , 1 7 1 , 7 7

. . 8 1 8 1 1 * 1 8 1 1 1 1 * 1 1 8

Finure 6.

illustrated in Figure 6. Reading from the lett the holes punched in this card show that the vehicle repre- sented by it left the City through Station 01 (Harbour Bridge) at time period +J (6.45 to 7.0 p.m.), entered the City through Station No. I O (William Street) a t time period 12 (5.0 to 5.15 p m . ) . was a type 7 (Com- mercial) vehicle, came from suburb yrg (Rose Bay) antl proceeded to suhurb 232 (Roseville). first place of call i n thc City was zone 070 (between King, Eliza- hctli. Park and George Streets), desired longest park- inl: period i n zone 020 (between Margaret, George and Market Streets and Darling Harbour), and last place of call i n the City was in zone or I (north of Margaret Street and west of tieorge Street).

The results of the machine dissectiun of the punched cards will he tabulated antl :inalysed by the Depart- ment on hehalf of tlie joint Committee on Trafic antl Parking. The Technical Sub-committee will report on the Survey to the Joint Committee and to tlie City Roadways Planning Conference. The Joint Committee will use the data in studying traffic conditions. and the Conference will use it to assist i n the examination oi the problem of future arterial roads to serve the City. The data will be verv valuable to tlie Denartnient in the planning of main roads linking to arterial roads in the City.

As soon as practicahle some of the assemliled data will he presented in the form of maps with “traffic desire lines” showing the volumes of traffic linking the varions origins and destinations. r\ summary will be published in an early nurnher of this Journal.

~

PAYMENTS FROM THE ROADS FUNDS FOR PERIOD 1st JULY, 1946, to 31st MARCH, 1947. Aniount Paill.

439.132 C‘CIr’NTI. I l k C‘I ’ \ lR l ; .UL. \Nl l M I N b!Oz\DS 1:C-NE- t

. . . . . . . . . . . . . . . . . . . . . . . . . C‘onstruction of Koads and Hridpcc . . . . . . . . . . . . . . . . . . . . . . . Cost of Acqiiisitioii of Land i o r ~ K n denilia 6 m

hkiinteiiaiicr nf Koada and Bridges J i X i , 8 l L 11s . . . . . . . . . . . . . . . .;7.622

Other ISspenditure . . . . . . . . . . . . . . . . . . . X2..j%

. . . . . . . . . . . . . . . . . . . . . . . . . f686,.&

Cmstruction of Roads and Bridges . . . . . . . . . . . . . 561,763 Cost of Acquisition ( i f Land iur Roac

Interest. Exchange and Repayment o Purchasr aiid Repair of Plant and 2,38,8?1, Other Iixpciiditure x4.252

. . . . . . . . . . . . . . . . . . . . . . .

~~

~ ‘ I I l ~ X ’ l R Y M A I S 1<i).\llS I’UX>

1,449 Maintenance of Roads and Bridges 1.413074

I40.544 hl

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . fr.j39,grr

I ) K V K I A I P I I EN’I‘AI. Ru.\iis P Y X + C m ~ a t r u c t i ~ ~ n cif Riiails and Rriilgrs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L . ; , I ~ I

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Expenditure 3.150

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . f28.6.3c

SUM M A R Y ALI. FUNDS- Constructinn of Roads and Bridges . . . . . . . . . . Cost o f i\cquisitinn of I.and for Road Widen . . . . . . . . . . .

Interest. lischaiigc and Kepayrneiit nf Loans . . . . . 1iP.166 Pi i rchse and Repair of Plaiit and Motor Veh’ Othcr Ikpciidittire . . . . . . . . I j0.29;

Maintenancc o f fiiidils and Bridges . . . . . . . . . . . . . . . . . . . . 1.j1.3.886

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total . . . . . . , . , . I . . . , . , , . , , . . . , , . , ,

Vol. XII, No. 4. . -

Developmental Roads and Developmental Works.

toad iml)roveineiit liar1 not lielit pace with the t levelq- iiient of motor traffic. Even in the older settled rural areas niaiiy roads were uiicotiatt-uctetl atid uiisuitable foi- use by motor vehicles. For wiiie ycars after the .\rt caiiic into operation therefcirr. little tlitticulty was experienced in selecting rci:itls sc~itnlile fur proclamation ;is tlevelol)nieiital roads.

By the end uf ~(p,.;. t ~ ~ ~ ~ ~ ~ J ~ ~ l l l ~ l l t ; l ~ riiails with i m ;iggregatr Imgtli o f 2.797 miles had ticen proclait~ietl anti. (hiring that saiiic period. (itl~cr Shire i-ci;ltls having a total length of -..xX miles \vitre Iiroclaicnc(l ;is iiiain riiatls in atlrliti(rn to the IZ.S+J miles oi iiiaiii rwatl ~iroclaimetl :is at the ~ 0 t h Juiic. ~ ( j A i . ;\ review o f the position at that stage intlicated rhat this ctrnil>iilerl total o f 5.02.j milca inclutletl the mnrc iiiiportmt of the roads in use then reqiiiring constructirin oii the w h d e or a tiiajrii- part nC their lengtlls. '1'1w remniiiing utirlassilic~l roatls in use iiiclutle(1 tiiaiiy i t ) ;irc;ls capalilc of furthrr

..

Ucveloprnental Road No . 1148-Tabulam-Ex~in~ar.

Developmental Road No 1148. Tabulam-Ewingar. Bridge over Rocky River

tleveloiiment which ( I I c l no t qualify for ~ i r o ~ ~ l : i i ~ i ~ ~ t i ~ , ~ l as tleveloiitnental I-oatls :is regards the whole or a inajor portirin of their lengths. I n this ca~cg:ory \Vere LII~COII- structetl road., i i i [lie iiiiire hparsely settletl districts or areas with linritetl ~)r(ispective tleveloliment on which construction wi rk c(iultl lie justified o n l y in respect of a n occasional tlifticult section : a l ~ roatls in tlie more closely settlrtl districts Lvliich had lieen cotihtructetl or inilirovcd in earlier years for LISP Iiy horse-rlrawii vehicles liiit i:iiletl t ( i meet ~rcasotialile needs Iiy reason o f some isolatrtl dist;icle t u ni~itor trattic. In numerous instances certain worlis required ~ I I 1-cniovc the iiiajcr ~il~stacles to trattic on these two g rmps o f roatls could lie reg:;irtletl its necesiar: for the tlevelopn:ent of the district (ir thc arca served.

In order that thr l)rvelrilimentaI Roads Fuiitl might be used in siicli cases. the provisions of tlie :\et rdatin? tn tlevelopmental r(iatls werr amctirletl i n 1037 to include tlevel~ipmeiital works.

Under section 30 ( I ) of the Act. any Cnuiicil may apply to the C o m m i s ~ i o ~ ~ e r for the ~iroclamation of a road as a tlevrloli~nental road or of ;i work as a develop- meiital work. In order to Iw eligil)le for ~iroclamation the road or work must come within one or other of the iiro categories provitletl in section 28 ( I ) . An

aplilication. therefore. should be ;icc~riiiiiaiiictl 11y infcir- mation to s h v -

( ( I ) that the con~tructi~rn o f the ro;itl or work w i i i l i l assist the tlevel~qimcnt o f a rlihtrict Iry Iirovitling or improving tlir rc)atl ctiniiiiunica- tion within tlie district or I J ~ prcivitling new or Iiettei- ineans o f crimmunication with other districts. ports or markets ; or

( 1 1 ) that the construction nf the road or work is necessary to provide access to an area which otherwise roultl not lie used to atlvantaye for the puriioses it is hest arlaptcd.

Since the ccinstruction of Iirciclaimetl clevclolitnental roads antl works involves the expenditure of public funds. tlie Cominissi~iner must be satisfied Iieforr re- comtnen~liiig pr~iclamation that there are good grounds for anticipating a direct or indirect henelit to the State conimenwrate with the cost o f nece itivcstigatinn o f all ~iroliosals suhm iiecessary and must take into ac~oi in t some or all of tlie following c~rnditions :-

Existing land settlrniriit and pr~rcluctiri~i. the pre- sent iise o f land antl the purposes for which it is best atlalited.

Existing means of transport antl communicatioti other than by road.

124 Vol. XII, NO. 4. h U l N ROADS. ~ ~ ~~ ~~ ~

-~

r . J lie extent to which de~~e lopmr~ i t may he tlrpeti dent ulwn public works other than road works aiitl any Iiublic works in coiiteml'latioii.

lkistiiig conditions in respect of road access ; i t id conitiiunicatiort and the nature atitl cost of iiecebsary construction works.

The funtls l~econiitig avail:il)lc for tleveloptuental roatl wiirlis from time to time are not siilticiciit to en:il)lc carly ~)rnvis i im I ~ I lie m:itle for all works which can I W reg;irtlrtl as tlevelolmietital in character and. subject t ( i a reas~~tialilp tlistributioti o f the av;iilal)lc futitls. it is necessary to tliscrimiiiate in favour of the works of greatest Ilenetit t o the coti~iii~~iiity having regard to c~iiisitlcratiotis of cost. 111 this way the 1kp;irtrnent seeks to provi(lc for orderly Imgressive tlevelolmetit o i the v;irious Iiarts of the St;ilc i l l so far as tleveloI)metit is tlepciltletit I I I M I I I road coiistruction w(irks.

i)evelolmiental road construction iicetls to l)e coii- sideretl iii I-elation to the gctieral cl~iestion o f i-oa(l tr;insport a i d communicatioti. The I klxirtiiiciit is cti- tieavoitring to olitairi a coiiiplete picture of developnieii- tal rri;id requirements in conjutrctioii with a general review c i f the main roads system of the State. which is licitig carrietl out on ;i regioiial Iiasis. I lie invcstijia- [i(iiis nccrcs;iry for these imrposes cot 'hlocll of the in foriiiation required is not readilx avail- alile and can lie ol,tainecl ritily as a result of a coiiipre-

,.

hciisive survey of cuntlitioiis ai i t l i-estiurces. The Carr!-- itig out of siicli a survey is a major function of the Regional I~evelopnient Chmit tees , and it is anticipated that the results. when available, will ni;iterially assist the 1)epartnieiit i n its consideration of pi-o~i~isals for roar1 tlevelnptiieiit.

The diagram ( fig. 1 ) shows tlie nilc cage nf develop- mcmtal roads whicli had I)ecn prwlaimetl at the cnd of each ycar 19rg t o I!)+(I : :dso the l)rq)ortiiin of the total Ietijith subseciueiitly reclassitietl ;iiitl iiicludetl in the i i i a i t i road system each year. atid the proportion which reverted to tlic former unclassit;etl status. In all. 3,672 miles Of tlei~eloprnental roads had IWXII proclaimed at thc end of 1946. Of that leiifith. riintls having total length of 070 miles hat1 Iwen iiicorl1iir:itccl in the main r(iatls systeni ant1 :ili(iut ISO miles were dclirocl;iimetl for v;irk)iis reasons. I)evelo~~iiie~i~;il \vorlis have bee!> pi-~icl;iiiiietl each year sincc the aiiicn~li~iciit of the Act in 1937. tlie tl i t ; i l iiiiiiilier (it' such works ;it the Alst I)ecember, I()& being fifty-thret ( 5.3 ) .

1 he expeiitliture each year on develolitiietital roacls and works is set out in a table on page 12j , the amounts shown being exclusive of any contrilicttiotis niatle by cnniicils towards the cost of the wnrlis.

I n espeiiditure of the tot:il siitii oi F_..,-yj.SS; sliowi i n st;itement oii page 125. approsim;itely I .Sgo I n i l r i of new construction were completetl on jirocktimed

- .

Developmental Road No, 1007, Arthurville-Geurie,

June, 1947 MAIN ROADS. I25

P --

devclopinmtal road5 t o thr 30th June. “&, nnrl thirty- tive devrlolimcntal \\ orhs 31w had been completed at that date. 1925-20

1920-27 1927-28 1928 29 7929-30 193*3I 1931 3 2 1932-33 1933-34 ‘934 35 1935-3” 193ft-37 1937-38 1938-39 1939-40 194ct-11 1947-42 1942-43 1943-44 1944-45 1945-4f’

. . .

...

...

...

...

. . .

. . . 1 . .

...

...

...

...

...

...

...

...

...

...

...

...

. . .

...

. . .

...

...

. . .

...

...

...

...

...

...

...

. . I

...

...

. I .

...

...

...

...

...

...

. . .

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

...

i ... 10r,qf,Y ... 152PJ7 ... 195,304 ... 3 7 o . w ... 35 1,124 ... 206,597 ... 39,768 1 . . 57.255 ... 114,352 ... 279,161 ... 172345 ... 98,445 ... 83,325 ... 102,489 ... 1493901 ... 171,390 ... 85,332 ... 16,892 ... 9,498 ... 13,560 . . . 30.277

Total Expenditure, 1925-46 ... L2,799,885

n

-~ 126 MAIN ROADS. Vol. XII, No. 4.

SYDNEY HARBOUR BRIDGE ACCOUNT. Income and Expenditure for the period 1st July, 1946, to 31st March, 1947.

liiconir. Erpcriditlrrr.

~~ .- ~ ~~ ~~~ ~ ~ ~ _ _ _ ~ ~ ~ ~ ~ ~ ~ ~~~~ ~~ ~~ ~~ -~ ~~~~

f f . . . . . . 9 . j l O Road Tolls 237.31 I Cost of Collecting Itoad Tolls . . . . . . .

Contriliiititnis- hiaintciraiicc and Miiior Improvcmelits . . . . . . . . . . . 3 3 2 O i . . . . . . . . . . . . . . q.;,y~o :\ltrrations to Archways . . . . . . . . . 6.472

747

. . . . . . . . . . . . . . . . . . . . .

Railway I’assrngcrs ‘l‘ramway I’aasriigers . . . . . . . . . . . . . . . . . . . . . . . . . 14,160 .<dministrative I W e i i w . . . . t . . . . Omnihus Passengers . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ..$L -’ Loan Charges-

Rent from Properties . . . . . . . . . . . . . . . . . j ,zjn Tiitcrest . . . . . . . . . . . . . . . . . . . . . . . 1 ~ 8 . i . S i Exchange . . . . . . . . . . . . . . . . . . . . . . . 26,475 Sinking Fund . . . . . . . . . . . . . . . . . . . . . . . . ~ I , O C X ,

~ 276.125

f361.340 f326.361

New Vessel €or Newcastle-Stockton Fcrry Service.

a

The vehicular ferry service across l’ort lgiinter between Newcastle and Stockton was inaugurated in 1916 by the I’ublic \fiorks Department. using thc S.S. “Miltlretl” which had bceti specially built for tlie pur- pose to carry tifteen vehicles. In 1930. tlie control of this service passed to the Main Roads Board (now the Department of Main Roads) which, i n 1932. pLircIiaset1 tlie S . S . ”Kooroongaba” (of thirty-five vehicles capacitl-) from Sydney Ferries to cope with tlic increase in traffic. The smaller “Miltlred” then became the relief and supplementary vessel for the next 14 years.

Owing to tlie advancing age of the “Miltlretl” and the increasing cost of overhaul. and also because of its limited capacity when relieving. replacement of this vessel became desirable ant1 when the bridge over the nrrwent River at TIohart was oprned ill 1c)44. the

L)ep:irtment took the opportunity t o ptirchase the S.S. “Lurgureiia,” of 47 veliicles capacity, wliicli had carrictl tlie traffic between ]Hobart and Hellerive.

The “Lurguretia“ is a sister ship of the S.S. “Knlatig” which. prior tu its iiiipressment for war service. was operated by Sydney Ferries as a “showbnat” o i i Sytl- 11ey Harl)our. I t \\-as built at S:iltncy Shipyard, Chester. Englaiitl, Iiy J . Cricliton Rr Co. Ltd. I t h:is ;iii

overall length of 199 feet, extreme brc~atlth of 3s feet 3% itiches, antl moultlctl tlcpth of 1 4 fcct ; grnss ton- wigc is 5 5 2 , net tonnage @. and it is driven 11)- trildtl expansion engines (leveloping I , 1 5 0 iiiilicatetl horse power at 1s0 111. stcani pressure.

Cnnsit1eral)le repairs were iieccss;ir? before the “Im-jitirena” could iiiitlertakc the vtr!-:igc to New- castle. Tlicsc repairs wcre carried out Iry two Hobart

June, 1947 MAIN ROADS. 127 -

i

firms, and arraiigenictits for protection of the vessel frotii waves were similar to those for tllc original voyage of the vessel frcim Etiglantl to Hobart in 1924. A contract was Ict to hfr. ti. Kewell of Sydney. fur delivery to Newcastle and the vcsscl arrived there o i l

Christmas Eve, 1945. Since arriving at Newcastlc frirtlier overhauls have

been carried out and thc vessel Iias been fitted with the lifeboats antl equipment required for its usc as a ferry vessel. The Navigation Ileparttncnt has issued a certi- ficate for the vessel certifying its calm-it!? as 47 vehicles antl 274 passengers.

The placing cif the vcsscl on the run was delayed because its draft of feet is approximately I foot greater than that of the S . S . “Kooroongaba,” and it was necessary to await dredging of the channel to allow the vessel to cntrr the (locks at Stockton. A trial run was matlr during ktolwr last at high title. antl the vessel was put into scrvicr i n Iilace of the “Koorooiigaba” on 6th Dcceinlirr. 1946,

The Iihotogral)ll above shows tlic “Lurgurena” as slic appeared when put into service at Newcastlc, with the alterations tiiade to provide foi- better visibility from tlic wheel house.

Tenders Accepted. The following Tenders (execcding &joo) were accepted by the Department during the months of Januarv,

February and March, 1947 :- ~. ~ -.

council. ’ Road Work. Tenderer. Amount. 1 1 No. -.

L s . d . Barraba S. ... h3 Construction of approaches to reinforced concrete bridge E. tV. Hall, ninnaway 1 . 0 2 4 5 4

over Cobbailah Creek.

at Coolbaggie Creek ani1 c~incri’te hoa culvert at 2 0 111. r30q ft. from Duhho.

!

I j . L , O S L I ~ o Talhragar S . ... Constiuction uf appr(iac11es t o reinforced concrctc bridge J and A . Lighezzolgi, Connaharabran.

I28 MAIN ROADS. Vol. XII, No. 4.

Supply 1 1 1 3X tons biturnen ... ... ... . , , . . .

Supply and delivery of io,ooo c. yds. filling hetween Mil- perra Hoad and Fleurbaix Avenue.

Supply and delivery of 3,000 c. yds filling . , . ... ... Supply and delivery nf 1 . 2 1 0 tons of aggregate . ._ ...

Supply and spraying of 2r),3Xo gals. bitumen .. . . _ .

Supply, delivery and spreading 3.5rX E . yrls gravel ... . _ .

Bituminous resealing of 59,bo6 sq, yds. between i . 3 ~ m

Supply and application of 7..jsn gals. of biturnen ._ .

Supply. delivery and spreading 4 , w u c. yds gravel ...

and 7.05 rn. from Orange towards Mt. Canobolas.

Thc following Tenders (esceeding A50o) were accepted by the rcspective councils during the montlrs nf January, February and M a r c h ~ q 4 7 :-

IV. B. Carr ( 'mstruc-

Burfield's Pty. l . t<l . ... : lions.

. . . I Blue Metal ancl Gravel

Pty. I.td. i W. B. Carr Ciinstruc~

tions. Miller and 1.ewinqtim ... B.H.P. By-l'rorlucts

H.H.1'. Hy-l'rwlucth

...

Pty. 1 , td

TYII T t r l

AshfordS. _ . . I 134 1.3:

Rankstown hl. ... 508

Supply, delivery antl spreading 440 c. yds of aggregate _ . . Supply, delivery and spreading 5.280 c. yds. gravel _ . . Construction o m. 2.400 ft.-13 m. 2.054 ft . from Marrar . . .

Supply and delivery of 310 c. yds. of +-in. and 330 c . yds. of &-in. aggregate.

. . . . . .

~ -i ' I-..' H. G. Fulcher . _ . . . . U. A. Ne\c.man aid Sons1 E. S. I'restun and J

C. I<. Wilkins . ._ .. . Bromfield.

... I b j Carrathool S . . . . 244 ('nolamon S . . . . loo1

Surfacing z m. 4,795 ft.--Clm. 500 ft. S o r t h Wagga ... Supply and delivery of aggregate ... ... _. . . . . Bituminous resurfacing 37.000 sq. yds. . .. , , . . . .

. . . I8 . . . I I 1

... I 1

do . . . I 11. IV. Snell ... ... , B .H.P . By-l'roductri

P ty . Ltd. I

Gonbang S . . . . I

water Road.

bulk bitumen. Supply and spraying 7,750 gals. and supplying 3.200 gals.,

Harwood S . 1 1;;; Hume S. ... I.iverpool Plains S . ... Macintyre s. . . . I ...

Mitchell S . ... 57

I3.tl.f'. By-l'rixlucts P ty . Ltd.

.,. 57 Moama M. _. . L I Yarraburra S . ... I 57

Narromine M . . . 354

Resurfacing 31.X78 sq. yds. . . . ... _ . . . . . Hesurfacing 37,312 sq. yds. _. . . . . . . . ...I

Resheeting with loam three sections hetween 23.5 in. and

Supply, delivery and spreading 5 ,120 c. yds between PI^

Supply, delivery and spreading 12,ggr c. yds. gravel from

Supply and delivery of i ,o96 tons of crushed aggregate

Reseal 14.146 sq. yds. . ._ .. , ... _ , . , . .

41 in.

m. and 230 111.

234.5 m. t o 2 7 5 . 1 m.

f.0.r. Greenethorpe. Supply of aggregate for patching and sealing ... ...

Constructiun, including culverts and gravelling ... ... Supply and application of Duratenax ._. .,. ...

I 373 Tenterfield If. ... Xessrs Cheslerfield anrll}

D. A. Newman and Sons,

H. McClellan ancl Death

C. J . Caviu _. . . . .

Blue Metal and Gravel.'

Jenkins.

Pty. Ltd. n.H.r. Ry-I'rociuctsm

Pty. Ltd. . . .

Australian Gas-Light.

C. Howe ... . . . CO.

I6

Weddin S. .. . ' G

... b

... h

\Vollondilly S . ._ . rg')

Yanko S. ... I108

... ...

Work. 1 Tenderer. I I

Supply and delivery of 692 c. yds of f-in. aggregate and

Supply and delivery of 4,708 c. yds. of gravel ... Supply and rlelivcry of 10.587 c. ydsof gravel ... . . . Supply and delivery of 675 c . yds. nf f-in. aud 202 c. yds.

Supply. delivery and spreading 25,0<,4 c. yds. gravel ...

108 c. yds. < i f 8-in. aggregate. . ..

of f-in. aggregate.

Construction of 14 m. towards Richmond Range ... . . . I Construction of approaches Fowlers Swamp Creek .. . Formation and gravelling on Hreeza-Carroll Road . .. . . . Scarifying and reshaping sections 4 9 . 1 1 ~ lin. ft. and supply

Bituminous resurfacing 22,ooo s q yds. ... ... ... and spread gravel 19,587 c. yds.

T. 4 . k'iefke . _ . . . . I J . antl A . I.ighezzolo . . . I

. . , I C. R. Wilkins ... . . . '

.\Iessrs 'rnrrrns ani11 Wnoden.

Murrav and Co . . E. J . ilathrws I I?. W. Hall ... L. M', Keft . , .

H H.P. Ry-l'rtaluct.;/ P tv . Ltd.

MAIN R O A D S STANDARDS. NOTE: -Numbers prefixed by " A " are drawings, the remninder are specifications unless o:herwise noted.

j O c ) * l n s t r u c i i ~ n i ~ io r Dcsigii of Urban Iioarls (rqjq). 70' I'ormation. (hv i scc l , Jnly, 1946.) 238 Instriictir,nh lor Dchign ol Inte~sections ( I ~ J ~ < I ) .

p z Instructinns for 1)wign of K u r d Intersections (accclera-

EARTHWORKS AND FORMATION. l ~ o l m srt. PCll m XO.

Integral Concrctc Kerb anrl Gutter antl Vehicle aiid Dish

A 1532' Standard T y p c a l C.ross-scctians. ..\ Ir4'J* I;lat C.ountry Cross-section, Type 4 . (l<evi~ecl, t,,s<:.) A I I p * Flat Country Cross-section, Tvpe R. (lievise<l, 1<130.) , A 1151' I'lat Country Cross-section. Type D I . (Revised, i < , j t ~ . )

A I l s r* I'lat Country Crov-section, Type Dz. (Kevised, 1930.) ~ ,XI, July, 193')) and Drawing. (4134A). A 142; Flat Country Cross-srction. Type Et. (Revised, 1q3i . ) 1 245 G , , May, 1939) and Drawings (a) with A 1101 Typical Cross-section One-way 1;eeder lioad. (1y30.) 1 grating (A 104') ; (h ) Kerb inlet only (.A 1043) ; 11 1 1 0 2 Typical Cross-section Two-way Feeder ltoad. ! (ri with grating and extended kerh ink t (-4 1 3 j 2 ) : A 8.3 Earthworks Ouantity L~iagram. ! ( d ) rxtcmtlvd kerb inlet (.I 1353). A 114 Rubble Ketncnin: \ \ a l l .

tion sml deceleration lanes). KERBS, GUTTERS, A N D GULLY P I T S .

'243 i

i A r!iu G ~ I I ~ crat ing. ("133 )

FENCING.

2 7 1

2 7 2 St?ting out si& nidths (instruction for "be of t a p p h i t i . i I

Settinr: out sitlc widtiih (iriitruction for iisc of ~ ~ n l i i i t ~ ~ y i .A 1413 Cuncretc Convcrtcr.

142 Split I'oit a n r l l h i1 I'encing atid I h n i n g (.\ 43) . 141' Post and \Vire I'encing (Rrvisrri, September, 1,934) and

survey in . i t runi i~~t s ) .

Drawings (LO I'lnin (.\ 494) ; (6) Itabbit-proof ( 4 4qX) ;

r43 Ordn;ln(.e I'cncing (I!evise,l, I;<;hruary, 1934) and (c ) Flood gate (A 316).

1)rawing I\ 7. :l\~clllcllts. i

( I ~ c v ~ s c d . November, 1r)3~1.) (Ikviyed, J i inuxy, 1<13<1.)

7 ~ * Hroken Stone I h s c Course. (lieviscd, Octo l r~r , r c ~ j j . )

1)s' Reconstrnction with I3roken Stone of Existing I'ELVC. ment io form B Ihse Course. (Revised, October. 1 q 3 3 . )

254 S ~ I l ' p l ~ and Delivery of Gravel (Kcvixi l , h u ~ i i s t , ! 144 Chain Fencing artl ll,.awil,i:

2 1 0 ' Telford linre Course.

14y), I ?+c Loc;ition of I'rotrrtion I'enc.ing (instruction). (Revised, 193? .)

\kLy, ltJ4,I). A I j o i A 1S7.5

\lotor Tra& Hy-pass r ) feet wide. \lotor Traffic l{y-pass with steel grid Lo feet wide.

(I<evised, August. I L J , ~ I , )

BRIDGES A N D CULVERTS. 1 A 1 St;intlanl Iiric1:c I-oading (gcncrai instruction). (1938.)

A 4~ Stanclarrl I3rirlge Loading (instruction for dead-end Dcvclolmiental Koads.) (Keviserl, 1038.)

18* Data for Ijridgc Design. (Revised, August. 1944.) o m p n y i n g Uridge or Clllvert Designs.

.A 26 \Vatcr\rny Diagram. (I<e\rise<l, r < ) q j . ) I 371 Watcrwny Calculations. (193%)

T Z L * Snrfacini: with Txr (Keviscrl, May, 1q4o.) ! 4 421 Boring (;car. 1 inches. 14.5' Sllrfacing \\.it11 I3itllnlen. (Revised, August, rcj4l' ) ,\ 44 Boring Gear, 3,$ inches. %* Rc-surfacing \villi Tzu (Itrv~.;ed. May, 104n.) 1 '\ 134: Rod Sounding :\pparatus. 'J4' Ite-surfacing x i t h IJitunicn. (Revised, July, I c i4m) I 2.5. I>tpc Colvcrts : ~ n d 1Ieadwalls (It <.,I, Dccc~nbcr, 1939)

2 . W Tar or Ijiturnen I'enctration hlacadani, Snrfacc I and drawings, Single Ro\vs o pr'. r i in. to '21 in. Course. 2 inches thick. (Revised, Decenibcr. 1g30.) dia. ( . \143* 1q3(1), r-.3 f t . cliti. ( . 4 1 3 ~ ~ , * 1~139),

Ob* Tar or Bitumen I'enetration hIacadam, Surfacc 1 3 f t . 6 in dia. (.A 172*), 4 f t . dia. (.A 173'). 4 ft . 6 in. roorsc, 3 inches thick. dia. (:\ 174) . j ft . dia.. (.A 175) . 0 f t . dia. (A 177);

nouhlc S < o w h of Pipcs. 15 i n to 1 1 in. dix. ( A 211.) Cross-scctiim .\ 1147 ( n h r ~ h , 1932). e-? f t . di;i. (11 2o3*, 1935), 3 it. (1 in. dia. ( A 215)

4 it. dia. ( A .ius), 4 ft. 6 in. dta ( A m j ) . 5 f t . dia. ( A 2n6), 6 f L . dia. (A z13) ; Treble I<ows of Pipes, 15 in. to Z I in. dia. (A Z I O ) , 2-3 ft . dia. ( A 216, 1936), and Strniglit Hradwalls for Pipe Culverts. 15-24 in.

(Revised. September. ~ 9 3 6 . ) 1 I '.i* Crlnent C'oncrctu I'tivcrncnt (.\pril, 1<,3g) and I'lan and

I GENERAL. 3.12' Cover Sliccl for Specifications, Council <~uotr<tt.i. ~

I (Revised, April, ~ i i j i j . )

(Lcevised, 1Iay. IC,.! j ) ! A I * Joint for Concrete Pipes. (Revised, August, 1933.) 2 4 ~ * Gencral Conditinns <,f Contract, Conncil Conir;lct. I dia. (.4 11.53*).

64' Schednle of Ouantitics. i h 142' Sidehill Inlet Sump (Rev i sd , July, r93n.) 30* Bulk Sum 1'Fndrr l:vrm, Coiiiicil Contract.

Dn* Hulk Slim C'ontrticl I : o n i ~ , Council Contract.

( R ~ ~ ~ ~ ~ , ~ I . j i

138* Pre-Cast Concrctc I3os Culvcrt (April , I YZ+<J) and draw- ings, < J in. high (.4 .+Xg*), I ? in (.\ 440*), I ft. 6 in (a 4+7*). L f t . (.I 44S*), 2 f t . 0 in. (.\ 4401.

A u ~ u s t . i<l4lL) l

arid instruction sheets ( A 3 0 5 , A 3jg, A 300, A 304).

.% I341 Timber Trestle and l3;irricr. 1 12 309% Concrete Culvert I'osts. (Revised, J u n e , 19.37.) A 1x24 Light Broom Drag. I 30" Pile Drivers, specification fcr 25 ft . , antl drawings for A I w 4 I'ipe Frame Drag. 5" f t . i?\ zog), 4" f t . (A ~ 5 3 ) , and 25 f t . portable

.\i.r;Lnjirmont of lhl t i i ig Planks for varions widths of .I 178 >kn~ld far Conc

-4 45 Timber Jjridge, r tandard Details. (Itcvised, March.

A l j S l j ..\ ,45.'-i)Trce Guards.

1'17' Hire 0 1 Council's I'l.~tit A 47X* Specimen Drawinxs. Knral Road Design, with drawinss

A 47.4,: Specimen Dnwinq , l;iiit Country Road Dusian. r h q Timhrr I3ram I5ridge (Kevised. Jllly. lq12) and in- A 1113' Rural Road l ' la i i ;ind Longitndinal Section I:orm I struction sheets. 16 ft. (A 7 1 ) , I S ft. (A OS), 20 f t

(A 70) and 2 2 f t . (.A 1 7 6 ~ ) . Amended Aug. 1946. A I 1 14' Rural Road Cross-srction liorin (tracing cloth). A 1131i and 4 ,165 Timher T.ow I.evnl Bridges, instruction .% l I l g * lJrban Road I ' l m l~ornis (tracing cloth). sheets for 1 6 fcct, and r8 fcct bctwccn kcrbs.

193 Duties of Slipcrintending Officer (instructioiis), ,\ 1222, A 1166, and A 1 2 2 3 Single Span Timbcr Culverts. span< 12 f t . , 18 ft., instruction sheets for ~h ft., 18 f t .

1 1 1'145 Stadm Reduction Diagram. and zu f t . betxvecn kerbs. 35.5' Instructions for Design of Two-lam Rural Highways ~ t q * Timber Culvcrt and drawings, 1 ft. 6 in. high (A 427).

A 148 j * Horizontal Curve Transitions (diagrams). A 1489.. A 1 4 8 S ~ * , A 1488~ ' . and A curve 326 Extermination of Termites in Timber Bridges. (Revised,

Transitions (tables for speeds of 30, 40, 50. and bo miles per how) .4 Z Z L * Pipc Handrailing Detail.. (Itevised, I'ebruary, 1938.

A 1614 \Videning of Shoulders on Crests. 350 Iteinfcrccd Concrete Bridge. (Revised, January, 1946.

(.\ "4".

dcck.

194' . ) (Revised, April, "137 )

h 47S.A' and .\ 4 7 x 1 ~ . I .4 1?<)1 Timber nealii Skew Bridge (Details).

( t r ac i i i~ clnt 1 1 ) . I

(Revised. July, 10.38.)

2 f t . (A 42s). 3 ft . (A 4 q ) , 4 f t . (A 430) . 5 f t . to 8 f t . ('937). high (-4 431).

October, I C J ~ O ) .

Slandarcls marked * may br, purchawd from t h c Govcmmrnt I'rinlrr S y d w y . O l h r r ~ may bc purchavcl lrnm t h e Head Ofice of the Drpartm-nt a f ' b i ~ i n Roads, j og CastlPrraph Strert, 5y~lncy. s1n;Ic CopCC5 bcing frre 1') C O U l c i l E

Y - I State Highway System

of the

State of New South Wales

I

Divisional Boundaries ... ---- Divisional Offices . . . . . . . 0

SCALE Area of New South Wales, 309,433 square miles.

MILEAGE OF ROADS CLASSIFIED UNDER THE MAIN ROADS ACT, AS A T 1st JULY, 1946.

FXI 0 5'3 100 150 '2000 Length of public roads within New South Wales. 126.058 miles. h - -

State Highways ........................... Trunk Roads .........................

..................... NORTHERN

TERRITUN Developmental Roads ................. --- WESTERN

25,663

2.193 UNCLASSIFIED ROADS, in Western part of State. coming

within t h e provisions of the Main Roads Act ............ TOTAL ... 2 r . m -

y p 1 4 S H W .