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section of the Hawkerhury River to Mount While Toll \\'ay .I U S E I 9 6 6 Life is a matter of Ninety Miles of Bridge The New Roseville Bridgc , , .. .. .. .. 98 Construction of Expressways in New South Wales .. ._ 105 Tourist Roads-To Burrinjuck Dam and to West Head .... 107 Techniques of Modern Road Construction .... .. ,. 110 Warringah Expressway .. .. .. .. .. ,. 114 Royal Easter Show, 1966 . .. .. .. .. .. 116 Nepean River Bridges near Penrith .... .. .. ., 117 Sydney Harbour Bridge Account , . .. .. .. .. 120 General Aspects of Expressway Lighting . .. .. .. I21 Main Roads Fund . .. .. .. .. .. .. 123 Three New Country Bridges .... .. .. .. .. 124 Tenders Accepted by Department of Main Roads .... .. 127 Tenders Accepted by Councils .. .. .. .. _. 128 Main Roads Standard Specifications .. Inside hack cover COVER SHEET An aerial view of the new Roseville Bridge. The overpass at Mslga Avenue is in the foremound MAIN ROADS JUNE 1966 Ninety Miles of Bridges Major bridges have recently been cornpletcd over the Orara River near Grafton, the Great Ana Branch of the Darling River near Wentworth, the Murray River at Barmah and Middle Harbour at Roseville, adding further links in the chain of modern bridges over the State’s harbour and river JOURNAL or THE systems. DEPARTMtNT OF MAIN ROADS The extent of these great waterways and the enormous task of adequately bridging them can be gauged by the fact that there are approximately 500,000 NEW SOUTH WALES feet or about 90 miles of bridges on Main Roads in New South Wales. New South Wales, measuring an average 650 miles from east to west and 500 miles from north to south is three times the size of Victoria and about twice the size of the State of California, one of the largest of the United States of America. Broadly, the topography of New South Wales comprises four belts of Issued quarterlv by (he dis-similar country each running roughly parallel to the coast. There is Commissioner for Main Roads, the coastal fringe, a region of rupged hill country interspersed with fertile plains and river flats, next comes a belt of tablelands beyond which are the J. A. L. Shaw, C.B.E., D.S.O., BE. slopes and finally the vast inland plains which occupy one half of the State. Throughout the whole there is a complex system of rivers and streams. Rivers that rise on the eastern side of the tablelands flow to the sea and are subject to tidal influence. Those that rise on the western slopes flow across the inland plains merging into the great Murray-Darling river system. In the early days of the colony the most favoured method of transport was by water. It was the cheapest and swiftest. As a result the colonists travelled as far as possible by water. Small community settlements, which subsequently grew into country towns developed on coastal and inland rivers and travel was by road only when it could not be made by water and the only movement overland was on foot and with drays and waggons. Additional copies of this journal may be The earliest roads were generally connections between one river system obtained from or community and another. In the latter part of the nineteenth century and the early part of the Department of Main Roads twentieth century, the Public Works Department, the authority then responsible for roads, embarked upon a considerable programme of building 309 Castlereagh Street bridges and provision of ferries at river crossings. These bridges were designed to meet the needs of traffic at the time but completely inadequate Sydney, New South Wales for present day traffic. In post war years, the Department of Main Roads has followed a vigorous policy of replacing these narrow bridges and ferries. Australia Approximately 120 bridges are being built each year, many of which eliminate the old structures that have outlived their usefulness. The great waterway system of the State demands a very high price in providing communications. This is particularly significant in the Sydney Metropolitan area. Sydney can be justifiably proud of its beautiful harbour with its inlets and rivrrs providing a near perfect setting for a city and its PRlCS environs. Many cities of world renown have spent fortunes in artificially Thirty Cents providing the beauty with which our State capital is naturally endowed. However the price to be paid for this natural asset is enormous. With ever-increasing population and traffic volumes, these waterways have to be crossed to provide road communication between city and suburbs and between city and country-and bridges are very expensive items digging deeply into financial resources. ANNUAL SUHSCRIPTION Apart from all the bridges which have already been built, either as new One Dollar Twenty Ccnts crossings or in replacement of old crossings, many more have yet to be built. De Burgh’s Bridge over the Lane Cove River is being replaced, a Povt Free new crossing is now under construction over the Parramatta River at Camellia, a new bridge over George’s River at Alfords Point is planned, another major bridge is planned to carry the Warringah Expressway over Middle Harbour, twins to bridges at Iron Cove, Ryde and Tom Ugly’s Point will be required. More crossings of the Parramatta, Georges and Lane Cove Rivers and their tributaries will no doubt be required with the continuing expansion of the population to outer suburbs. Editors are invited to use any information contained in this Journal, And this tremendous programme for bridge building is repeated through- unless specially indicated out the length and breadth of the State. to the contrary; Notwithstanding all this, the less glamorous but no less essential road- black and white photographs will be made works to provide connections between these vital crossings must be provided available on request at the same time C 14280-2 The New 3oseville Bridge PLAN ROSEVILLE BRIDGE The Premier of New South Wales, the Hon. R. W.Askin, M.L.A., ojicially opened the new Roseville Bridge over Middle Harbour on Saturday, 2nd April, 1966. ITH the opening to traffic of the new bridge and vehicular traffic, three in each direction, a median, and W its approach roads, a new era in travelling con- a footway, six feet wide, on the upstream side. ditions is provided for motorists using the new facilities. Gone are the frustrating delays previously experienced The bridge is founded on sandstone or good quality on the old narrow bridge and the steep winding approach shale, partly by means of spread footings and partly by on the Roseville side. Instead motorists travel over the bored piles. The six river piers are each set on nine approaches and across the new bridge on a wide sweeping bored piles of 33 inches diameter drilled six feet into curve. sound rock. The other piers and the two abutments are set directly into the solid rock. The bored piles were constructed by driving steel casings to the surface of the NEW BRlDGE rock, excavating the soft material and then drilling the THE appropriate distance into the rock. The length of the longest pile is 94 feet. After placing a steel reinforce- Engineers of the Department of Main Roads designed ment cage the piles were concreted using the intrusion- the new bridge which incorporates the most modern grouting process, which involves filling the steel casing practices of prestressed concrete construction, taking with 2+ in. to 1% in. shortgraded blue metal and then advantage, architecturally, of a particularly scenic pumping in a cement grout with appropriate admixtures location. The slim superstructure stands high above to fill the voids. The pile caps have been formed inside the water and blends artistically with the steep slopes of precast skirting units which mask the piles to below the the harbour foreshores. level of the lowest tide. For both architectural and practical reasons, the skirting units and tops of pile caps The entire length of the bridge, 1,229 feet on the road are of dark concrete. Spread footings are set generally centreline, is situated on an under vertical curve, 1,600 a minimum of one foot into sound rock. feet long, between approach grades of 10 per cent on the southern (Roseville) shore and 4.2 per cent on the The piers are formed of three slender columns, the immediate northern (Forestville) shore. The deck is longest (at Pier 4) being 75 feet. In the case of the first 78 feet wide overall accommodating six lanes for three piers from each end the columns were cast in place I while columns in the other eight piers consist of pre- cast box-shaped units. The precast boxes are secured in each column by fourteen high tensile steel bars I& in. diameter. Each bar is anchored with a force of 55 tons. The column boxes were made by the contractor in a casting yard established upstream from the bridge site. After erection the boxes wcre filled with concrete. The columns are set separately on footings into the rock or (in the case of piers and piles) are attached to the pile caps. Conventional abutments have not been used for architectural reasons. At both ends the bridge termin- ates on a retaining wall running gencrally along a contour. On the Roseville end the wall is tied back by counterforts to an anchor beam set under the filling about 24 feet back from the abutment facc. On the Forestville side the wall. is tied to the rock by 26 high tcnsile steel bars 4 in. diameter. Each bar is anchored with a force of 27 tons. The superstructure essentially is a slab formed by prestressed post-tensioned beams resting directly on top of the columns.

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