NEW BRIDGE.

Auckland Star, Volume LX, Issue 88, 15 April 1929, Page 9

NEW BRIDGE.

SPANNING THE WAIKATO

BIG RAILWAY WORK.

PLAN TOR NGARUAWAHIA.

CLOSE TO EXISTING BRIDGE

It has been decided to construct a new single track railway bridge over the T\aikato River at Ngaruawahia, 33 feet downstream from the present railway bridge. The n(*w bridge structure will not at first take the place of the bridge which was first opened for rail traffic on August 13, 1877, but will take the heavier trains and engines which increased traffic has warranted. lenders for tne hew bridge will close on July 29 this year, and will be called for in other parts of the British Empire as well as New Zealand. For some months testa have been carried out in the Waikato River bed alongside the present bridge, and these have proved entirely satisfactory. In view of the erection of the new structure instructions have been issued to the Auckland railways district engineer's staff to go ahead with preliminary work in order to clear the approaches. This labour will entail the removal of the bridgekecper's house, the present pumping house, and the filling in of the southern approach. A railway siding will also be put in on the north end prior to the contract being let.

The question of the disposal of the traffic bridge lias, as yet, not been settled; but when the new railway bridge 1s complete and ready for train-running, it is understood that the old traffic bridge will undergo repairs, and strengthening and provision for road traffic will be made over the present railway bridge. The matter, of future road traffic is being discussed by the Main Highways Board. Description of New Bridge. The new railway bridge will be one of six spans, tae three largest being 117 feet each, the centre one being high enough to allow all classes of river traffic to pass under it. There will ba two smaller spans of 38 feet each, and one of 24 feet, making a total length of 451 feet. The 38ft and 24ft spans will be constructed of plate girders and the 117 ft spans of steel Pratt trusses. No. 1 pier, on the "Auckland end, which will be constructed of solid concrete, will rest on 64 iron bark piles, each of which will be approximately 30 ft long. The second pier will consist of two reinforced concrete cylinders, the diameter of each being eight feet at the top and ten feet at the bottom. will b© founded on hard cemented shingle. The depth from rail level to the bottom of the cylinders will be approximately 70ft. The third pier will be similar to the second in its upper work; but it will be act on 50ft iron bark piles, there being 14 of these piles under each cylinder. Solid concrete will compose the fourth pier, and it will reston 74 piles of approximately 40ft, in lertgth. Pier No. 5 will also be, of solid concrete, resting on the Jfgaruawahia side of the bank of the abutment will fee similarly ppwistructtd. The upper-structure will, be of steel made, on the top and bottom lateral bracing system and - the only woodwork in the construction ot' the bridge will be th* railway steepfcrs.