TWO BRIDGES

Ashburton Guardian, Volume 56, Issue 18, 2 November 1935, Page 3

TWO BRIDGES

MODERN STRUCTURES AT RAKAIA TWO-WAY ROAD TRAFFIC. TOTAL COST OVER £150,000. (Special to the “ Guardian.”) CHRISTCHURCH, This Day. It is likely that two new bridges will be erected over the Rakaia River within the next 18 months. Already the Railways Board has approved of plans for a new railway bridge to re* place the present one, and the Main Highways Board has practically readied a definite decision to span the same river with a new two-way traffic bridge alongside the railway bridge. The total cost of the two bridges will be more than £150,000.

Yesterday the General Manager of New Zealand Railways (Mr G. H. Mackley) told an interviewed in Wellington that the Railways IJoard had definitely decided that the erection of a new railway bridge over the Rakaia would be undertaken in the next financial year—l 936-37. The boards* had approved of tentative plans. The estimated cost of the new bridge was £85,000. It was not expected that the work would be completed before the end of next year.

Two-Way Bridge. ■ An official statement was also made about a new highway bridge over the Rakaia, proposed by the Main Highways Board. The Chief Public Works Engineer (Mr C. J. McKenzie) said that the board was considering the erection of the bridge, and had practically decided to go ahead with the proposal. A definite decision depended on the replies received from interested local authorities about the contributions they were prepared to make toward the cost of the bridge. It was expected that the total cost of conwould be between £60,000 and £70,000. st-rueting, a two - way traffic bridge Shorter Structure. When Mr McKenzie was asked about the negotiations which had been proceeding between the Highways Board and the Railways Board over a proposal that the board should buy the present railway bridge, he stated that the board had come to the decision that it would be a more economical proposal to build its own bridge. It would have been a matter of a very few years—had the board decided to purchase the present structure —. before the public would have been asking for a bettei one capable of carrying increased traffic. * At the same time the board had also to consider the high cost involved in redecking the present railway bridge.

The new bridge would be of reinforced concrete, and would he almost alongside the present railway bridge. It was possible that it would be somewhat shorter than the present bridge, and investigations were being made to this end. There was a likelihood that in constructing the bridge it would be possible to make the approaches much longer than those to the present railway bridge, and so shorten the distance of the actual bridging necessary. No details about the construction were yet available, Mr McKenzie said.

The Rakaia railway bridge is the longest in the Dominion, and the original portion of it was erected asHai back as 1871. The length was then 4500 feet, but in 1882 it was extended on the south side by 1440 feet, making a total length of 5940 feet. The structure is built entirely of wood.

Increase in Charge. In June, 1931, the railway Department announced its intention to increase the charge made against the Main Highways Board for the use o the bridge as a highway. It was stated at that time that the bridge was fast approaching the period when its use as a railway bridge would cease; the heavy trains which had passed ox ei it making it necessary to. erect a new structure in the neax* futuie. Early in 1932 the proposal for a new bridge was again put forward, and in January of that year the Public Works Department, on behalf of the Mam Highways Board, started a survey ol the riverbed to ascertain the length of a new bridge should it be decided to build one. It was stated that if a new bridge should be erected it would be a more substantial structure than the existing one. The Railway Department would need a powerful bridge to carry the heavy trains that would pass over it daily. It was stated at that time that any suggestion for a separate bridge for road traffic would he welcomed, as with the one bridge for both road and railway traffic, considerable .delay was often caused.

River Survey Completed. The survey Carried out by the Public Works Department was finished in March, 1933. It was then considered possible that the existing bridge would be handed over to the roading authorities for use as a public highway, and a new bridge erected to take the railway. The Department had collected data relating to the fall, flood level of the river, and the variation in width, to ascertain if a new bridge could be built shorter than the old one. In June of this year negotiations made for the sale of the bridge by the Railway Department to the Main Highways Board. In the event of a sale to the Main Highways Board it was proposed that a new railway bridge would be constructed, and the old bridge used solely for road traffic. It was stated a.t that time that negotiations had reached such a point that the Department was perfectly willing to sell the bridge provided a satisfactory price could bo obtained for it. The Railway Department was faced either with having to undertake considerable modification to the present structure, or with selling it and putting in a, new one a little further upstream. It was also reported by a railway official on this occasion that the bridge had always been kept in good repair and that it could be made to last for many years more for highway traffic.