THE WAITAKI BRIDGE.

Evening Star, Volume IX, Issue 2665, 1 September 1871, Page 2

THE WAITAKI BRIDGE.

The above work is referred to Acting Engineer-iu-Chief’s recent report to the Minister of Public Works, in the following terms:— The several sites available were inspected, cross sections of the rivor were taken, and other necessary information obtained, enabling the commissioners to arrive at the conclusion, in which I concurred, that, of the three sites proposed, the one lowest down the river was the best. This js about two and a-lpdf mijcs from tlje coast, and corresponds very nearly with tiro line of telegraph. The length of bridging required on the different sites was, on the upper, 4276 feet; middle, 6930; lower, 3,630 feet.

The latter, besides being so much shorter than the others, possesses features much more favorable for the erection of a bridge, and is on the direct and shortest line that can well be laid off for the railway. A full report and estimate of the cost of railway and bridges on the different sites was furnished by the Commissioners, who, in concluding their report, recommended that after every information had been obt lined as to the site chosen, plans of it should be sent to England, for the purpose of obtaining a correct plan and estimate for an iron bridge. This plan of action, it was thought, after due consideration, would lead to much delay, iandjthat it would be better, impossible, to order the necessary ironwork at once. The Commissioners were therefore invited to state the'.r opinion as to the shortest spans that could safely be used on the river, with the view of adapting to it the same style of bridge then being erected on the Great Northern Railway to Raugiora, viz., that of strong, plain wrought-iron girders, resting on piers consisting of a scries of hard-wood piles ; these being situated at a constant distance of 33 feet apart. The opinion being found to be unanimous that such a bridge might bo built over the Waitaki, plans were accordingly prepared in accordance with the provisions of the Railway Act, viz., that this bridge should be built to suit both ordinary and railway traffic. For this purpose the design included three lines of iron girders—two of them placed tolerably close together to carry the railway, and the third, with one of the former, to carry the ordinary traffic. The design being approved, orders were prepared and sent to England for girders sufficient to carry the ordinary traffic in the first instance. This required 220 girders, of 33 feet each, sufficient for 110 spans, or a total of 3630 feet. Plans and specifications are now being prepared for the supply of the necessary timber and the erection of tho piers and bridge, anticipatory of the arrival of the girders from England. Borings have been made on the proposed site, with a favorable result, to depths varying from seventeen and a half to twenty-eight feet. I may explain here that Mr Millar, in connection with the survey of the Moeraki and Waitaki line of railway, found it necessary, after frequent and careful observation of the river and its banks, to modify slightly the line originally proposed by the Commissioners ; and he has reported on his reasons for so doing. These have been laid before the Commissioners for their consideration and approval.