RENEWAL OF LARGE-SPAN GIRDERS IN SOUTHERN INDIA. (INCLUDING PLATE AT BACK OF VOLUME)
Minutes of the Proceedings of the Institution of Civil Engineers
TIIE South Indian Railway Company has cnrriecl out during recent years a systematic renewal of all the girders on the main line of its metre-gauge system, renderecl necessary by rapidly developirlg traffic, and the consequent use of heavier types of engines. U p to 1911 no serious difficulties were encountered in the work, which had been confined to the renewal of plate-girder spnns of 70 feet and under; but on the northern sections of the main line there are a large number of bridges with
... f bridges with lattice girders of spans of 100, 130 and 150 feet which hacl to be renewed, and the problem of the best method of renewal of these had to be faced. The following is a description of the method adopted in renewing the eighteen spans of 120-foot girders over the Pn1a.r River. The old girders which were erected when the line was first constructed between 1876 and 1878 were of the Whipple-Murphy type with pin-connected joints, built by the Patent Shaft and hxletree Company, and were of a very light construction. These it was decided to replace by new girders having riveted connections and of much more rigid construction, being designed to conform with the l908 Standard Bridge Rules of the Government of India. Site.-The Palar River, in common with many of the rivers in Southern India, is for the greater part of the year usually a dry arid stretch of sand, but is liable to sudden floods, and then becomes a raging torrent in which only a structure built on very good foundatiorLs can stand. The problem therefore WRS to evolve a method the adoption of which would entail the least risk of damage to the new spans while being erected and inserted, and also one tl1a.t would muse the least interruption to traffic in the event of a flood. The bed of the river is fairly regular throughout its width, and slopes gradually from the north abutment to the soukh. Bed-stone level at the north end of the bridge is 21 feet above the river-bed, while at the south end i t is 25 feet. Downloaded by [ University of Liverpool] on [16/09/16].