The piers were narrower and their cross-bracing was less extensive and robust than on previous similar designs by Bouch. There were other flaws beautiful disaster pdf download english detailed design, in maintenance, and in quality control of castings, all of which were, at least in part, Bouch’s responsibility. Bouch died within the year, with his reputation as an engineer ruined.
Did the Train strike the Girders? Construction began in 1871 of a bridge to be supported by brick piers resting on bedrock. Trial borings had shown the bedrock to lie at no great depth under the river. The bedrock actually lay much deeper than the trial borings had shown, and Bouch had to redesign the bridge, with fewer piers and correspondingly longer span girders. To reduce the weight these had to support, Bouch used open-lattice iron skeleton piers: each pier had multiple cast-iron columns taking the weight of the bridging girders.
Wrought iron horizontal braces and diagonal tiebars linked the columns in each pier to provide rigidity and stability. The basic concept was well known, but for the Tay Bridge, the pier dimensions were constrained by the caisson. For the higher portion of the bridge, there were 13 girder spans. In order to accommodate thermal expansion, at only 3 of their 14 piers was there a fixed connection from the pier to the girders. There were therefore 3 divisions of linked high girder spans, the spans in each division being structurally connected to each other, but not to neighbouring spans in other divisions.
The southern and central divisions were nearly level, but the northern division descended towards Dundee at gradients of up to 1 in 73. Gilkes, having first intended to produce all ironwork on Teesside, used a foundry at Wormit to produce the cast-iron components, and to carry out limited post-casting machining. 1880, but had begun liquidation in May 1879, before the disaster. 100,000 of Gilkes borrowings and been unable to extricate himself. The change in design increased cost and necessitated delay, intensified after two of the high girders fell when being lifted into place in February 1877. The first engine crossed the bridge in September, 1877. When again visiting the spot I should wish, if possible, to have an opportunity of observing the effects of high wind when a train of carriages is running over the bridge.