THE OLD TAY BRIDGE.

Kumara Times, Issue 2072, 20 April 1883, Page 2

THE OLD TAY BRIDGE.

The old Tay bridge is, or was, the longest bridge in the .world over a tidal river. The original contracts for its erection were entered into on the Bth of May, 1871, but it was not until the 27th day of August, 1875, after all the preliminaries had been gone through, and the extensive and varied provisions made, both for the " housing" of the men and the preparing and working of the materials, that the first foundation was successfully floated out. The principal laid down at the commencement of the work—that all piers and girders were to be erected on the shore and floated out to their destination—was rigidly adhered to all throughout the carrying on of the work. In fact, no matter of what materials th<> parts were constructed—whether of iron obrick—they were finished on shore, ami floated out to their respective stations.

This will explain the cause of the length of time between the acceptance of the contract and the floating out of the first foundation. At its site the river is about two miles broad. The piers rest on rock at each end of the bridge, but the rock disappears as the niiddle of the river is reached. Fortunately, however, in the centre of the channel a stratum oi gravel some eighteen feet in depth is found, which is quite able to bear the weight put upon it, and the piers restin" have an extended base, which counterbalances any other defect. The entire length of the bridge is 10,612 feet, or two miles and fifty feet. It was supported by eighty-five piers, which supported eighty-seven spans of varying lengths. Over the part of the river which is generally used for navigation, thirteen spans, each 245 feet long were built, supported by piers so high that at the highest tide eightyeight feet of clear waterway was left. This height was also attainded by an arrangement which made the rails rest on the bottom of these spans, while over all the other spans the rails were placed on the top. These were known as the " High Girder Spans." The bridge was opened for traffic on the 31st May, 1878.