Naini Bridge
near Allahabad, over the Jumna River.
Also known as Jumna Bridge (Allahabad).
The Old Naini Bridge is a double-decked steel truss bridge which runs across the Yamuna (Jumna) river in the southern part of the city.
The bridge runs North-South across the Yamuna river connecting the city of Allahabad to its neighbourhood of Naini. It was built for the East Indian Railway. It is a double-decker road and railway bridge. The upper deck has a double track railway line which connects Naini Junction railway station to Allahabad Junction railway station, while the lower deck has been used as a road since 1927.
The bridge has fifteen spans of 205 feet each and three small openings of 30 feet and originally carried a cart road below. The piers are 60 feet above low water are founded on twelve brick wells each 13 feet 6 inches in diameter sunk to a depth of 42 feet below low water. The length of the bridge is 2,640 ft. Designed by A. M. and G. Rendel. Ironwork constructed at Canada Works, Birkenhead.
It was originally designed to be two parallel bridges on common piers, one for a double track railway, the other for a road. Initially only the railway bridge was constructed (see 1860s photo here).
The N-braced wrought iron girders had box-section compression members (the top chords). The tension in the bottom chords was taken by flat bars, generally 1" thick and about 15" deep. The number of bars varied from 11 down to 2, according to the distance from mid span. For William Humber's 1861 description and drawings, see here and here.
1865 Opened on August 15th.
Evidently the girders were replaced in 1928-9[1].
The main Naini Road Bridge is a modern cable-stayed bridge.