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Lansdowne Bridge Sukkur
Any vistor to Sukkur-Rohri Pakistan is usually awe struck by the largest man made monuments in the area. They are two in number. One is the 118 year old Lansdowne bridge and the other is the 45 year old Ayub Arch.
In the photo above, silver metallic structure is the Ayub Arch and the brown metallic structure is the historic Lansdowne bridge. This photo is dated July 25, 2007 and is courtesy of Raja Islam
Indus was bridged at Attock in 1887 and that allowed Railways in India to run from the Western most post of Khyber Pass to the eastern city of Calcutta.
India's rail link to the port of Karachi was however, still broken at the Indus flowing between the towns of Rohri and Sukkur. Indus was not bridged between Kotri and Hyderabad either therefore trains ran on Karachi-Jamshoro-Larkana-Sukkur route as early as 1879 and then they were ferried across to Rohri and vice versa on a river ferry.
At Sukkur the river Indus flows through a gap in a range of low limestone hills and gets divided into two channels (Sukkur and Rohri channels) by an island called Bukkur. The Bukkur island thus provides the best spot for a river crossing. See photo to the left, which shows two river channels between Sukkur and Rohri.
The river channel between Sukkur and Bukkur got bridged by 1885. The river bottom here is rocky so it provided solid foundations for masonry piers. This bridge got completed with three girder spans of 90, 230 and 270 feet. A 2007 photo of this bridge can be seen here.
Bridging the channel between Bukkur and Rohri was not so easy. The river bed here is not rocky but silty which made it difficult to build a bridge pier. Therefore bridge designs were put forward to build a bridge without a pillar. One such design was for an arched bridge but it was not considered in 1870s. Interestingly later on in 1962 the river was bridged using a very similar design that came to be known as the Ayub Arch.
Between 1872 and 1882 bridge survey was conducted and different people suggested 5 different bridge proposals. None of them was considered completely feasible at that time. An engineer by the name of Sir Alexander Rendel was then called in and he proposed a design consisting of two anchored cantilevers, each 310 feet long, carrying a suspended span of 200 ft in the middle. Interestingly, this design was considered feasible and later came to be known as the Lansdowne Bridge.
The girderwork of this bridge was given to Westwood, Baillie & Co. of London.
The bridge was first put together in the contractor's yard. The 170 feet tall cantilevers of the bridge when assembled, made quite a conspicious scene in London.
By 1887 the steel work started to arrive at Sukkur and Rohri. The bridge construction was then started under the supervision of F.E. Robertson and Hecquet. Their names are written to date on a plaque on each cantilever of the bridge.
The construction of Lansdowne bridge was no joke. It is said that bridge designer didn't thought much about how the bridge would be built in real life. Giant derricks, each weighing 240 tons and each being 230 feet in length had to be erected leaning out over the water and at the same time they had to incline inwards in the plane at right-angles to the line of the bridge. And as if that was not difficult enough, horizontal tie girders 123 feet long and weighing 86 tons each had to be assembled at a height of 180 feet. This indeed was a challenge in 1880s.
When both cantilevers were completed, work started on the center span. The bridge designer had intended that 200 ft long span would be assembled on boats and then hoisted up.
This plan did not work in practical as Indus remained quite violent 6 months of the year owing to floods. In the end Robertson built another temporary bridge to provide a platform on which the suspended span could be put together. This temporary staging wieghed 56 tons. The permanent girderwork of the 200 ft span was erected and riveted in four and a half days. This is a good going even with today's standards. In 1880s Robertson's men didn't have pneumatic tools or electric drives.
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