Daily Times

Sir: I have been assigned the task of doing structural surveys of some of the existing bridges in Karachi as part of my final year project in the civil engineering department of a reputed university. When I observed the bridges that pass over the Lyari stream and Gujjar nallah (drain), I was shocked to see their condition. Considering the chemical properties of fire and the adverse effects that it has on concrete, it was astonishing to note that garbage dumping and burning were being carried out under these bridges. Any civil engineer can point out that the action of fire on concrete may result in loss of bending or tensile strength, loss of bond strength, shear or torsional strength, compressive strength and spalling of the concrete.

At the bridge near Gulberg Chowrangi, the condition is even worse where the water-garbage swamp has risen so much that it has covered the whole bridge substructure, applying a lateral pressure on piers and substantially weakening the overall bridge structure. Cracks were observed in the pier piles of the bridge near Landikotal Chowrangi. Given this sorry state of affairs, another Shershah Bridge-like collapse is on the cards until the authorities concerned do not wake up from their deep slumber.

MIRZA IBRAHIM BAIG

NED University of Engineering & Technology

Karachi