KARACHI HARBOUR-EAST WHARVES, RECONSTRUCTION OF QUAYS.

Abstract

Thirteen deep-water berths and one shallower berth, aggregating in length 6,772 ft, were rebuilt on the eastern side of Karachi Harbour between 1955 and 1960 to replace open piled structures which, after a life of over 50 years, had suffered serious and extensive deterioration. The new berths were constructed in concrete, with a closed berthing face set forwarfdr om the old line, and backfilled with sand. The main structural members in the face are large I-section prestressed concrete pile units weighing about 50 tons each. These were placed at 9 ft 2 in. centres inside a steel cylinder which was subsequently jacked out against the piles. A special item of floating plant was used and the system enabled a range of loadings to be transmitted to the piles. Curtain slabs were inserted between the piles and provision was made to ensure a positive bearinogn the pile flanges. A substantial concrete capping beam cast on to the heads of the piles was anchored at intervals of 32 ft by high-tensile steel cables to individual concrete monoliths. Stressing of the cable ties in stages as the filling proceeded allowed a measure to be made of the forward thrust of the filling; the final stressing mobilized the resistance of the anchor monolith and establishedi ts adequacy.