Reinforcement for Bhairab Bridge

5 December 2001 09:23 - Royal BAM Group nv

On the bank of the River Meghna in Bangladesh, an enormous circular reinforcement cage has been prefabricated for one of the piers of the Bhairab Bridge, which is currently under construction. HBG's UK civil engineering company Nuttall is building this 1.2-kilometre fixed link around 80 kilometres north of the capital Dhaka.

The bridge, which is being built by the balanced cantilever method, stands on eight piers, five of which are being built within a circular cofferdam. The reinforcement cage, with a diameter of 20 metres, will be lowered around the six tubular steel pile casings, after which the under-water concrete footer can be poured. When the concrete has set, the cofferdam will be pumped dry. After placing the reinforcement, the lifting frame will be used as a tamping frame inside the cofferdam. The three other piers – the 'deepwater piers' – are being built using a 'jackable footer'. This method, which has been developed by HBG Civiel's engineering specialists Delta Marine Consultants, involves lowering a concrete footer – with part of the pier already constructed on it – down over the piles by means of jacks. Nuttall is due to hand over the project in the autumn of 2002. The contract value is almost £68 million.