Engineers building the $1.74 billion Ting Kau bridge hope to make up a month's delay when work starts next week on the central 200-metre-high tower. Work on the 1.17 kilometre triple-tower structure between Tsing Yi Island and the New Territories has been held up by technical difficulties. 'The central island took longer to build than expected . . . It was difficult to compact the sand [which formed the four-hectare island] to the design requirements,' said Highways Department acting government engineer Eddie Roblin. Bridge builder Ting Kau Contractors has already clawed back about a month's delay after working 24 hours a day, seven days a week to finish the island. But there have also been difficulties reclaiming a small piece of land for the Tsing Yi tower. Problems emerged after the initial seawall design was changed to a more substantial horseshoe-shaped structure to prevent possible damage by ships. Massive steel struts have been fixed to brace a semicircular wall of girders which is being used to help support a permanent concrete wall. 'The contractors have worked very hard to get the job done,' Mr Roblin said. Ting Kau Contractors project director Domingos Azevedo said: 'We are fighting to meet our deadlines.'