WORK TO SAVE CAISSON

Press, Volume XCV, Issue 28270, 7 May 1957, Page 13

WORK TO SAVE CAISSON

Immediate Danger Seems Over’ (New Zealand Press Association) AUCKLAND. May 6. Men working 40ft underwater are thought to have won their battle to save the 1600-ton Auckland harbour bridge caisson from capsizing. Crouched in a compressed-air chamber inside the caisson, the men toiled desperately today *to remove silt and mud and enable the huge steel-and-concrete box to right itself. The caisson, which will form the foundation for one of the bridge’s piers, tilted to an alarming 30deg on Saturday. A sudden subsidence of the harbour bed under one of the cutting edges is believed to have been the cause. One side of the caisson, which is 600 ft out in the harbour from the southern anchorage at Westhaven, is buried 10ft deep in mud. and 400 cubic yards of mud clogging the compression chamber is being removed a bucketful at a time. There was room for only one man at a time at the bottom of the ladder leading into the chamber today. Because of added danger at low tide, the men worked only two hours either side of high tide yesterday. High tide gives the caisson buoyancy and added stability. Underwater surveys have been made by divers, and the project supervisor (Mr W. Cardno) said tonight that his engineers had calculated the centre of gravity and closely estimated the risks involved. It seemed that the immediate danger was over, he said, but it might be a week or more before this could be stated with certainty.