REMOVAL OF the failed bearing which has immobilised Glasgow's troubled £8.5M Wing Tower since March has revealed no visible traces of corrosion damage, main contractor Carillion confirmed this week.
After waiting weeks for a suitable weather window (NCE 20 June), the 105m tall, 450t structure was jacked up almost 20mm last Friday. The massive thrust bearing, which normally sits at the bottom of a 15m deep pit and carries the entire weight of the tower, was finally removed on Monday.
Carillion operation manager David Smith told NCE on Tuesday that the failed bearing 'showed no evidence of excessive corrosion.' He added: 'We'll be lowering the tower back down onto temporary supports tomorrow, and there'll be a meeting of all parties on Friday to decide the next move.'
Designed to rotate through 360 0so that it always faces into the wind, the tower forms the focal point of the Glasgow Science Centre. When it was discovered that the entire structure had dropped 15mm the tower was closed and investigations began Originally it was assumed that water leaking into the basement pit since the tower opened last year had caused accelerated corrosion of the lower bearing. But the leaks were traced to cracks in the seals between the tower and the podium roof that encircles it. (NCE 14 March).
These were thought to have opened up as the tower sank, implying that the bearing failure was down to a design or manufacturing fault. But with the bearing invisible inside its housing, it was not until yesterday that the actual lack of corrosion discovered made this explanation more probable.