Glasgow City
Cable repair and replacement will take six months, say city officals.

After a cable failed and an anchor cracked on a Glaswegian arch bridge commissioned slightly more than two years ago, city officials ordered a shutdown for emergency repairs.

Heavy lifting equipment is scheduled to arrive at Glasgow's new Clyde River bridge this week to start replacing all its supporting cable connectors.

After just 28 months' service, one cable of the Finnieston arch bridge fell onto the deck last month and another anchor developed cracks.

Glasgow City Council has warned commuters that the $40-million crossing, known as the Clyde Arc, will likely be out of action for six months, says a spokesman.

The 160-m-long bridge incorporates a 96-m main span supported by seven pairs of cables hanging from an asymmetrical bowstring arch.

Cables are attached to the arch and deck with steelwork anchor forks, each weighing "several tonnes," says the city's spokesman. All the forks will be replaced.

One cable fell without warning at about 11:30 p.m. on January 14. There were no injuries. Repairmen temporarily replaced the cable. An anchor fault at a second cable emerged 10 days later, says the spokesman.

Though the bridge is designed to function with one cable missing, the city closed the crossing.

Camberley-based general contractor Edmund Nuttall Ltd. completed the crossing under a design/build contract in late 2006. London-based Halcrow Group is the lead designer. Macalloy Ltd., Sheffield, designed and supplied the cable system.

Macalloy's system is non-standard, tailored specifically to the bridge, confirms Chris Willett, the firm's sales director. "There are various investigations involving not just the product on various aspects," he adds.

While investigations into the failure continued, Nuttall began mobilizing barges, cranes and access equipment to replace all the cable anchors, says a company official.

From saddle-like frames on the arch, Nuttall will use strand jacks to de-stress each cable in turn and replace its end connectors.

Repair costs remain undisclosed, but are likely to be borne by Nuttall in the first instance. The bridge is still under its guarantee period, says the city spokesman.