LONDON'S INFAMOUS 'wobbly bridge' is still on target to be stabilised 'this year' despite the late delivery of key components, engineer Arup claimed this week.
High tech US-made viscous dampers to be fitted under the deck and between the suspension cables at the piers had still not arrived on site as NCE went to press. Arup has always refused to be drawn over exact delivery dates of these units, which are key to the £5M retrofit.
(NCE 25 January).
However, recent public statements have promised delivery 'in the summer'. Arup now argues this includes September.
Project director Roger Ridsdill Smith said this week that he was confident the 37 dampers would arrive this month and be installed in time for the bridge to reopen before the end of 2001.
'To be sure of getting them on time we actually began procuring them before we started the prototype trials last autumn, ' said Ridsdill Smith. The critical operation, the firm maintains, was installation of the steel 'chevron braces' under the deck, which will operate the dampers. Fitting the dampers themselves is claimed to be relatively straightforward.
Installation of 29 pairs of German-made tuned mass dampers has begun from the northern end of the £18M crossing. Main contractor Cleveland Bridge is lifting the 2t units onto the deck at the southern end and moving them into position with a manhauled trolley. Most of these dampers will help prevent excess vertical oscillations, with only four pairs at the middle of the centre span preventing horizontal sway.
Ridsdill Smith confirmed that final adjustment of the damping will be a tricky process but added: 'We've been doing a lot of work on the settings and are confident it will go smoothly.'