THE DESIGNER of a new lightweight footbridge in Paris this week denied French press reports that it wobbles like London's Millennium Bridge.
Structural engineer Henry Bardsley said that the 270m long Simone de Beauvoir bridge over the Seine was expected to move under certain wind and pedestrian loading situations.
'This is a highly efficient, lightweight bridge with a main span of 190m. You would expect it to move, ' said Bardsley.
'The structure is intentionally flexible and reacts pleasantly to wind and pedestrian movement.
It behaves as we expected.'
He emphasised that excitation of the bridge had been anticipated early in scheme development and that it had been designed to be fitted with dampers on completion.
'We were lucky that our design period started before the construction of London's Millennium Bridge, but work did not start on site until quite a bit after. We were able to take on board information from the Millennium Bridge for the fine tuning of ours, before it went to tender [for construction].'
Bardsley said that the Paris bridge had been designed to be fitted with seven tuned mass dampers to control vertical and lateral oscillation.
These were fitted following completion of the bridge and after vibration testing had been carried out, 'to check that it conformed to our expectations'.
Bardsley said that the size and approximate mass of the dampers was specied before bids for construction were invited, allowing contractors to price them.
'We fine-tuned the specication following dynamic testing of the completed bridge, ' he said.