Millennium Bridge, London

330m above the Thames

The London Millennium Bridge is a 330 m pedestrian bridge, spanning the River Thames between St. Paul’s Cathedral and the new Tate Gallery. The winning design was awarded in 1996 after an international competition, to Ove Arup (Engineers), Foster & Partners (Architects) and sculptor Sir Anthony Caro.

At least 150,000 people used the bridge in the first three days of its opening weekend.

On Saturday June 10th 2000, a larger than expected movement of the bridge structure was recorded. In order to further investigate this problem, the bridge was closed on June 12th 2000 and a series of tests were developed.

Analyze bridge movements

Sixense was approached to measure the tilt of the mid-section of the bridge decking in two separate scenarios:

• bridge unloaded
• bridge loaded with pedestrians (120 people, standing in an area 120 m long x 2 m wide)

Our engineers had a time frame of only 20 minutes to record readings and register the final ‘load applied’ results.

Tilt was measured at 6 different bridge sections, firstly, whilst the structure was unloaded, and then after the pedestrians had been placed in the standing zones.

The two readings from each cross section indicated any lateral changes in tilt to the bridge deck.

The results were immediately entered into a spread sheet on site and the overall tilts were computed in less than 5 minutes.

The data was presented to the client in digital format on site and then faxed as an official copy the following day.