Transcript The Millennium Bridge, London.ppt

The Millennium Bridge,
London
Group 12
William Pender
David Coyle
Eugene Frindunbekov
Shane Fanning
Introduction
 First pedestrian
crossing in a decade
 Opened 10th June
2000
 Foster and Partners
 Arup Engineers
 100,000 people in first
hours
The Design
 “Blade of Light”
 Aluminium Lightweight
 Lateral Suspension
Bridge
 8 tensile cables
 Two props
 4m wide deck, joined
every 16m by
movement joints
Problems
 Oscillation and
swaying
 Larger amplitudes
than expected
 Bridge closed after
two days
So, what happened?
 Vertical force from
walking
 Slight force in
horizontal direction
 More pedestrians –
More Force
 Change in stride
 Force increases to
natural frequency
 Wobbly Bridge
Remedial Action
 Stiffen or Damping
 Active or Passive
Damping
 Viscous and Tuned
Mass Dampers
Summary
 Was Designed to specification
 Globally highlighted the problem with
light Bridges
 Because these problems were not
widely publicised and not well known
by bridge engineers at the time
 2 options for dynamic excitation