Golden Gate Bridge Seismic Upgrade
The BEAR Team was invited to participate in the Golden Gate Bridge Seismic Upgrading. The efforts included calculations of the newly designed dampening device which is pictures below. This project won the Outstanding Civil Engineering Achievement Award.
The Golden Gate Bridge opened to traffic in 1937 and has become recognizable around the world. The towers that support the bridge's suspension cables are smaller at the top than at the base, emphasizing the the tower height of 500 feet above the roadway. The Golden Gate Bridge's main suspension span is 4,200 foot long. The five lanes cross the Golden Gate Strait.
Joseph Strauss was the Chief Engineer in charge of overall design and construction of the bridge project and famed bridge designer Leon Misseiff was theprincipal engineer who produced the basic structural design, introducing his "deflection theory" by which a thin, flexible roadway would flex in the wind, greatly reducing stress by transmitting forces via suspension cable to the bridge tower.
Wind and earthquakes can lead to unexpected resonance mode which could cause the bridge to snap. When the Golden Gate Bridge District started a program to retrofit the Golden Gate bridge to better resist seismic events, the BEAR Engineering Team, headed by Dr. Glen Stevick was asked to do the calculations for the disk that was insperted as a damping device (see photo). For this work, Dr. Stevick received the Outstanding Civil Engineering Achievement Award in 2007.