BergerWorld: 2nd Quarter 2008

Bear Mountain is an attractive toll suspension bridge in Upstate New York, carrying U.S. Highways 202 and 6, as well as the Appalachian Trail, across the Hudson River. When opened in 1924, it was the largest suspension bridge in the world, as well as the first suspension bridge to have a concrete deck. The construction methods pioneered in building it were adopted for the construction of several much larger projects, including the George Washington and Golden Gate Bridges.

A&W was retained to inspect the main cables and suspender ropes on the 687-meter-long Bear Mountain Bridge. The assignment involved evaluating the corrosion of the cables and suspender ropes and collecting wire samples for an analysis of the existing main cable. The Team also evaluated alternative concepts to restore the structural capacity of the bridge, including the addition of auxiliary cables to supplement existing cables and the complete replacement of the existing cables. Each alternative was then subjected to 3-D computer modeling and seismic and wind analyses. Upon the completion of alternative analyses, the complete replacement was selected. The work includes geotechnical and environmental studies, plans for maintenance of traffic during construction and the development of load transfer and erection methods.