Client: American Bridge/Surespan Joint Venture

Location: Vancouver, British Columbia

Klohn Crippen Berger Ltd. was retained by American Bridge/Surespan Joint Venture to provide a design-build seismic retrofit for the north approach viaduct of Vancouver’s signature Lions Gate Bridge. The north approach viaduct is the world’s first major structure to receive a seismic retrofit using the design-build contract format.

Klohn Crippen Berger Ltd.’s innovative and economical retrofit strategy was to dissipate energy by allowing the braced steel support bents to rock by uplifting at the baseplate level. This approach was taken as a means of limiting the loads on the steel structure. Explicit time history modeling was used to account for impact, rocking and other non-linear response characteristics of the retrofit structure. The final retrofit included strengthening of the superstructure, bracing, addition of concrete tie beams between footings, and the placement of pile in locations where large liquefaction-induced displacements were anticipated.

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