Comparative of single pendulum and triple pendulum seismic isolation bearings on the St. Laurent Bridge, Quebec, Canada

The St. Laurent Bridge, part of the new A30 highway in Quebec, is a low-level crossing over the St. Laurent River. This concrete structure supported on short stocky piers has been designed with seismic isolation to reduce the otherwise high seismic demand due to its support configuration. The seismic design compared the use of friction pendulum bearings in two of their modalities, single and triple pendulum, to determine which was most effective. In this particular case the single pendulum bearings performed slightly better, although the triple pendulum bearings were selected based on supplier price.