Evaluation of the seismic response coefficient introduced in the Canadian Highway Bridge Design Code

This paper describes results from an evaluation study of the elastic seismic response coefficient introduced in the Canadian Highway Bridge Design Code. The evaluation is conducted by comparing the seismic response coefficient with (i) uniform hazard spectra for selected cities in eastern and western Canada, (ii) spectra of numerically simulated ground motions for sites in British Columbia for scenario earthquakes on the Cascadia subduction zone, (iii) spectra of the 1988 Saguenay, Quebec, earthquake records and selected ensembles of recorded accelerograms from strong earthquakes around the world, and (iv) bridge design spectra of other countries. The results from this study show that the seismic response coefficient of the Canadian Highway Bridge Design Code is conservative in terms of the Canadian seismic hazard, with the exception of (i) sites close to the Cascadia subduction zone and (ii) sites for which the seismic hazard is governed by the effects of strong earthquakes at large epicentral distances. Key words: seismic, response, coefficient, acceleration, spectra, bridge, design, code.