Conditional Mean Spectra, Spectral Correlation Coefficients, and High Damping Spectral Amplitudes for Seismic Design and Evaluation in Canada

Seismic loads are a major source of threat against the integrity of structures in many parts of the world. In Canada, considerable contribution of ground motions to the forces acting on structures is expected in the eastern and western parts of the country where a number of major urban centers such as Montreal and Vancouver are located. This makes Eastern and Western Canada two zones of significant seismic risk. Thus attention has to be paid to the corresponding seismic risk when it comes to urban development and also maintenance and retrofit of the aging structures, particularly in these regions. As a result, seismic design codes and guidelines are constantly being updated to take account of advancements in technology and research. Prescriptions of these documents are mainly based on either direct studies of ground motions or the analyses and past experiences regarding structures and their analytical models. The recent versions of the National Building Code of Canada (NBCC) and the Canadian Highway Bridge Design Code (CHBDC), contain two major design tools which are directly developed from ground motions and their corresponding characteristics: Uniform Hazard Spectrum (UHS) and Damping Reduction Factors.