Abstract

The Seismic design code of Canada is changing rapidly to accommodate the needs of the future generation of buildings for management of earthquake hazard mitigation. In this context the recent advancement in Earthquake Technology and Structural Engineering has emphasized on the need for a better methodology and in-depth investigation into the area of structural performance evaluation in order to ensure that structures designed for the areas of high and moderate seismic hazard to the expected standards and meet the objective of life safety and collapse prevention in a real life scenario. In order to ensure the above performance objectives for a building structure, it is necessary to estimate its capacity with respect to the demand, and the dynamic response corresponding to the design levels of earthquakes. The research carried out here aims to investigate: (i) the earthquake demand and capacity profiles of a set of set of moment frame buildings designed according to the latest version of the National Building Code of Canada, and (ii) the effect of scaling and spectral matching techniques commonly applied to ground motions on the seismic demand parameters determined using the dynamic time history analysis. A set of buildings with steel moment resisting frames of 5, 10, 15, 20 stories in height and located in Vancouver area of Canada have been considered in this study. An extensive review has been conducted to determine the existing methods for performance-based design and the techniques available to selecting and scaling suite of earthquake records to perform a fully non-linear dynamic analysis in time domain. Based on that, a range of scaling techniques including linear scaling techniques, and spectral matching technique have been considered for an ensemble of recorded ground motion time histories. In addition a set of artificially generated spectrum-compatible earthquake records are also considered. The static pushover analysis has been carried out and the corresponding capacity curves have been obtained and interpreted with commonly used performance-based design methods. It is observed that all the methods considered here confirm that the existing design based on the code procedure is adequate and conservative. The pushover curves are also compared to the results obtained from the Time history analysis to determine the performance achievements of the buildings. The interstory drift obtained from the time history analysis using different scaling methods show a uniform and consistent pattern of deformation in low rise to medium rise frames whereas dispersion greater dispersion of the results has been observed in tall buildings. Other response quantities such as the lateral drift, base shear and bending moment show similar patterns. Based on the results from the research it is suggested to use the artificial records if site specific real ground motion records are unavailable. The scope for further research lies in exploring ways to the possibility of new scaling techniques that can control the dispersion in the response more effectively