A study of some issues related to seismic design provisions of National Building Code of Canada

For the design of an earthquake-resistant structure one needs to know the characteristics of the structure under consideration and the seismicity of the region in which the structure is located. New knowledge on the seismicity of Canada and understanding of the structural behaviour under earthquakes have provided the motivation for significant changes in the existing provisions of the National Building Code of Canada (NBCC). This study is related to some of the new seismic design provisions being considered for the next revision of NBCC to be published in 2005. The study focuses on four different issues associated with the new provisions. The main objectives of the study are: (a) Development of representative values of the higher mode factor for different structural configurations, (b) Review of the NBCC 1995 code provisions procedure for distributing the base shear across the height, (c) Development of adjustment factors to be applied to the overturning moments obtained from the lateral forces determined by the NBCC 1995 distribution, (d) Study of the torsional behavior of single storey and multistorey building models of general class for a range of parameters and investigation of the applicability of single storey results to multistorey buildings, (e) Evaluation of the validity and limitations of the design eccentricity expressions proposed by Humar and Kumar (1998a, and 1998b) to general class of multistorey buildings and to suggest necessary modifications, if any, and (f) Assessment of the significance of P-Delta effect in a building subjected to earthquakes and development of a method to account for this effect.; This research also presents the results obtained from analytical studies conducted to study the elastic torsional response of a variety of asymmetric multistorey buildings of general class in which the ratios of torsional to translational stiffness vary significantly along the height of the building. Response spectrum dynamic analysis is carried out to obtain the exact response of the buildings. The results obtained from dynamic analysis are then compared to the results obtained according to design provisions proposed by Humar and Kumar (1998a). The dynamic analysis results are also compared to those of single storey buildings. (Abstract shortened by UMI.)...