INVESTIGATION OF L-SHAPED LOW-RISE AND HIGH-RISE BUILDINGS RESPONSE TO NBCC 2005 AND 2010 SEISMIC LOADS

摘要

The current study builds on a previous study conducted by the authors that investigated the seismic provisions of the National Building Code of Canada (NBCC) 2005 and 2010, pertaining to the loading and analysis of irregular reshaped buildings. The study uses low-rise and high-rise L-shaped buildings as case studies. Three-dimensional finite element models of the two irregular L-shaped buildings were developed and discussed in the previous study. The lateral resisting system of the low-rise buildings consists of concrete shear walls, while the high-rise building consists of a combination of concrete shear walls and concrete rigid frames. Low and high-rise concrete buildings are modelled with the assumption of fully rigid floor diaphragms for computational efficiency. In the current the study, the effect of using rigid and semi-rigid diaphragms to simulate structural floors on the structure response to lateral loads is investigated. Significant change in the dynamic response and lateral force distribution along both buildings' height due to the use of semi-rigid diaphragms is noticed. In addition, a negligible contribution due to the effective inertia, due to cracking of concrete shear walls on the overall dynamic response of both buildings is observed. The study shows that the variation of post-cracking stiffness for concrete slabs significantly affect the stiffness and the natural frequency of the buildings.