Professor of Engineering, University of British Columbia
Seismic Performance of Timber Buildings
Carlos E. Ventura, Yuxin Pan and Armin Bebamzadeh
Department of Civil Engineering, The University of British Columbia, Vancouver, BC. Canada
A study on the performance of timber buildings under long duration earthquakes is discussed in this presentation. The primary objective of this study is to quantify the effects of long duration ground shaking on wood structures compared to short duration shaking. The investigation is confined to conventional low-rise and modern mid-rise woodframe buildings. The results of shake table tests of full scale models of benchmark structures are used for this investigation. Three-dimensional numerical models of the structures were developed using the Timber3D program and validated with the shake table test data. To isolate the effects of duration, two sets of short and long duration records that had approximately the same response spectra were used for nonlinear dynamic analyses of the model structures. Their collapse capacity was evaluated using fragility curves developed by incremental dynamic analysis. The results showed the collapse rate increased under long duration shaking due to a large number of inelastic cycles and higher cumulative energy demands that timber structures experienced compare with the short duration motions. The reduction in median collapse capacity for the low-rise wood structure with engineered oriented strand board sheathing and stucco was 26%, for the same structure but without stucco was 29%, and for structure with horizontal board sheathings was 61%, respectively. The reduction in median collapse capacity for the mid-rise woodframe structure was 18%. These results suggest that current design practice based on the response spectra analysis may not adequately characterize the potential collapse of timber buildings. This study highlights the need to include ground motion duration effects into current seismic design and assessment provisions.
Dr. Carlos Ventura is a Civil Engineer with specializations in structural dynamics and earthquake engineering. He has been a faculty member of the Department of Civil Engineering at the University of British Columbia (UBC) in Canada since 1992. He is currently the Director of the Earthquake Engineering Research Facility (EERF) at UBC, and is the author of more than 500 papers and reports on earthquake engineering, structural dynamics and modal testing. Dr. Ventura has conducted research about earthquakes and structural dynamics for more than thirty years. Three of his most significant contributions in recent years are the development and implementation of performance-based design methods for seismic retrofit of low rise school buildings, a unique seismic structural health monitoring program for bridges in BC, known as the BCSIMS project, and the first network-based earthquake early warning system for schools and public institutions in BC. These projects have contributed in a very significant manner to the seismic risk reduction efforts in BC. In addition to his academic activities, Dr. Ventura is a recognized international consultant on structural vibrations and safety of large Civil Engineering structures. The quality of his research work has been recognized by several national and international awards, as well as being appointed as member of the Canadian Academy of Engineering and of the Engineering Institute of Canada, and Fellow of Engineers Canada. He is also a member of several national and international professional societies, advisory committees and several building and bridge code committees.