In this paper, a performance-based seismic design (PBSD) of a CLT building was conducted and the seismic response of the CLT building was compared to that of a wood-frame structure tested during the NEESWood project. The results from the quasi-static tests on CLT walls performed at FPInnovations were used as input information for modelling of the CLT walls, the main lateral load resisting elements of the structure. Once the satisfactory design of the CLT mid-rise structure was established through PBSD, a force-based design was developed with varying R-factors and that design was compared to the PBSD result. In this way, suitable R-factors were calibrated so that they can yield equivalent seismic performance of the CLT building when designed using the traditional force-based design methods.
Based on the results of this study it is recommended that a value of Rd=2.5 and Ro=1.5 can be assigned for structures with symmetrical floor plans in the National Building Code of Canada (NBCC). In the US an R=4.3 can be used for symmetrical CLT structures designed according to ASCE 7. These values can be assigned provided that the design values for CLT walls considered (and implemented in the material design standards) are similar to the values determined in this study using the kinematics model developed that includes the influence of the hold-downs in the CLT wall resistance. Design of the CLT building with those R-factors using the equivalent static procedures in the US and Canada will result in the CLT building having similar seismic performance to that of the tested wood-frame NEESWood building, which had only minor non-structural damage during a rare earthquake event.
New Zealand Society for Earthquake Engineering Conference
April 13-15, 2012, Christchurch, New Zealand
The following paper presents the seismic performance of a two storey
post-tensioned Laminated Veneer Lumber (LVL) building during the aftershock sequence
following the MW 6.3 Canterbury earthquake that occurred on 22nd February 2011.
Composed of post-tensioned walls in one direction and post-tensioned frames in the
other, the structure under analysis was originally tested quasi-statically in the structural
laboratories of the University of Canterbury (UoC), Christchurch, New Zealand.
Following testing the building was demounted and reassembled as the offices of the STIC
(Structural Timber Innovation Company) research consortium on the UoC campus with
several significant changes being made to convert the building from its initial use as a test
specimen into a functioning office structure.