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A dual structural system for low-to-medium-rise buildings is examined, comprising light-timber frames (LTF) coupled with a cross-laminated timber (CLT) wall. To enhance the energy-dissipating capacity of LTF featuring pinching behavior, friction sheathing-to-frame connections have been proposed in place of conventional nail connectors. The resulting friction LTFs (FLTF) exhibit sustainably rich hysteresis loops that significantly enhance energy dissipation capacity. Nevertheless, the friction-dissipating mechanism leads to nonuniform story drift distributions and residual drifts in multistory FLTF buildings. To address this issue, a CLT wall with self-centering hold-down connections is coupled to the multistory FLTF building for imposing uniform story drifts and for reducing residual drifts. A direct displacement-based design (DDBD) approach is employed to design the dual CLT-FLTF system and ensure (i.e., impose) uniform seismic demand across the height of the building. Nonlinear-time-history analysis (NTHA) and incremental dynamic analysis (IDA) show that the DDBD approach can lead to safe designs and effectively control the displacements of the proposed dual system. [ABSTRACT FROM AUTHOR]

The cross-laminated timber (CLT) shear-wall and glulam moment-resisting frame (CLTW–GMRF) dual system is a recently completed research prepared for the British Columbia (BC) Forestry Innovation Investment Ltd. With the introduction of new structural systems, the need to update existing building code becomes evident. Accordingly, this study evaluates the ductility-related force modification factor (Rd) of the CLTW–GMRF system for the National Building Code of Canada, utilizing the FEMA P-695 procedure. In two performance groups, 16 archetype buildings are designed considering different building storey heights, CLT shear-wall locations, and wall-frame moment proportions. Numerical model of the systems is developed in OpenSees and incremental dynamic analyses are conducted using 30 bi-directional ground motion records that represent the seismicity of Vancouver, BC, Canada. Collapse margin ratios are calculated to assess the adequacy of the trial Rd factors. The research determined that with an over-strength factor of 1.5, an Rd of 3 is found to be acceptable for the system. [ABSTRACT FROM AUTHOR]

A post-tensioned (PT) timber building coupled with dissipative bracing systems is a sustainable seismic-resistant structural system. This system combines desirable qualities of self-centering, energy dissipation, and lightweight timber, which attracts lesser seismic force and contributes to a better resilient system. Despite significant advancement in the provision of these sustainable seismic-resistant timber-based structural archetypes, more study is required to derive a fuller knowledge of the behaviour of these innovative structural systems under a range of ground motion intensities and limited state capacities. Direct displacement-based design, a performance-based design approach, is used for the design of this system, and performance assessment is carried out using nonlinear dynamic analysis. This study investigates the performance of the braced PT frame under different limit state considerations using ground motion records consistent with the NBC 2020 seismic hazard. [ABSTRACT FROM AUTHOR]

This study implements robust design optimization (RDO) of a self-centering viscous damper in the presence of seismic uncertainty. The RDO minimizes the effect of random input parameters on the output response, thus providing a robust solution. The optimal phenomenological parameters of the self-centering viscous damper are evaluated to ensure its robustness. The objective function of the RDO is cast as a sum of the mean and standard deviation of maximum floor acceleration and a constraint function of the inter-storey drift ratio of the floors. The mean component of the objective function minimizes the structural responses due to external loads, whereas the other component reduces the propagation of uncertainty from the input parameters. To reduce the computational cost of the RDO, a wavelet-based neural network is used as a surrogate model. The proposed optimization method is implemented in a 16-storey steel moment resisting frame with consideration of two ensembles of ground motions, i.e. far-field and near-field records, which are taken from FEMA P695 (ATC-63). To highlight the effectiveness of the proposed self-centering damper in mitigating maximum and residual drift ratios, two additional optimizations are undertaken using viscous and self-centering dampers. The numerical study shows that the neural network with a Gaussian wavelet function produces better accuracy compared to other wavelet functions. Also, the numerical analysis clearly elucidates the advantages of the proposed damper in reducing the residual drift of the floors over a viscous damper and a self-centering damper, which may lead to minimizing the post-earthquake economic losses. [ABSTRACT FROM AUTHOR]