Probabilistic seismic collapse and residual drift assessment of smart buildings equipped with shape memory alloy connections

Abstract

This paper probabilistically evaluates the seismic performance of the smart buildings equipped with newly developed shape memory alloy (SMA) connections. The smart structures of this study are those not only can control maximum interstory drifts approximately similar to conventional buildings but also can substantially reduce residual interstory drifts somehow that most of the nonlinear deformations are gathered in SMA fuse bolts. These smart buildings have low cost repair after moderate to severe earthquake events. Although “yielding” of steel structural elements is a design solution employed for dissipation of energy in structures and plastic deformation capacity of members is controlled by design codes for life safety performance level, the damage taken by deformed elements, corresponding residual drifts, and its economic loss after a serious seismic event is undeniable. In order to investigate the combined effects of SMA usage in smart structures including reduction of energy dissipation as a negative impact and removal of residual drift as a positive impact in comparison with conventional structures, superelastic SMA bolts are employed into the connections of two prevalent lateral load-resisting systems, i.e., moment-resisting frame (MRF) and eccentric braced frame (EBF). At first, proper configurations for the beam-column connections of MRFs and the link-beam connections of EBFs are selected from previous research works and validation of the finite element models of them are carried out. Then numerical models of the selected lateral load-resisting systems with and without SMA connections are developed using 4- and 8-story MRFs and EBFs of code-compliant NIST buildings (NIST Technical Note 1863-3). Afterwards, all the buildings are subjected to quasi-static cyclic loading and incremental dynamic analysis (IDA), so the power of employing SMA connections on seismic performance of the buildings would be investigated through seismic concepts. Based on the results, utilizing SMA connections in smart buildings not only could keep interstory drift control performance almost similar to conventional buildings but also could substantially reduce economic loss with significant control of unwanted residual deformations in structural fuses due to their unique ability of induced “recentering” behavior in structural performance. The results probabilistically determine the seismic performance acceptability of studied smart buildings based on the impact of key structural response parameters (i.e., maximum interstory drift, residual interstory drift, and energy dissipation) on the seismic performance of the structure.