Question

Performance-based seismic design of shape memory alloyreinforced concrete bridge piers. I: development of performance-based damage states

Answer 1

Performance-based seismic design aims to dictate the structural performance in a predetermined fashion given the possible seismic hazard scenarios the structure is likely to experience. Identifying and assessing the probable performance is an integral part of performance-based design. Before implementation, accurate and practical definitions of different performance levels and corresponding limit states must be determined. This study aims to develop performance-based damage states for shape memory alloy (SMA)–reinforced concrete (RC) bridge piers considering different types of SMAs and seismic hazard scenarios. Using incremental dynamic analysis (IDA), this study develops quantitative damage states corresponding to different performance levels (cracking, yielding, and strength degradation) and specific probabilistic distributions for RC bridge piers reinforced with different types of SMAs. Based on an extensive numerical study, this study also proposes residual drift–based damage states for SMA-RC piers. Finally, an analytical expression is proposed to estimate the residual drift of SMA-reinforced concrete elements as a function of the expected maximum drift and superelastic strain of SMA. Comparison with experimental results revealed that the proposed equation could very well predict the residual drift obtained from the experimental results.