Seismic Performance of Hybrid Self-Centering Braces with Structural and Nonstructural Damage Control Functions: Validation Tests, Computational Modeling, and Benefits Evaluation
Shuling Hu, Tong Guo, Yuji Koetaka, Zhi‐Peng Chen, Bin Wang, M. Shahria Alam, Songye Zhu
Abstract
This paper presents a comprehensive study of validation tests, computational modeling, and system-level benefits evaluation of an innovative hybrid self-centering brace (HSB) with structural and nonstructural damage control functions. The HSB is constructed by combining shape memory alloy (SMA) U-shaped dampers and rate-dependent viscoelastic dampers in parallel. Validation test results confirmed the desired rate-dependent hysteretic behavior under dynamic loadings. A new SMA material model was proposed and developed in OpenSees for modeling the hysteretic behavior of shape memory alloy U-shaped dampers. A new ViscoelasticDamper material model, based on the nine-element Maxwell model, was proposed and developed in OpenSees to capture the amplitude- and frequency-dependent hysteretic behavior of viscoelastic dampers associated with cyclic deterioration caused by peak deformation and hysteretic energy-dissipation. The computational model of HSBs was proposed by combining the newly developed SMA and ViscoelasticDamper material models, and the model was validated using the test results. Advanced steel frames using HSBs as the lateral force-resisting systems (denoted HSBFs) were designed. The benefits of HSBFs were investigated by comparing the peak and residual interstory drifts, absolute floor accelerations, and floor spectra of a six-story HSBF with those of another emerging SMA-based self-centering braced frame (SMABF) under earthquakes. The results confirm that the HSBF can achieve better performance than the SMABF in reducing base shear demands, absolute floor accelerations, and floor spectra, and they have comparable capacities in controlling peak and residual interstory drifts.