Description
The incorporation of Super-elastic (SE) Shape Memory Alloys (SMAs), such as Nitinol, presents a method of passively improving the damage resiliency of traditional reinforced concrete structural elements. This resiliency can be of particular use in seismic applications owing to the super-elastic behavior allowing for increased recentering. Currently available experimental data on hybrid slender shear walls incorporating both steel and SE-SMAs has demonstrated the recentering improvements while also highlighting that use of SE-SMAs tend to cause formation of a predominant crack that controls the response. The ability to more accurately predict this behaviour through numerical methods would allow for better understanding of nuances in hybrid slender shear wall design going forward. The paper herein presents a numerical modelling program that considered the impacts of local stress concentrations as a result of a singular predominant crack formation during reverse-cyclic loading. This modelling program was carried out in VecTor2, a non-linear two-dimensional finite element program, in conjecture with experimental data of a hybrid steel-SMA slender shear wall and a traditional reinforced concrete companion wall. The use of a strain-hardening reinforcement constitutive model which considered local fracture was found to improve the displacement prediction capabilities of models. Additional considerations which were investigated included increasing reinforcement properties to reflect conditions at the wall base and accounting for the impact strain gauge instrumentation may have on rupture of reinforcement. The results can provide insight into the creation of numerical models that better reflect the local stress and reinforcement conditions found in the presented hybrid steel-SMA and reinforced concrete slender shear walls.
