Hybrid approach for simulating shear-flexure interaction in RC walls with nonlinear truss and fiber models

An alternative approach to the nonlinear truss model (NLT) is proposed to simulate the seismic behavior of reinforced concrete (RC) walls with various aspect ratios (ratio between the height and the length of the wall, h(w)/l(w)). The alternative consists of a hybrid model comprising an NLT panel connected in series with a forced-based fiber-beam-column model through a rigid elastic beam element (HyNLT-F model). The HyNLT-F approach saves computational time as compared to the default NLT model while keeping the capabilities of modeling inelastic shear response and shear-flexure interaction under static cyclic or dynamic loading. These capabilities are first validated for the default NLT model using the experimental test data of two RC-wall panels subjected to reversed cyclic loading, one whose response is flexure-dominated and another with a shear-predominant behavior. The numerically computed lateral force-displacement relationships, lateral displacement contributions, shear-flexure interaction, and vertical strain distribution at different levels of drift demand show a good agreement with the experimentally recorded responses. The hybrid alternative is then validated using three RC-wall panel experiments with high (h(w)/l(w) = 3.1), moderate (h(w)/l(w) = 2.3) and low aspect ratio (h(w)/l(w) = 1.5). The capabilities of the hybridization are evaluated at the global and local level of response, as well as in terms of computational time needed to run the model in comparison with the default NLT model. As an application, a HyNLT-F model is implemented in a multistory non-ductile RC frame-wall structure, to evaluate the impact of the nonlinear shear response at the critical section in the global structural behavior under static and dynamic loading. The results show that the HyNLT-F can model features of the wall response such as inelastic shear and shear-flexure interaction at the critical section, which of interest for certain structural typologies.