Nonlinear numerical modeling approach and seismic mechanism analysis on new modular precast composite shear wall structure

An innovative modular precast composite shear wall structure with the advantages of modular precast con-struction and demountable ability was proposed, and its seismic performance was validated by shaking table tests. This study aims to develop a nonlinear numerical modeling approach for the innovative modular precast structure to promote its engineering application. An equivalent energy method for the overall backbone of the concrete constitutive relationship was derived to consider the concrete stiffness reduction in the numerical model. Based on sectional analysis and plane section assumption, an explicit equivalent joint model was developed to simulate the nonlinear behavior and failure process of the vertical joints. Comparisons between the numerical and test results validated the ability of the numerical model to capture both the global and local responses. More detailed results that were hardly obtained by tests, such as displacement components, joint mechanical state and gap opening behavior, were extracted from the numerical analysis to reveal the seismic mechanism of the modular precast structure. The dynamic analysis results showed that the vertical joint deformation induced 10% to 14% of the total inter-story displacement at the first floor within the maximum considered earthquake intensity. The equivalent joint model could simulate the failure process of individual screws which exhibited larger strains than those in shear walls. The gap opening behavior induced additional energy dissipation mechanism for the modular precast structure.