Evaluation of modeling strategies for gravity and lateral load analysis of confined masonry structures

Numerical models are effective tools for analysis and design of structures. However, their potential often falls short while simulating the behavior of masonry structures because of their complex anisotropic nature. This complexity increases further for confined masonry (CM), where the masonry walls are confined within reinforced concrete members. Though some modeling schemes have been developed for analysis of CM walls, their applicability and accuracy are a matter of contention as they are based on different assumptions. Most design codes do not specify modeling schemes for CM due to limited research. Further, the limited modeling choices have not been validated sufficiently posing difficulty for practicing engineers in adopting them. Therefore, past numerical models of CM were first reviewed in this study. Then, simplified models such as wide-column model, strut-and-tie model, equivalent truss model, equivalent shell/strut model, and vertical–diagonal strut model were utilized to conduct gravity and lateral load analyses of CM walls having different aspect ratios. The comparative assessment between different models showed the efficacy of some schemes while exhibiting the ineffectiveness of others. Results of the nonlinear pushover analysis showed the best fitting models for capturing the experimental response of CM walls. The applicability of different models was also assessed by analyzing a three-story CM building under static pushover analysis. Thus, the study clarifies the pros and cons of different modeling schemes and provides ways for choosing an appropriate model for structural analysis, especially for nonlinear analysis required for performance-based design of single- or multi-story CM structures.