Sayed Mohammed Sayed

Investigating the nonlinear behavior of reinforced concrete (RC) elements was the objective of many experimental and numerical studies. This work briefly presents the previous work done in support of modeling reinforced concrete (RC) elements to evaluate their structural behavior. Modeling RC elements requires reliable nonlinear models for their inelastic positions under high loading. These positions are conformed as concentrated plasticity. For simulating RC frames, the concentrated plasticity was used in many studies to provide simple modeling with low computation cost. The concentrated plasticity is modeled using lumped plastic hinges (PH). Four PH types (flexural, shear, torsion, and beam–column joint) are defined based on the loading type subjected to the frame element. Consequently, it reviews the previous studies that modeling procedures for the nonlinear behavior of four PH types. The flexural PH, Shear PH, torsional PH, and beam-column joints could be defined, respectively, using empirical length, the approach of Watanabe & Lee (1998), rigid–element, and bilinear torsion–rotation behavior.

The structural behavior prediction of the multistory reinforced concrete (RC) buildings with masonry infill walls (MIWs) during earthquakes is challenging. This paper presents a nonlinear macromodeling strategy seeking a simple, reliable, and low-cost computational analysis of the multistory RC buildings that comprise MIWs, and that use frames or shear walls (SWs) for resisting the lateral load. The strategy employed four plastic hinge (PH) models for tracking the deformations (flexural, shear, and torsion) of the frame elements and joints, a multilinear plastic link for modeling the MIW, and a nonlinear multilayer shell element for modeling the SW. A flexural PH model characterized by discretization into fibers, a recommended position, and an iterative estimating for the PH length using a distinct formula for each loading level was proposed. This strategy was validated through eleven macromodels investigating four bare frames, four MIWs frames, and a SW where the average ultimate lateral load error was 9.2%, 3.6%, and 0.4%, respectively. Finally, the structural behavior of real ten-story buildings with/without MIWs was investigated. The results showed that the MIWs increased the shear capacity and the lateral stiffness with an average of 44.3% and 118.6%, respectively. Also, both the frames buildings with MIWs and the bare SWs buildings showed approximately equal lateral load capacities. Local damages in the RC vertical elements and yielding of the MIWs were recorded simultaneously. However, the MIWs yielding (and also failure) occurred earlier for the frames buildings compared with the SWs buildings in which the stress was relaxed in their MIWs.