Code Approaches to Seismic Design of Masonry-Infilled Reinforced ConcreteFrames: A State-of-the-Art Review

Masonry infill (MI) walls are remarkable in increasing the initial stiffness of reinforced concrete (RC) frames, and being the stiffer component, attract most of the lateral seismic shear forces on buildings, thereby reducing the demand on the RC frame members. However, behavior of MI is difficult to predict because of significant variations in material properties and because of failure modes that are brittle in nature. As a result, MI walls have often been treated as nonstructural elements in buildings, and their effects are not included in the analysis and design procedure. However, experience shows that MI may have significant positive or negative effects on the global behavior of buildings and, therefore, should be addressed appropriately. Various national codes differ greatly in the manner effects of MI are to be considered in the design process from aseismic performance point of view. This paper reviews and compares analysis and design provisions related to MI-RC frames in seismic design codes of 16 countries and identifies important issues that should be addressed by a typical model code.