Behavior Of Reinforced Concrete Infilled Frames Under Dynamic Loading: Part 1

Many buildings used by the U.S. Army are classified as reinforced concrete frames with masonry infill walls. There is therefore a need to develop reliable analysis tools to predict the real strength and the dynamic response of such infilled frames. For that reason, a comprehensive multi-year study was carried out by the staff of the U.S. Army Construction Engineering Research Laboratories (USACERL). In that study, several half-scale specimens consisting of reinforced concrete frames (bare and with masonry infill), were subjected to simulated earthquake motions using a shaking table. Both in-plane and out-of-plane motions were applied to virgin specimens, previously damaged specimens, and repaired specimens. In the study reported here (carried out at the University of Texas at Austin) no additional experimental work was performed. In this study, the experimental data obtained by the USACERL was used to evaluate both the in-plane and out-of-plane behavior of infilled frames. Load-displacement characteristics were obtained; and maximum loads, deflections and internal strains were measured and assessed. Dynamic response was predicted analytically, using various mathematical idealizations. Finally, simplified analytical idealizations were developed to predict the strength and stiffness of infilled frames.