Behavior of Reinforced Concrete Infilled Frames Under Dynamic Loading: Part 2

A recent survey of U. S. Army buildings showed that a considerable percentage of them can be classified as reinforced concrete frames with infill masonry walls. In order to evaluate the strength and seismic behavior of such structures, the U. S. Army Construction Engineering Laboratory (USACERL) carried out an experimental program on several half-scale infilled frame specimens subjected to dynamic loading. Using a shaking table, both in-plane and out-of-plane simulated earthquake motions were applied to virgin, previously damaged, and repaired specimens. The experimental data obtained from this test series were then analyzed at the University of Texas at Austin. The objective of this work was to develop reliable analysis tools to predict the real strength and the dynamic response of infilled frames. Evaluation of in-plane and out-of-plane behavior of the infilled frames was performed using their load-displacement response. Maximum base shears, deflections, and internal strains were measured and assessed. Using various mathematical idealizations, the dynamic response of the specimens was predicted analytically. Finally, simplified analytical idealizations were developed to predict the strength and stiffness of infilled frames, and several design procedures were reviewed.