| A comprehensive study has been conducted to evaluate the safety of existing masonry infilled R/C structures under earthquake loadings. Fourteen 1/2-scale frame specimens have been tested to evaluate the influence of the relative strength and stiffness of an infill with respect to those of the bounding frame, the lateral load history, the panel aspect ratio, the magnitude and distribution of vertical loads, and the adjacent infilled bays on the performance of these structures. The experimental results show that the addition of infill panels results in a major improvement in the strength and energy-dissipation capability of these frames. The test results have been extrapolated to obtain the dynamic properties of the prototype structure and, thereby, to study its performance under seismic loadings. The results have demonstrated a remarkable improvement of structural performance due to the infill. Furthermore, simple analytical methods have been developed in this study to predict the lateral strength and stiffness of infilled frames. The predictive value of these methods has been validated by the experimental results. Finite element analyses have been conducted on the frame specimens. To this end, two interface models have been developed in this study. One simulates the behavior of the interface between the frame and masonry infill and that of the mortar joints, and the other is to model the bond-slip behavior of reinforcing bars in concrete. The resulting finite element models are able to capture both the failure mechanisms and lateral strengths of the infilled frame specimens. |
