Influence of a window-type opening on the shear response of partially-grouted masonry shear walls

摘要

This paper focuses on assessing the effects of the presence of a window-type opening on the shear behavior of partially-grouted reinforced masonry (PG-RM) shear walls. For this purpose, this work analyzes previously reported test results of three PG-RM walls tested under in-plane cyclic lateral loading. The main variable of the tested walls is the size of a central window. Therefore, all the walls had the same external dimensions (a height-to-length aspect ratio equal to 1.02). The performance of the walls is analyzed and discussed in terms of maximum shear strength, drift, degradation of stiffness, displacement ductility, dissipation of energy, and equivalent viscous damping. The damage evolution in the tested walls is investigated using digital image correlation (DIC) technique. Finally, the paper compares the accuracy of the Strut-and-Tie method and five existing shear equations to estimate the maximum lateral capacity of PG-RM walls with openings. In this comparative analysis, seven numerical cases of walls with openings previously validated are also considered.Based on the results, the study has confirmed that the presence of a central window in a PG-RM shear wall reduces the shear strength and ductility of the entire wall, and increases the rate of degradation of lateral stiffness. Although a significant disparity was not seen in the shear strength of the two tested walls with openings, they exhibited differences in the damage progression, the total amount of dissipated energy and the equivalent viscous damping during the tests. In addition, the experimental evidence indicates that although damage is concentrated on the piers of the walls, it also propagates to the segments below the openings. Therefore, there is uncertainty about how much the properties of wall segments near the openings affect the global behavior of the wall. The assessment of different methods to estimate the lateral resistance of a PG-RM shear wall with openings shows that the sum of individual contributions of the piers gives accurate predictions provided the expression used to estimate the resistance of piers is accurate enough.