Experimental and Numerical Study on Seismic Behavior of An Infilled Masonry Wall Compared to An Arched Masonry Wall

Sassanid era arches are among the oldest arches in Persian architecture. In this study, an infilled masonry wall and a similar Sassanid era arched masonry wall, both with clay bricks (square bricks of 195 mm long) and clay and gypsum mortar, are compared and their seismic behaviors are tested under cyclic loading (as per protocol). The dimensions of both the walls are of L 1720 mm, W 1500 mm and H 195 mm. The diameter of the vault is 900 mm. For loading, first, pre-pressure of 58 kN is applied on the specimens; then, upon this constant pre-pressure, the lateral cyclic loading is applied on the specimens. The results indicate that the arched wall can well withstand seismic forces. The maximum lateral force of 26.4 kN resulted in a 18.12 mm lateral displacement tolerated by the arched wall, while the infilled wall tolerated a maximum force of 56.53 kN at displacement of 9.12 mm. In the hysteresis curve of the arched specimen the pinching effect is observed, while in the hysteresis curve of the infilled specimen this effect is not visible. The infilled specimen in relation to the arched specimen has more energy dissipation. In specimen with arched opening, three plastic hinges occur. The first plastic hinge occurs at the arch crown and two hinges appear on the bottom of the side piers. The fracture mechanism in the arched wall is of crushing at the pressure toes of the wall and the same in the infilled wall is of crushing at the same points in addition to emergence of diagonal cracks in the wall and their expansion under increased load range. In order to validate the experimental results, the walls are modeled in ABAQUS software and concrete is used as masonry material in simulation. Concrete damaged plasticity model and macro modeling approach are adopted in this simulation. The hysteresis curves found for numerical modeling in both specimens are in good agreement with laboratory findings.