Lateral Behavior of Partially Infilled Reinforced Concrete Frames with Masonry Inserts

Abstract

Masonry infill walls increase the initial stiffness of reinforced concrete frames and attract more seismic shear forces on buildings thereby reducing the demand on the frame members. Sometimes window or ventilator openings have been left in the infill wall for architectural necessities. Many reinforced concrete constructions with such partial masonry infill face serious earthquake damages due to captive-column effect. In this study, an attempt was made to improve the performance of such structures by providing masonry inserts without completely closing the gap. Experimental investigations were conducted on partially infilled one-third scale reinforced concrete frames with and without masonry inserts under lateral loading. The partially filled masonry wall induced captive-column effect and leads to a severe failure of the column. On the other hand, the masonry inserts over the partial infill increased the stiffness of the structure by forming a compression strut thereby avoiding critical captive-column damage. Results demonstrated the failure with respect to strength, stiffness, ductility and hysteretic characteristics.

Keywords: Reinforced concrete frame, partial infill, captive-column effect, lateral loading