Dilated Brick Masonary Infills to Avoid the Diagonal Compression Struts During Lateral Reversed Cyclic Load

In high seismicity areas such as Indonesia, brick masonry has been widely applied as a partition as well as infills in reinforced concrete (RC) buildings. One of the disadvantages of using brick masonry infilled in RC buildings is that the diagonal compression struts may occur during the earthquake shaking, which may influence the seismic performance of its structure. Due to its diagonal strut, the columns will undergo additional axial and shear loads. The situation may collapse columns early. This study proposes the dilated brick masonry infill to overcome the above disadvantage. The advantage of its dilated brick masonry was obtained through structural testing of three 1:4 scaled-down RC frame specimens applied to lateral reversed cyclic loading. The specimens include one bare frame, one with full masonry infill, and one with dilated masonry infill. For the specimen with the dilatation masonry, there was a dilatation of about 20 mm between the masonry and columns. During structural testing, the deformations of specimens were measured. The cracks pattern of the columns and masonry was also drawn to observe the failure mechanism of the specimens. Comparing the experimental results shows that the dilated masonry infill has suitably avoided the diagonal strut on the masonry infill. As we predicted, the ductility of the frame with dilated masonry was similar to the bare frame without significantly reducing its seismic capacity. The observation during the test showed that the interface between masonry infills and the beams was weak. The applied static reversed lateral loading made the area experience shear stress—the cracks on the masonry started from its area. Strengthening of its interface areas is required to apply this proposed dilated masonry infill.