Masonry infills with window openings and influence on reinforced concrete frame constructions

Abstract

The influence of masonry infills with window openings on the seismic performance of reinforced concrete (RC) frames designed according to current code provisions is investigated. Seven third-scale, single-storey, single-bay frame specimens were tested under reversed cyclic, quasi-static, horizontal loading up to a drift level of 40‰. The parameters investigated include the opening location and the infill compressive strength. The assessment of the behaviour of the frames is attempted based on the observed failure modes, strength, stiffness, ductility, energy dissipation capacity, and degradation due to cycling. The experimental results indicate that the location of the window opening must be as near to the edge of the infill as possible in order to provide an improvement in the performance of the infilled frame. Specimens with strong infills exhibited better performance than those with weak infills. For the prediction of the lateral resistance of the studied single-bay, single-storey infilled frames with window openings, a special plastic analysis method has been employed with reference to typical damage modes. Furthermore, a continuous force-deformation model based on an equivalent strut approach is proposed for masonry infill panels containing window openings. The actual properties of the infill are based on the assessment of its lateral resistance by the subtraction of the response of the bare frame from the response of the infilled frame. © 2009 WIT Press.