Reinforced concrete frames with mas

Reinforced concrete frames with masonry infills are still used as structural system to provide earthquake resistance in seismic regions where masonry is a convenient material due to economical and traditional reasons. Even though infilled frames can exhibit an adequate response when properly designed, severe damage and loss of life have occurred in past earthquakes. Some of the problems associated with the damage or collapse of infilled frame buildings are: irregular distribution of the masonry infills, inappropriate detailing of the reinforced concrete frame, partial infill, and deficiencies in materials and workmanship. However, inadequate design criteria and the lack of comprehension of the structural behaviour are also critical issues. It is very important, therefore, to develop simple and rational design procedures in order to obtain a safe and economical solution.Using the principles of capacity design, a new design approach is proposed for cantilever infilled frames, in which the ductile behaviour is achieved by controlled yielding of the longitudinal reinforcement at the base of the columns. A pre-cracked connection is induced between the infilled frame and the foundation, where plain round dowels can be placed to control shear sliding. The proposed procedure also assures a simple evaluation of the lateral resistance, avoiding the uncertainties associated with the complexity of the panel-frame interaction. The use of tapered beam-column joints with diagonal reinforcement is recommended in order to reduce the opening of the joints and to improve the transfer of the lateral forces from the frame to the masonry panel.