Concerns Regarding the Seismic Design of Reinforced Concrete Haunched Beams

This paper discusses: 1) current practices in the design of reinforced concrete (RC) buildings with haunched beams, 2) the behavior observed in such structures when subjected to moderate or strong earthquakes, 3) research efforts made to understand the behavior of RC haunched beams, and 4) the need to incorporate recommendations in building codes that would insure the ductile detailing of these beams in both flexure and shear. The case study of a 12-stroy RC building is presented to show that current design practices do not favor an adequate lateral load capacity of the building and that undesirable failure mechanisms could develop. Based on this study and past research findings, practical recommendations for the ductile detailing of RC haunched beams are proposed for both flexure and shear.