Shear Strength of Exterior Beam-column Joints Under Seismic Loading

Beam-column joints in reinforced concrete frames are critical regions, because of the high shear forces and bond breakdown that can be induced within them if their shear strength is not adequate. Although the first experimental study on beam-column joints was done in the first sixties, only in the last years the researches on joints have been intensified. The lessons learned after the earthquakes and the vast number of parameters affecting the joint behavior have stimulated a lot of researchers to experimentally investigate and analytically study the connection under simulated earthquake forces. Nevertheless, no specific design tool has nowadays been found, and hence a lot of design code recommendations and analytical expressions for computing the exterior beam-column joints shear strength under seismic loading exist, but are not able to supply an accurate prediction, mainly because of the several parameters involved. In this paper an approach for interpreting and modeling the behavior of beam-column joints subjected to earthquake loading at failure is proposed. This approach leads to a very simple and accurate shear strength expression.