Analytical Model for Predicting Shear Strength of Unreinforced Exterior Beam-Column Joints

This paper presents an analytical model to predict the shear strength of reinforced concrete (RC) exterior beam-column joints with transverse reinforcement (denoted as unreinforced) in the joint region. Several existing analytical models developed for reinforced beam-column joints have shown limited success in assessing the shear strength of unreinforced joints due to an inapplicable shear-transfer mechanism. A new shear-strength model is proposed based on a mechanism consisting of two inclined struts in the joint. The proposed model is validated by the accurate prediction of the shear strength of many tests from published literature. The proposed model accounts for the variation of joint shear strength with the joint aspect ratio and the beam reinforcement ratio, using truss analogy and the deterioration of bond resistance, respectively. Finally, the joint moment-rotation relationship is estimated using the proposed model, and simulations are successfully pet formed for two published tests.