TY - JOUR
T1 - Shear transfer mechanisms in monotonically loaded exterior beam-column joints
AU - Bakir, P. G.
PY - 2006/10
Y1 - 2006/10
N2 - In this study, a new design equation is proposed for predicting the shear strength of exterior beam-column joints. For this purpose, the influence of several key parameters are investigated using an experimental database consisting of a large number of exterior beam-column joint tests. The equation proposed has three important differences from the previously suggested design equations. First, the equation considers the contribution of stirrups to the joint shear strength. Second, the equation takes the influence of the bond conditions of the beam bars into account, which was not considered in previously suggested design equations. Third, the equation takes the influence of the beam longitudinal reinforcement ratio into account. In order to investigate the reliability of the proposed equation, the basic mechanics of beam-column joints are investigated. For this purpose, a membrane element is considered which is subject to in-plane normal stresses in addition to in-plane shear stresses and the equations for the average normal stresses are derived from stress equilibrium, whereas, the average shear stresses are calculated from Mohr circle. The non-linear relationship between the stress and strain and the softening of concrete in compression caused by cracking due to tension (the influence of the principal tensile strains) in the perpendicular direction are also taken into account. The equation for the principal tensile strain is derived from Mohr circle and a complete picture of the shear resisting mechanisms within the joint is obtained. It is apparent that the proposed design equation is in agreement with the predictions of the joint mechanics. The equation proposed is also compared with the existing design equations as well as Code Recommendations. The results show that the proposed equation is an improvement on the existing design recommendations as it predicts the joint shear strength more accurately and with minimal standard deviation.
AB - In this study, a new design equation is proposed for predicting the shear strength of exterior beam-column joints. For this purpose, the influence of several key parameters are investigated using an experimental database consisting of a large number of exterior beam-column joint tests. The equation proposed has three important differences from the previously suggested design equations. First, the equation considers the contribution of stirrups to the joint shear strength. Second, the equation takes the influence of the bond conditions of the beam bars into account, which was not considered in previously suggested design equations. Third, the equation takes the influence of the beam longitudinal reinforcement ratio into account. In order to investigate the reliability of the proposed equation, the basic mechanics of beam-column joints are investigated. For this purpose, a membrane element is considered which is subject to in-plane normal stresses in addition to in-plane shear stresses and the equations for the average normal stresses are derived from stress equilibrium, whereas, the average shear stresses are calculated from Mohr circle. The non-linear relationship between the stress and strain and the softening of concrete in compression caused by cracking due to tension (the influence of the principal tensile strains) in the perpendicular direction are also taken into account. The equation for the principal tensile strain is derived from Mohr circle and a complete picture of the shear resisting mechanisms within the joint is obtained. It is apparent that the proposed design equation is in agreement with the predictions of the joint mechanics. The equation proposed is also compared with the existing design equations as well as Code Recommendations. The results show that the proposed equation is an improvement on the existing design recommendations as it predicts the joint shear strength more accurately and with minimal standard deviation.
UR - http://www.scopus.com/inward/record.url?scp=33749830664&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:33749830664
SN - 1070-9789
VL - 38
SP - 10
EP - 24
JO - Journal of Advanced Materials
JF - Journal of Advanced Materials
IS - 4
ER -