Engineering Structures 24 (2002) 1105–1117 www.elsevier.com/locate/engstruct A new design equation for predicting the joint shear strength of monotonically loaded exterior beam-column joints P.G. Bakir ab,* , H.M. Bodurog ˘lu a a Istanbul Technical University, Civil Engineering Department, Maslak 80626, Istanbul, Turkey b Postal address: Yazmaci Tahir sok, Derya apt. no 11/4, Catalcesme, Suadiye, Istanbul, Turkey Received 11 June 2001; received in revised form 8 March 2002; accepted 8 March 2002 Abstract In this study a new design equation for predicting the shear strength of monotonically loaded exterior beam column joints is proposed. For this purpose, the inﬂuence of several key variables on the behaviour of beam-column joints are inspected using results of parametric studies on an experimental database compiled from a large number of exterior joint tests. The design equation suggested has three differences from the previously proposed equations. First, the equation proposed considers the inﬂuence of beam longitudinal reinforcement ratio, which was not taken into account in previously suggested design equations. Second, as the inﬂuence of this parameter is taken into account, a more realistic estimate of the inﬂuence of joint aspect ratio is obtained. Third, the inﬂuence of stirrups is considered differently for joints with low, medium and high amount of stirrup ratios, in a way, which was not considered in previously suggested equations. The results showed that the proposed design equation predicts the joint shear strength of exterior beam column connections accurately with minimal standard deviation and is more reliable than the previously suggested equations.  2002 Elsevier Science Ltd. All rights reserved. Keywords: Reinforced concrete; Shear strength; Monotonically loaded exterior beam-column connections 1. Introduction It is now generally believed that beam-column joints can be critical regions in reinforced concrete frames under severe seismic effects. Beam-column joint failures have been observed in the 1980 El Asnam [1], 1985 Mexico [2], 1986 San Salvador [3], 1989 Lome Prieta [4] and 1999 Kocaeli earthquakes [5]. During the past forty years, signiﬁcant amount of research has been car- ried out on seismic behaviour of beam-column joints all over the world. However, compared to cyclically loaded joints, little information exists in literature for predicting the shear strength of monotonically loaded exterior joints. Remarkable differences exist in the design of joints for seismic loading or monotonic loading. Parameters such as column axial load, concrete cylinder strength, stirrup ratio, stirrup index, joint aspect ratio, beam * Corresponding author. Fax: +90-216-386-9742. E-mail address: gundes@itu.edu.tr (P.G. Bakir). 0141-0296/02/$ - see front matter  2002 Elsevier Science Ltd. All rights reserved. PII:S0141-0296(02)00038-X reinforcement detailing, the ratio of beam longitudinal reinforcement etc inﬂuence the joint shear strength dif- ferently for interior or exterior and monotonically loaded or cyclically loaded joints. This investigation was planned with the objective of adding useful data to the understanding of the inﬂuences of the above-mentioned parameters on the joint shear strength of monotonically loaded exterior beam-column joints. Surprisingly, none of the previously suggested design equations for mono- tonically loaded exterior joints consider the factors that inﬂuence joint shear strength such as beam longitudinal reinforcement ratio, joint aspect ratio and concrete cylin- der strength together. 2. Previously suggested design equations for exterior beam column joints In this section, the existing empirical design equations for predicting the shear strength of the monotonically loaded exterior beam-column joints are reviewed.