A new empirical model for shear strength of reinforced concrete beam–column connections

Abstract

A new empirical model to estimate the joint shear strength of both exterior and interior beam-column connections is proposed. In the model, four parameters that have the most influence on joint shear strength are considered.Among these four, a new parameter is introduced to consider the bond condition and the possibility of beam bars transferring joint shear force into the columns. Consideration of this parameter in the model significantly improves the accuracy of the predicted joint shear strength. To calibrate the model, a large database of 98 reinforced concrete (RC) exterior and 73 RC interior beam-column connections displaying joint failure mode was compiled from the literature. A parametric study was also carried out to evaluate the dependence of the predicted to tested joint shear strength ratio on the four influence parameters using the database. The proposed model showed superior performance over existing models. Moreover, comparisons of the predicted joint shear strength with experimental results and with four existing models showed the accuracy of the proposed model.

Sustainable RC Beam-Column Connections with Headed Bars: A Formula for Shear Strength Evaluation

“…From their study, the concrete compressive strength f c , in-plane geometry (interior, exterior, or knee connections), dimensions of the beams and columns (h b , b b , h c , b c ), joint transversal reinforcement, and beam reinforcement are among the influencing parameters for the shear strength of the conventional beam-column joint. Furthermore, the bonding condition which is strongly influenced by the development length and the details of the beam reinforcement bars, are also known as the influencing parameters for the shear strength of the conventional joint [4]. In the following part, the influencing parameters for the joint shear strength of connections with headed bars are evaluated by using the collected database.…”

“…This design strategy is called the "strong column-weak beam" philosophy. In practice, the prediction of the beam bending moment capacity is relatively relevant, while the prediction of the joint shear strength is still to be investigated [1][2][3][4][5]. This is why numerous studies have been performed to investigate the behavior of beam-column joints.…”

“…The relevancy of the formula However, the studies about the joint shear strength of the exterior beam-column connections, in general, and of the exterior beam-column connections with headed bars, in particular, are still incomplete. Recent studies showed that the shear strength of exterior RC beam-column joints is influenced by the concrete strength, the joint panel geometry, the confinement of reinforcement rebars, the column axial load, and the reinforcement details at the joint location [4,[12][13][14]. Lim et al [15] used numerical methods to analyze the influences of reinforcement details on the performance of beam-column connections under the blast loads; the authors showed that the amount of the diagonal reinforcement at the joint core was a crucial factor.…”

“…Lim et al [15] used numerical methods to analyze the influences of reinforcement details on the performance of beam-column connections under the blast loads; the authors showed that the amount of the diagonal reinforcement at the joint core was a crucial factor. The influencing factor of the joint shear strength of beam-column joints with beam reinforcement bars anchored by the conventional 90 • hooks have been analyzed by Tran et al [4], while similar investigations for the exterior beam-column joints with headed bars have not yet been analyzed. Kang and Mitra [16] used binomial logistic regression methodology to establish a statistical model which could assess the importance of different parameters on the performance of beam-column connections with headed bars, but the joint shear strength and the prediction of joint shear strength were not investigated.…”

Shear strength model of reinforced-concrete exterior joint under cyclic loading

“…However, many experimental studies have shown that failure of the joint not only occurred at the joint core, but also developed into the upper and lower columns Tran, 2014, 2015;Wang et al, 2012). In addition, a recent study (Tran et al, 2014) showed that the contacting area between the beam longitudinal reinforcement and the surrounding concrete has a significant role in the joint shear strength. These facts lead to the idea that the beam longitudinal reinforcement tensile force transferred just a fraction of that force into the joint core.…”