L.Z. Li

Experimental Study of Moderately Reinforced Concrete Beams Strengthened with Bolted-Side Steel Plates

Existing reinforced concrete (RC) beams can be effectively strengthened by attaching steel plates to the side faces of the beams using anchor bolts. The performance of this type of beam, bolted side-plated (BSP) beams, is mainly controlled by the degree of partial interaction at the steel-concrete interface. In this study, a total of seven moderately reinforced BSP beams with different steel plate depths and various bolt spacings were tested. Their behaviours were compared to the available test results for lightly reinforced BSP beams obtained by other researchers. The results show that moderately reinforced RC beams are more effective in increasing the flexural strength and ductility capacity using deeper steel plates than the use of a greater number of anchor bolts. It was also found that the longitudinal and transverse slips were controlled by both the stiffness ratios of the steel plates to the RC beam and the force-slip response of the anchor bolts.

Longitudinal Partial Interaction in Bolted Side-Plated Reinforced Concrete Beams

Reinforced concrete (RC) beams strengthened with bolted steel plates on their side faces are known as bolted side-plated (BSP) beams. The performance of BSP beams is closely related to the longitudinal partial interaction caused by the longitudinal slip on the plate-RC interface. In this study, an analytical model for the longitudinal slip and partial interaction was developed, and formulas for the BSP beams under several simple loading conditions were developed. The superposition principle was also proven applicable to the analysis of longitudinal slip, thus can be used to analyse the BSP beams under complicated loading conditions. The results of a previous numerical study were extracted to validate the analytical model, and an example was then presented to illustrate the applicability of the theoretical approach. This study enhances the understanding of the behaviour of BSP beams, and provides an approach to consider the influence of longitudinal partial interaction in the BSP strengthening design.

Shear Performance of Fire-Damaged Reinforced Concrete Beams Repaired by a Bolted Side-Plating Technique

AbstractThe aim of this paper is to study the shear performance of fire-damaged reinforced concrete (RC) beams repaired by the bolted side-plating (BSP) technique. A total of six RC beams were fabr...

Numerical Study on the Local Buckling Behaviour of Bolted Steel Plates in Steel Jacketing

A numerical simulation was conducted to investigate the local buckling behaviour of the bolted steel plates in steel jacketing technique. The numerical model was firstly validated by the results of a previous experimental study. Then a parametric study was conducted to investigate the influence of different restraint measures on the local buckling behaviour and the sensitivity of the buckling behaviour to the initial imperfection. Fitted formulae were developed to calculate the structural field capacity of the bolted steel plates, and recommended values of stiffener size were also provided to facilitate the strengthening design of steel jacketing.

Study of Moderately Reinforced Concrete Beams Strengthened by Bolted-Side Steel Plates

The strengthening technique which attaches steel plates to the side faces of existing reinforced concrete (RC) beams using anchor bolts has received worldwide acceptance in the past several decades. The performance of this type of beam, i.e. the bolted side-plated (BSP) beam, is mainly controlled by the degree of partial interaction at the steel-concrete interface. This partial interaction is a result of the longitudinal and transverse slips. This paper introduces an experimental study on the behavior of slips and shear force transfer in the BSP beams. A total of seven moderately reinforced BSP beams with different steel plate depths and bolt spacing were tested under four-point bending. Their behaviors were compared to the available test results for lightly reinforced BSP beams obtained by other researchers. Then a nonlinear finite element model was also developed to predict the behavior of BSP beams. The numerical simulation was also verified by the results of the experimental study successfully. The results show that moderately reinforced RC beams can be effectively enhanced in flexural strength and ductility by using deep steel plates. It was also found that the longitudinal and transverse slips were controlled by both the stiffness ratios of the steel plates to the RC beam and the force-slip response of the anchor bolts. This study enhances the basic understanding of behavior of BSP beams and the internal shear-transfer mechanism between the steel plates and the RC beam.