Seismic behavior of hybrid coupled shear wall with replaceable U-shape steel coupling beam using terrestrial laser scanning

The hybrid coupled shear wall (HCW) with replaceable coupling beam (CB) is an optimal component to recover buildings promptly after a severe earthquake. However, the reinstallation may be difficult or impossible with an identical CB because of the inelastic relative dislocation between two wall piers. This study proposes a novel HCW with different reinforcement ratios in the connection, which was tested under cyclic loading. After the test, the bolt holes can be located through terrestrial scanning, which is then utilized to fabricate a new CB that can accommodate the deformation between two wall piers. The newly replaced HCW system was also tested. As a result, all virgin test specimens fail in web fracture and show a significant inelastic chord rotation of 0.2 rad, exhibiting an excellent energy dissipation capacity. Meanwhile, the new method to locate the bolt holes after the test is feasible. The replaced HCW fails in the pull-off of anchor bars and shows poor seismic behavior due to the unpatched concrete cover in the connection. To improve the energy dissipation for the replaced HCW, high-strength grouting in the connection can be used and high-strength material can be used to replace the usual anchor bolts.

On the Behavior of Coupled Shear Walls: Numerical Assessment of Reinforced Concrete Coupling Beam Parameters

Modern construction of high-rise and tall buildings depends on coupled shear walls system to resist the lateral loads induced by wind and earthquake hazards. The lateral behavior of this system depends on the structural behavior of its components including coupling beams and shear walls. Although many research studies in the literature investigated coupling beams and shear walls, these studies stopped short of investigating the coupled shear walls as a system. Therefore, in this research, the effect of the coupling beam parameters on the nonlinear behavior of the coupled shear walls system was investigated. The full behavior of a 10-story coupled shear wall system was modeled using a series of finite element analyses. The analysis comprised of testing several coupling beam parameters to capture the effect of each parameter on system response including load-deflection behavior, coupling ratio, crack pattern, and failure mechanism. The results indicated that a span-to-depth ratio equal to two is a turning point for the coupling beam behavior. Specifically, the behavior is dominated by ordinary flexure for a ratio of more than two and deep beam behavior for a ratio of less than two. This study showed that the coupling beam width does not have a significant effect on the coupled shear wall response. Additionally, it was concluded that the excessive coupling beam diagonal reinforcement could significantly affect the coupled shear walls behavior and therefore an upper limit for the diagonal reinforcement was provided. Moreover, limitations on the longitudinal and diagonal reinforcement and stirrups are presented herein. The analysis results presented in this paper can provide guidance for practitioners in terms of making decisions about the coupling ratio of the coupled shear walls.

Influence of coupling beams to the energy dissipation of coupled steel plate shear wall

Shear Plate Shear Wall (SPSW) is a lateral force resisting system that is usually used in high seismic regions. Opening can be accommodated by using coupled steel plate shear wall (CSPSW) where two or more SPSWs are placed adjacently and are connected by coupling beams. Maximum displacement, shear load capacity and energy dissipation are affected by the dimension of the coupling beams. The construction cost of the building can be reduced vastly by optimizing the size of the coupling beams where the capability of CSPSW to resist the earthquake is maximized. Thus, the objective of this study is to determine the behaviour of maximum displacement, shear load capacity and energy dissipation of the CSPSW when the width, depth and length of the coupling beams are varied. Fourteen CSPSW models were analysed by ABAQUS software, where the models were subjected to lateral cyclic loading as accordance to ATC24. Maximum displacement of the CSPSW was not affected by the dimensions of the coupling beams. Shear load capacity was increased as either the width or the depth of the coupling beam was increased, and achieved its maximum value when the length of the coupling beam was 1000 mm. The optimum width, depth and length of the coupling beam to maximize the energy dissipation of the CSPSW models were 200 mm, 1000 mm and 1000 mm, respectively.

SEISMIC MITIGATION EFFICIENCY STUDY OF THE COUPLING BEAM DAMPER IN THE SHEAR WALL STRUCTURE

Coupling beam damper can be easily repaired in the post-earthquake, which can dissipate the seismic energy of the structure in the earthquake action. In this paper, the seismic mitigation efficiency of the coupling beam damper in the shear wall structure is analysed by using the fast nonlinear analysis method. Meanwhile, the effect of the layout location and number of the coupling beam dampers on the seismic mitigation efficiency of the structure are studied. Finally, the effect of the performance parameter of the coupling beam damper on the seismic mitigation efficiency is also analysed. The results indicate that: the story shear force and the drift angle of the shear wall structure can be effectively decreased because of the coupling beam damper, and the maximum decreased amplification of the story drift angle and base shear force can reach up to 16.7% and 8.8% respectively. Relating to the decreased amplification of the base shear force, the decreased amplification of the story drift angle of the structure with coupling beam damper is obvious. The coupling beam damper installed in the upper part of the structure is more economical, because the deformation of the structural coupling beam is mainly concentrated in the upper part of the structure. To ensure economic of the structure with damper, the reasonable coupling damper performance parameter should be determinate according to the dynamic response of the shear wall structure in the earthquake action. The above research work can provide guidance for the seismic design of the shear wall structure.

Seismic Performance of LRS-FRP–Concrete–Steel Tubular Double Coupling Beam

To improve the ductility and seismic performance of a double coupling beam, the authors applied a polyethylene terephthalate (PET) sheet and steel tube to form fiber-reinforced polymer (FRP)–concrete–steel double-skin tubular (DST) composite coupling beams. A low-cyclic reversed experimental program was carried out which factored in the member form, steel tube diameter, and construction methods. The results indicate that the ductility and energy dissipation performance of double coupling beams—whether wrapped with a PET-FRP sheet or surrounded by an FRP–concrete–steel DST composite system—is a substantial improvement over the traditional reinforced-concrete double coupling beam (RC-DCB). The ductility coefficient and accumulated energy dissipation of the DST-DCB members improved above 170% and 2300%, respectively. These percentages compare to the RC-DCB and are based on the rupture of a PET-FRP sheet. The results are similar to those of the large rupture strain double coupling beam (LRS-DCB). Meanwhile, the external wrapped PET-FRP sheet does not affect the initial stiffness and peak strength of the RC-DCB. Relatively, the inner steel tube will improve the initial stiffness, yielding strength, and peak strength. DST-DCB members still have considerable deformability after 85% of peak strength since the external PET-FRP sheet provided an effective constraint effect on the core concrete and the inner steel tube could bear excellent shear deformation.