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.

Flexural Behaviour Of ECC Coupling Slab In Coupled Shear Wall Structure

Flexural stiffness or effective width of floor slab acting as coupling beam is very important for the analysis of Coupled Shear Wall (CSW) systems. New generation of high performance concretes provide an alternative to conventional concrete to enhance the performance of coupling slabs. This research investigates the flexural behaviour of coupling slabs incorporating Engineered Cementitious Composite (ECC) compared to conventional Self-Consolidating Concrete (SCC). The high strain capacity and low crack width makes ECC an ideal material for coupling slab. Non-linear coupling action of ECC slabs is investigated experimentally with small-scale models having variable geometric parameters under monotonic loading. The performance is judged based on moment-rotation response, flexural stiffness/effective width, deflection, cracking, strain development and failure modes. Design charts for flexural stiffness/effective width of coupling slabs are presented in pre-cracking/cracking/post-yielding stages. CSW systems with ECC are found stronger and ductile than their SCC counterparts confirming the viability of constructing such structures.

Flexural Behaviour Of ECC Coupling Slab In Coupled Shear Wall Structure

Flexural stiffness or effective width of floor slab acting as coupling beam is very important for the analysis of Coupled Shear Wall (CSW) systems. New generation of high performance concretes provide an alternative to conventional concrete to enhance the performance of coupling slabs. This research investigates the flexural behaviour of coupling slabs incorporating Engineered Cementitious Composite (ECC) compared to conventional Self-Consolidating Concrete (SCC). The high strain capacity and low crack width makes ECC an ideal material for coupling slab. Non-linear coupling action of ECC slabs is investigated experimentally with small-scale models having variable geometric parameters under monotonic loading. The performance is judged based on moment-rotation response, flexural stiffness/effective width, deflection, cracking, strain development and failure modes. Design charts for flexural stiffness/effective width of coupling slabs are presented in pre-cracking/cracking/post-yielding stages. CSW systems with ECC are found stronger and ductile than their SCC counterparts confirming the viability of constructing such structures.

EFFECT OF SHEAR WALL ON PERFORMANCE OF MULTISTOREY BUILDING

Seismic force, predominantly being an inertia force depends on the mass of the structure. As the mass of the structure increases the seismic forces also increase causing the requirement of even heavier sections to counter that heavy forces. And these heavy sections further increase the mass of the structure leading to even heavier seismic forces. Structural designers are met with huge challenge to balance these contradictory physical phenomena to make the structure safe. The structure no more can afford to be rigid. This introduces the concept of ductility. The structures are made ductile, allowing it yield in order to dissipate the seismic forces. A framed structure can be easily made ductile by properly detailing of the reinforcement. But again, as the building height goes beyond a certain limit, these framed structure sections (columns) gets larger and larger to the extent that they are no more practically feasible in a structure. There comes the role of shear walls. Shear walls provide ample amount of stiffness to the building frame resisting loads through in plane bending. But they inherently make the structure stiffer. So, there must be a balance between the amount of shear walls and frame elements present in a structure for safe and economic design of high-rise structures. Here an attempt has been made to study the behavior of different structures of reinforced concrete with different heights with and without shear walls. Coupled shear walls have also been studied to understand the comparative merit or demerit of framed structures with shear wall structures. Studies have been carried out on sample model structures and analysis has been carried out by ETABS software. It has been ensured to consider sample models that represent the current practices in structural design to include different structural configurations. Models having varied structural configurations like framed, shear wall, coupled shear wall, central core shear wall, core in core etc. have been taken into consideration. The inherent asymmetry present in the structures have also been dealt. The results have been tabulated and plotted to study their comparative behavior and interaction with each other. The findings of the study have been summarized and discussed.

Invistigating the effects of frp bars on the seismic behavior of reinforced concrete coupling beams

Sometimes, it is necessary to install regular openings like windows or doors in the shear walls. Such openings require special reinforcement. There are several methods for reinforcing deep beams, one of which is the use of fiber reinforced polymer bars. In this study, an experimental work on a coupled shear wall has been used to mode the system by using finite element method with ABAQUS software. The finite element model was established based on part of the experimental study and verified with the other parts of the experimental results. The comparison shows good agreement. In the study, three different types of fiber reinforced polymer bars were considered in improving the mechanical and structural behavior of RC coupling beams. Results of the finite element analysis showed the superiority of the CFRP bars in improving seismic behavior of the coupled shear wall comparing to GFRP and BFRP.