Coupled Shear Wall System Research Articles

Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams

Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams

Seismic performance analysis and control method of composite coupled shear wall with steel plate-fiber reinforced concrete coupling beams

This paper based on the study of steel plate-fiber reinforced concrete coupling beam components, designs a basic model of composite coupled shear walls with steel plate-fiber reinforced concrete coupling beams. The seismic performance of this model was numerically simulated using the ABAQUS finite element software, analyzing the stress distribution of various parts and the development pattern of plastic hinges in the structure. It also examines how factors such as axial compression ratio, coupling beam cross-sectional dimensions, single-sided wall limb aspect ratio, and total floor height affect the seismic performance of this type of coupled shear wall, providing a reasonable range for axial compression ratios and coupling ratios for composite coupled shear walls with steel plate-fiber reinforced concrete coupling beams. Based on the obtained reasonable axial compression ratio and coupling ratio, and using the analytical solution of the continuum method, a method for controlling the seismic performance of coupled shear wall structures was proposed. Results show that the composite coupled shear walls with steel plate-fiber reinforced concrete coupling beams exhibit high load-bearing capacity and lateral stiffness under inverted triangular horizontal loads, with good displacement ductility and strong energy dissipation capability, making it an excellent seismic performance coupled shear wall system. As the axial compression ratio increases, the displacement corresponding to the yield point and peak point of the structure gradually decreases, and the displacement ductility coefficient shows a trend of first increasing and then decreasing; it is recommended that when designing steel plate-fiber reinforced concrete coupling beam-coupled shear walls, the axial compression ratio should not exceed 0.3. Numerical analysis of coupling ratio-related parameters indicates that in high-intensity seismic design areas, the range of coupling ratios should be between 45% and 60%.

Bidirectional seismic performance and design approach of RC infill wall with PVC tubes

In some regions, masonry infill walls are replaced by cast-in-situ reinforced concrete (RC) infill walls to effectively solve problems such as leakage, long construction periods, and high out-of-plane vulnerabilities. However, these high-stiffness RC infills impose excessively high constraints on the adjacent structural components, leading to disadvantageous seismic responses. Therefore, a flexible connection is required to isolate the infill walls and main structures. However, flexibly connected RC infill walls are not widely used in practical engineering because they are weakly supported by relevant standards and codes and have an insufficient calculation basis, especially for evaluating out-of-plane seismic properties. This study considers a type of RC infill wall with a common layout of polyvinyl chloride (PVC) tubes for coupled shear wall systems. The in-plane and out-of-plane seismic performances of the system are studied using quasi-static loading tests and finite element analysis, respectively. The system exhibits satisfactory seismic properties during the test because the PVC tubes provide effective flexible isolation. Out-of-plane pushover analysis and bidirectional loading are successively simulated with different parameters to study the out-of-plane reliability of the infill walls with and without openings. Finally, a seismic design approach for such infill walls, considering both in-plane and out-of-plane resistances, is proposed and validated using novel and concise design formulas. The accuracy of the design approach is verified using finite element calculations.

Cyclic response and parametric study of a self-centering coupled shear wall system with disc spring devices

The use of the disc spring device (DSD) to provide a superior self-centering ability and ductility for shear walls has been investigated in both numerical simulation and pseudo-static cyclic loading tests. In the current study, the DSD is adopted to improve the resilience of the coupled shear walls. A finite element model of a present coupled shear wall is developed and verified by the experiment. Based on the prototype model, a model of the self-centering coupled shear wall system is built by installing two DSDs in the bottom corners of the wall piers. A parametric study is performed to provide a holistic evaluation on the effect of the stiffness, friction, and installation layout of the DSD. Results prove the resilience promotion of the traditional coupled shear wall by installing DSDs. The sufficient initial stiffness of DSDs can provide high overturning moment capacity and the second stiffness of DSDs is key in mitigating the residual displacement for the self-centering coupled shear wall. The friction between disc springs can enhance energy dissipation ability of the system. More installed DSDs would be beneficial for the ductility of the coupled shear walls.

Experimental evaluation of post-tensioned hybrid coupled shear wall system with TADAS steel dampers at the beam-wall interface

Considering the optimal seismic resistance of coupled shear walls and the perks of self-centering systems, throughout this research, the hysteretic performance of post-tensioned concrete “Coupled Wall” (CW) subassemblies with “Steel Coupling Beam” (SCB) equipped with “Triangular Added Damping and Stiffness” (TADAS) steel dampers was experimentally evaluated. To dissipate the energy input from the earthquake, metallic yield dampers of the TADAS type were used at the connection zone between the beam and the wall in this structural system. Using a SCB rather than a concrete beam was suggested to reduce beam damage and maintain the system’s self-centering capabilities during lateral loading. High-strength steel strands were employed to generate post-tensioning along the beam’s longitudinal axis in the “Coupled Wall System” (CWS) to reduce structure residual deformation under seismic loading. In the first portion of this research, an experimental assessment of the load–displacement behavior of TADAS dampers exposed to cyclic loads was performed. Then, at floor level, three ⅔-scaled CW subassemblies were constructed using a post-tensioned SCB and subjected to lateral quasi-static cyclic loading of increasing amplitude. Various post-tensioning stresses were applied to one subassembly lacking energy dissipation devices and two subassemblies with TADAS dampers. The findings demonstrate that TADAS-equipped subassemblies can endure major non-linear deformations up to 8% drift without struggling either residual deformation or severe injury. Installing TADAS dampers at the beam-wall interface heightened the specimens’ capacity to withstand lateral loads by 71% to 90% and considerably increased their potential to dissipate energy.

DEVELOPMENT OF DAMPED BRACED TUBE SYSTEM AND APPLICATION TO ACTUAL PROJECT

A new vibration control system, Damped braced tube system, is developed for adopting on super high-rise buildings in central Tokyo. This system consists of tube frame using elastic braces and damped slit where a portion of braces are replaced by dampers. Damped slit acting as link beam of coupled shear wall system can dissipate seismic energy very efficiently and contribute to succeeding to meet higher seismic criteria. This paper describes system outline and efficiency through numerical analysis of actual high-rise project expected to be one of the tallest towers in central Tokyo.

Test, Analysis, and Seismic Design Approach of RC Infill Walls Isolated by PVC Tubes in Coupled Shear Wall Systems

Test, Analysis, and Seismic Design Approach of RC Infill Walls Isolated by PVC Tubes in Coupled Shear Wall Systems

Simplified Design of Coupled Shear Wall Systems for Typical Building Configuration

Simplified Design of Coupled Shear Wall Systems for Typical Building Configuration

Introduction of a new metallic-yielding pistonic damper for seismic control of structures

A new damper with pistonic performance is presented in this research for seismic control of structures. A set of rectangular metallic yielding plates has been considered as the energy dissipating part for this device. The damper is configured in such a way that can provide the loading conditions as pure-bending for this part during cyclic motions. This configuration makes the damper to have an optimized flexural yielding mechanism and consequently a high-level of force capacity and damping ratio. The dissipator part is placed into a steel surrounding rigid box which has only one sliding translational degree of freedom along its longitudinal axis. Accordingly, the device can perform as a tension/compression piston with sufficient stability in other directions. The proposed metallic-yielding pistonic (MYP) damper can be used in various types of structural systems such as moment-resisting or braced frames and even coupled shear wall systems with the capability of dual or multiple-installation in each frame bay. In this research the hysteresis behavior of this damper has been numerically investigated. Then as a parametric study, the effects of various MYP design parameters on the damper hysteretic behavior were studied. Finally, the control performance of this device was seismically investigated in a one-story moment-resisting frame considering possible beam flange out-of-square imperfections. According to observed results, the proposed damping system is high-performance in seismic structural protection at low-value story drifts. Besides, it was able to significantly reduce the structural responses and residual deformations as well as the out-of-plane frame motions.

Equivalence of plastic strength and hysteretic behavior of box and I-shaped shear links

In seismic resilient structural systems like eccentrically braced frame and coupled shear wall system, a small beam-like segment known as the shear link is used as a replaceable structural fuse. Shear links dissipate seismic energy primarily by shear deformation. This study focuses on the numerical investigation of the shear capacities of short box-shaped and I-shaped links and the feasibility of interchangeability between them. For replacing links in post-disaster periods, this interchangeability between links of different shapes would allow designers to choose from a wider range of options leading to higher flexibility. Existing equations for the prediction of shear capacities were studied to find appropriate equations to be used for achieving equivalent hysteretic behavior by links of I-shaped and box-shaped sections. When shear capacities are estimated with the existing equations of the AISC code, the hysteretic behavior of a box-link differs from that of an I-link despite having the same shear capacity. These equations do not take into account the contribution of flanges in the resistance of shear forces. Instead, the alternative equations which include the full link depth are found to be more appropriate using which the same cyclic behavior can be achieved by either a box-link or an I-link (with the same shear capacity) in terms of hysteretic response, overstrength, and energy dissipation. An I-shaped link can be replaced with a box-shaped link of the same capacity and vice versa, when capacity prediction is done with the suggested equations.

The Effect of a Rigid Connection between the Slab and the Coupled Beam on the Seismic Performance of the Coupling Wall System

The evolution of the construction building is one of the urgent matters in the current era, especially for high and medium-rise buildings. The widely used frame shear wall system has the main sign for the resistance of the lateral load (seismic and wind loads), so adding the coupled shear wall system to the construction building can give sufficient lateral stability, which can be achieved by increasing stiffness, strength, and ductility of the system. However, much research had been studied the coupling beams in the shear wall system theoretically and experimental; the effectiveness of the slab performance on the system has a short thesis executed experimental with limiting factors. In other words, only a few studies have shown the effects of slabs on the behavior of the coupled beam, and these studies did not mention the representation of the model. This study aims to investigate the effect of the rigidity connection between the slab and coupled beam and to create a finite element model in 3D to get a full understanding of the behavior of the system with different cases and hence to get recommendations for constructing stability system, the interaction between the slab elements and the shear wall system can effect on the behavior of the building. Deformation, shear, and moment in the coupled beam consider as the main measurements of structure response; the measured responses with different models of building 4, 8, 12 stories have been investigated in 3D models to obtain the behavior of the interaction of the slab with the coupled wall system. Two cases have been created; one is made without slab between coupled beam, and the other with existence the slab. The results prove that the rigidity between the coupled beam and the slab diaphragm is more effective for stability versus the seismic load. It shows the response reduction in the coupled beam and hence the overall response of the structure modeling, which can be returned to the effects of interaction rigidity between elements of the coupled beam and slab.

Precast Concrete Coupled Shear Wall System of Modular High-rises Without In Situ Cores

Modular construction has been widely employed to build low-to-medium-rise buildings but limited for high-rises partly due to the knowledge gap about the lateral force resistance of modular high-rises. Most modular high-rises adopt in situ cores which still require substantial onsite works to resist lateral loads. Previous research developed a module wall system for modular high-rises to replace in situ cores. This study aims to propose coupling beams concealed in corridor slabs for modular high-rises without in situ cores. A 40-story public housing building in Hong Kong (HK) was adopted for the case study. A finite element (FE) model of precast concrete coupled shear walls was formulated using the OpenSees software and validated by reported test results. For the case building in the scenarios with and without coupling beams, the seismic and wind performances were respectively compared according to the results of the nonlinear dynamic analysis using the FE model and those of the nonlinear static analysis using an ETABS model of the building. The study not only proves that precast concrete coupled shear wall system is technically feasible to resist the seismic and wind loads for modular high-rises in HK but also facilitates the application of precast concrete modules in high-rise buildings.

Optimal placement of coupling elements of RC shear walls using endurance time method

Shear wall is one of the common lateral bracing systems in reinforced concrete structures. A coupling beam can be used due to architectural limitations for connecting two or multiple separate walls. Coupling beams are the most vulnerable elements of coupled shear wall systems. Therefore, beams could be designed to act as replaceable fuses in the system. This paper investigates the application of viscoelastic coupling dampers (VCD) and replaceable steel coupling beams in a high-rise building in a high seismicity region. A parametric study has been performed to determine the most effective number and location of the dampers to acquire enhanced seismic performance of the structure. The endurance time analysis method has been utilized to compare the seismic performance of a conventional steel coupled wall building to alternative designs incorporating VCD. The results show that the structure with positioning the coupling beams of P2 in which 25% of coupling beams are VCD has had 21% less inter-story drift ratios compared to P1, where all coupling beams are replaceable steel coupling beams (RSCBs). VDCs allow the natural period of the structure to enhance. By replacing the RCSB with less stiff VCDs, the lateral stiffness of the structure is reduced and the natural period is shifted beyond the predominant periods of regular earthquakes. The added damping provided by using the VCDs dissipates seismic energy and efficiently controls excessive drifts.

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.

Seismic displacements and behaviour factors assessment of an innovative steel and concrete hybrid coupled shear wall system

The objective of this research is to facilitate the design process of innovative steel and concrete hybrid coupled wall system, which is obtained through the connection of a reinforced concrete (RC) wall to two steel side columns by means of steel links. To this end, a group of 120 innovative hybrid coupled wall systems subjected to a set of 100 far-field ground motions are selected. Thousands of nonlinear dynamic time histories on the basis of incremental dynamic analysis (IDA) are carried out in order to generate a databank of specified response quantities. Subsequently, nonlinear regression analyses are conducted in order to derive simple formulae which offer a direct estimation of: fundamental periods of vibration, seismic displacements, ductility demands and behaviour factors q for both designed and undesigned structures at different limit states; involving steel first yielding of internal wall, various predefined maximum inter-storey drifts and links rotations values. The effect of the following parameters: number of storeys, coupling ratio value, steel area ratio of boundary elements, uniformity status of shear links, and length of links is thoroughly investigated. The results indicate that storeys number and uniformity status parameters have the largest influence on the most of response quantities. The current q behaviour factor value is approximately suitable for low-rise building, but it is highly underestimated in medium-rise buildings. Furthermore, the equal-displacement rule clearly overestimates the roof ductility. Overall, this study bridges the gaps about the innovative hybrid coupled wall system design methodology and enables a rapid seismic assessment of such structures.

Estimation and development of innovative hybrid coupled shear wall system using nonlinear dynamic and fragility analysis

The Innovative hybrid coupled shear wall system (HCW) is one of the most advanced economical structural systems which has already been conducted. It constitutes of RC shear wall connected to two side steel columns by mean of replaceable coupling steel links. The main design objective of this system is to withstand lateral loads with minimized or even no damage of non-replaceable components (i.e. RC wall and steel columns), while the replaceable coupling steel links could undergo severe damage. This system still highly lacks investigations and detailed estimation as well as being of low efficiency in low-rise buildings. In this research, the emphasis is upon the estimation of the most efficient current HCW systems which have been recommended in literature so far, to be thoroughly calibrated against equivalent conventional RC wall system. Furthermore, new recommendations are presented in intention of optimizing the performance of HCW system to efficiently achieve the design objective through multi-type modifications: links arrangement, internal wall structure and combined systems. The study implements an advanced modelling procedure and extensive nonlinear dynamic analyses with fragility assessment to obtain a highly reliable evaluation. The newly proposed methods reveal excellent efficiency, especially in low-rise buildings.

Effect of deviation angle between principal stress and diagonal reinforcement direction on seismic performance of RC coupling beams

In a coupled shear wall system, the reinforced concrete (RC) coupling beams are allowed to form plastic deformations in order to dissipate seismic energy while maintaining the stability of overall structural system. However, the coupling beams are generally shear-dominated members because of their short shear span-depth ratio, which is usually less than 2. Therefore, under high seismic shear demand, the energy dissipation capacity and ductility of these members are sharply reduced compared to RC beams with larger shear span-depth ratio due to severe pinching effect. In order to avoid any undesirable structural behavior, the current standards stipulate the use of diagonal reinforcing bars in RC coupling beams with short span-depth ratio. Previous studies show that the diagonal reinforcement arrangements improve the structural performance of coupling beams, but the behavior of such members under cyclic bending and shear may significantly vary depending on the orientation of diagonal reinforcement. In this study, the effects of deviation angle between principal stress and diagonal reinforcement direction in the failure region, were experimentally investigated considering the potential failure modes of the coupling beams. Six RC coupling beams were tested under reversed cyclic bending and shear during this research. Experimental results show that the ductility ratio and the energy dissipation capacity of RC coupling beams vary, depending on the orientation of the diagonal reinforcement even when the same amount of diagonal reinforcement is provided. The structural performance of RC coupling beams improves as the deviation angle between direction of principal stress and the diagonal reinforcement becomes smaller. Finally, a finite element method (FEM) analysis was carried out for the test specimens. The FEM analysis results closely agreed with experimental observations that both the ductility ratio and energy dissipation capacity were larger for members with lowest deviation angle.

Experimental comparative study of coupled shear wall systems with steel and reinforced concrete link beams

SummaryThis paper aims to investigate the seismic performance improvement effect of coupled shear wall with steel link beams under cyclic lateral loading. The quasi‐static tests on two 1/3‐scaled specimens, including one coupled shear wall with steel link beams and one coupled shear wall with conventional concrete link beams, were conducted. These two specimens were designed with similar lateral initial stiffness and tested under the same gravity and lateral cyclic loading procedure. The specimen with concrete link beams exhibited sequence shear failures of link beams from top to bottom storey after completing 22 loading cycles. However, the specimen with steel link beams sustained ductile and plump hysteretic behavior under the same loading cycles. The lateral load‐resisting capacity of the specimen with steel link beams is 2.2 times of the specimen with concrete link beams. The experimental results demonstrated great advantages of steel link beams in improving seismic performance of conventional coupled shear wall systems.

Fragility functions of different groups of diagonally reinforced concrete coupling beams (DRCBs)

Diagonally reinforced concrete coupling beams (DRCBs) act as a fuse element that dissipates most of the seismic energies imparted to coupled shear wall systems during earthquakes. The objective of this study is to develop the fragility functions of different groups of DRCBs: (1) all DRCBs, (2) DRCBs conforming to the ACI 318-14 (Building code requirements for structural concrete and commentary (ACI 318-14), American Concrete Institute, Farmington Hills, 2014) confinement options A and B, and (c) DRCBs not conforming to the ACI 318-14 confinement options. Forty-three specimens were collected from nineteen previous experimental studies to estimate their empirical fragility using four different damage states. It was found that maximum shear stress (υmax) played an important role in the fragility curves. Without considering υmax, the fragility of DRCBs was significantly underestimated for DRCBs with υmax 4.0. In this study, fragility curves were constructed considering the level of υmax. Mean chord rotations (μθ) of DRCB specimens were estimated for life safety and collapse prevention limit states, and compared to corresponding limiting values specified in ASCE 41-17 (Seismic evaluation and retrofit of existing buildings, American Society of Civil Engineers, Reston, 2017. https://doi.org/10.1061/9780784414859). DRCBs conforming to the ACI 318-14 confinement options produced μθ larger than the limiting values whereas μθ of DRCBs not conforming to the ACI 318-14 did not exceed the limiting values.

Effect of transverse reinforcement on the seismic behavior of diagonally reinforced concrete coupling beams

Coupled shear wall systems have been more popularly used in high-rise building construction in urban areas due to their efficiency in sustaining lateral loads as well as economic effectiveness. During earthquakes, coupling beams in the coupled wall system act as a seismic fuse element that dissipate most of seismic input energy exerted in the system. Diagonally reinforced concrete coupling beams (DRCBs) have been developed for this purpose. The objective of this study was to acquire test data of DRCBs of with different amount of transverse reinforcement and to evaluate the seismic behavior of these DRCBs. Quasi-static cyclic tests were conducted using seven DRCB specimens with different amounts of transverse reinforcement and different aspect ratios. Four specimens had Ln/h of 2.0, whereas it was 3.5 for the other three specimens. The shear strengths of individual specimens were compared to that calculated from the shear strength equation specified in ACI 318-14, and their deformation capacities were compared to those specified in ASCE 41-17. It is observed that the amount of transverse reinforcement in DRCBs played an important role in their shear strength and deformation capacities, indicating that the contribution of transverse reinforcement needs to be incorporated to ACI 318 shear strength equation and ASCE 41-17 model parameters.