Shear Wall Specimens Research Articles

Seismic evaluation of flexure–shear dominated RC walls in moderate seismic regions

The current study focuses on the typical design practice for reinforced concrete shear walls prevailing in low to moderate seismic regions such as Thailand. A reversed cyclic quasi-static loading test is conducted to assess the seismic performance of a large-scale flexure–shear dominated reinforced concrete shear wall specimen with an aspect ratio of 2. A strong coupling effect of flexure and shear responses is observed, even though the shear strength is about 1·5 times the shear corresponding to the nominal moment capacity of the specimen. The final mode of failure is concrete crushing and the buckling of vertical reinforcement in the boundary zones. An analytical study is also conducted as a part of the verification of the experimental results. The analytical results of a commonly adopted fibre modelling approach for reinforced concrete shear walls are compared with a finite-element model based on modified compression field theory. Results of analytical study indicate that neglecting the coupling of flexure and shear responses can lead to unreliable predictions of the ductility and energy dissipation capacity of flexure–shear dominated reinforced concrete shear walls such as the one considered in this study.

Cyclic performance of precast concrete shear walls with a mortar–sleeve connection for longitudinal steel bars

To study the cyclic performance of precast concrete shear walls with a mortar–sleeve connection for longitudinal steel bars, a quasistatic test on shear wall specimens with flexure failure modes was carried out. The longitudinal steel bars in the precast concrete walls were connected with a steel sleeve using mortar. Test results indicated that the mortar–sleeve splicing effectively transferred the stresses on the vertical steel bars. The failure mode of the precast shear wall specimens had similar behaviors to that of the cast-in-place shear wall specimen, including the tensile yielding of the longitudinal steel bars and the crushing of the concrete in the compressive zone. The stiffness and energy dissipation capacity of the precast wall specimens were less than those of the cast-in-place wall specimen. The ultimate drift ratio of the precast wall specimens ranged from 1.69 to 2.08 %. The integrity of the precast shear walls with a vertical rough interface was better than that of the precast shear walls with a vertical step groove.

Experimental and numerical study of unstiffened steel plate shear wall structures

In order to investigate the seismic behaviors of unstiffened thin steel plate shear wall structure, tests of four three-story unstiffened steel plate shear wall specimens under cyclic loads were carried out. Parameters of the specimens included height-to-thickness ratio, span-to-height ratio and middle brace. The carrying capacity, hysteretic behavior, degraded characteristics, ductility, failure modes, energy dissipation capacity were analyzed and compared deeply. Besides, the nonlinear finite element method of shear wall structure was also established, which was verified by test results. Finally, the effect of column stiffness on load-carrying capacity was studied. The practical requirements of in-plane and out-of-plane stiffness of edge column were suggested. The experimental and numerical results showed that: this kind structure exhibits high strength, good energy dissipation capacity, and good ductility (the ductility coefficients are more than 3.0). When the inter-story drift angle reaches 1/50, the strength degradation is no more than 5%, indicating that the structure has good seismic behaviors. The span-to-height ratio has little effect on load-carrying capacity, while slightly affects the initial stiffness and ductility. The effect of height-to-thickness ratio (thickness) on load-carrying capacity is relatively larger than other factors. The middle braces do not improve the behaviors of structures. The stiffness of edge column has great effect on lateral load-carrying capacity of shear wall structures. The value of column stiffness index could be within 2.0–2.5 to achieve the sufficient constraints and economical benefit.

Experimental investigation of steel plate shear walls with in-span plastification along horizontal boundary elements

A cyclic pushover test of a three-story steel plate shear wall (SPSW) specimen was conducted to investigate the seismic behavior of this system when plastic hinge was predicted to develop along the span of horizontal boundary elements (HBEs). The experiment demonstrated that the in-span plastification caused a significant accumulation of plastic incremental deformations of HBEs. It also allowed to experimentally verify that moment–rotation hysteresis curves of HBE connections in SPSWs are not symmetric, but rather lopsided toward one direction, unlike that of special moment-resisting frames. Several of special moment connections experienced fractures, which is attributed to a higher rotation range prior to fracture of those connections. A finite element investigation of the tested specimen showed similar overall behavior to that observed during the experiment.

Experimental Study of Seismic Performance of Precast Fabricated Integration Shear Wall

A new method to infill the opening in the precast fabricated concrete shear wall was applied in China. In this paper, three geometrically identical precast fabricated shear wall specimens were constructed and tested under constant axial load and quasi-static cyclic lateral loading. The only difference among three specimens was the methods to infill the opening in the middle, the methods were respectively integration infill, masonry infill and without infill. The hysteretic curves, the skeleton curves, the failure process, the strain variation of reinforcement, the stiffness, the ductility and energy-dissipating capacity were obtained. The results and analysis showed that integration shear wall owns good seismic performance. Its bearing capacity, stiffness, energy-dissipating capacity are excellent while ductility is relatively poor. Masonry infilled wall and wall without infill also own good seismic performance.

Studies on Nonlinear Behavior of Shear Walls of Medium Aspect Ratio under Monotonic and Cyclic Loading

AbstractStructures designed according to performance-based seismic design (PBSD) are required to satisfy the target performance. PBSD requires extensive research for capacity evaluation and development of reliable nonlinear models. Shear walls are the ideal choice to resist lateral loads in multistoried RC buildings. They provide large strength and stiffness to buildings in the direction of their orientation (in-plan), which significantly reduces lateral sway of the building. Experimental studies on nonlinear behavior of shear walls of medium aspect ratios are limited. Nonlinear performance of medium aspect ratio shear wall specimens are studied on three identical shear wall specimens through application of monotonic and cyclic loading. In order to study the effect of axial load on the flexural behavior and ductility of shear wall, a parametric study is conducted using a layer-based approach, which is used to generate the analytical pushover curve for the shear wall and validated with the experimentally e...

Experimental study of reinforced concrete and hybrid coupled shear wall systems

Two approximately half-scale four-story coupled shear wall specimens were tested under both gravity and lateral displacement reversals. Specimen CW-RC, featuring traditional reinforced concrete (RC) shear walls and RC coupling beams, sustained ductile hysteretic response up to 3.00% drift. Specimen CW-S, featuring RC shear walls and steel coupling beam with low yield point steel (LYP) web, failed after completion of 2.00% drift cycles. The proposed connection detailing between the steel coupling beam and RC shear wall worked well in Specimen CW-S. Research results indicate that a ductile coupling beam design does not guarantee a ductile behavior of a coupled shear wall system. RC shear walls should be proportioned for axial and shear based on the provided coupling beam capacities. Design recommendations are provided.

Seismic capacity estimation of Steel Plate Concrete (SC) shear wall specimens by nonlinear static analyses

This study focuses on the structural behavior of the Steel Plate Concrete (SC) shear wall subjected to the lateral forces. An analytical approach to model the nonlinear behavior of the SC shear wall member efficiently is introduced in this paper. The pushover test results of the SC shear wall specimens in the previous study were first reviewed. Then, through the Finite Element (FE) modeling and structural analyses, the lateral load responses of the composite wall models were predicted to compare with experimental results. More specifically, nonlinear static analyses were performed to estimate the seismic capacity of the SC shear wall. The failure modes, strength and stiffness characteristics of the composite walls were obtained from the analyses. Good concurrences in the initial stiffness and displacement outcomes of the FE model and experimental results along with similar overall behavior were observed. It was also found that the analytical results depend a lot on the interface contact (i.e., boundary conditions between concrete and studs, steel reinforcement and welded studs, respectively) while modeling the SC shear wall using FE.

ANALYSIS OF HYSTERETIC RESPONSE OF GLASS INFILLED WOODEN FRAMES

The idea of the present study is to determine the performance of timber-glass hybrid shear wall exposed to monotone and cyclic horizontal in-plane load at the level of story height which is simulation of situation during earthquake or wind load. Fourteen quasi-static in-plane racking tests of shear wall specimens have been conducted where the specimens are composed of laminated timber frame and heat strengthened laminated glass panels, which are adhesive less, connected to wooden frame with friction only. For the evaluation of the experimental results the software (HYSPA+) was developed which is giving the information on normalised stiffness degradation and equivalent viscous damping coefficient based on the in-plane hysteresis response. The results are showing that described structural components are ductile with relatively high potential for dissipating of induced energy due to friction connection of glass panel and wooden frame. Observed damages were concentrated in timber frame joints, while glass panels remained entirely undamaged. In continuation of development of glass infilled wooden frames the configuration of frame joints will be modified to achieve its higher load bearing capacity and lower deformability.

Seismic Performance of Cantilever-Reinforced Concrete Masonry Shear Walls

This paper describes an experimental study of the seismic performance of cantilever-reinforced concrete masonry shear walls. As part of a research project on displacement-based design of masonry structures, 30 cantilever shear-wall specimens, made of fully grouted reinforced concrete masonry, were tested under reversed cyclic loading at the University of Texas at Austin and at Washington State University. Based on test results, the relationship between key design parameters and the nonlinear hysteretic response of the specimens was evaluated. The specimens exhibited predominantly flexural behavior, as intended, and their behavior was generally in good agreement with that reported in previous research work. Specimens constructed with masonry units containing recycled materials behaved similarly to otherwise identical specimens constructed with ordinary units, indicating the structural equivalence of those two types of units. Lap splices in the longitudinal reinforcement caused a reduction in wall performance. Walls with longitudinal reinforcement concentrated at jambs behaved similarly to walls with evenly distributed longitudinal reinforcement.

Seismic Behavior of RC Shear Walls Strengthened for In-Plane Bending Using Externally Bonded FRP Sheets

AbstractThis paper presents the experimental results of a study investigating the effectiveness of using externally bonded fiber-reinforced polymer (FRP) tow sheets for in-plane bending strengthening and repair of reinforced concrete (RC) shear walls. The repair/strengthening scheme is designed to enhance the flexural load-carrying capacity of the walls and prevent brittle shear-related failures. The experimental program consisted of the performance evaluation of the FRP system in seven RC shear wall specimens tested to failure under lateral loads. The effectiveness of two different anchoring systems to transfer the loads carried by the FRP sheets to the supporting elements of the wall was also investigated. The experimental results showed that the FRP system was successful in restoring (in repair applications) and increasing (in strengthening applications) the initial stiffness and ultimate load-carrying capacity of the walls, while maintaining a ductile response behavior and avoiding brittle shear failu...

Restoring Force Model Investigation of Short Pier Shear Wall

To study the seismic behavior of short pier shear wall, 6 short pier shear wall specimens are tested under low cyclic loading with axial load ratio of 0.2. Hysteretic rules and stiffness degradation rate are determined base on test results and feature points are defined by theory, restoring force model that considers the effect of two loading direction to hysteretic characteristics is proposed based on test research, which could be applied to the nonlinear dynamic analysis of the structure.

Analysis and seismic tests of composite shear walls with CFST columns and steel plate deep beams

A composite shear wall concept based on concrete filled steel tube (CFST) columns and steel plate (SP) deep beams is proposed and examined in this study. The new wall is composed of three different energy dissipation elements: CFST columns; SP deep beams; and reinforced concrete (RC) strips. The RC strips are intended to allow the core structural elements — the CFST columns and SP deep beams — to work as a single structure to consume energy. Six specimens of different configurations were tested under cyclic loading. The resulting data are analyzed herein. In addition, numerical simulations of the stress and damage processes for each specimen were carried out, and simulations were completed for a range of location and span-height ratio variations for the SP beams. The simulations show good agreement with the test results. The core structure exhibits a ductile yielding mechanism characteristic of strong column-weak beam structures, hysteretic curves are plump and the composite shear wall exhibits several seismic defense lines. The deformation of the shear wall specimens with encased CFST column and SP deep beam design appears to be closer to that of entire shear walls. Establishing optimal design parameters for the configuration of SP deep beams is pivotal to the best seismic behavior of the wall. The new composite shear wall is therefore suitable for use in the seismic design of building structures.

Experimental Study on Two-Side Constraint Steel Plate Shear Wall with Vertical Stiffeners

Two two-side constraint steel plate shear wall specimens with vertical stiffeners had been tested under low cyclic loading to study its seismic performance through the performance indexes of the Initial stiffness, hysteretic behavior, load-carrying capacity, destruction mechanism and so on. Test showed that as main lateral force resisting members two-side constraint steel plate shear wall with vertical stiffeners had a very superior seismic performance. So it is worth popularizing in the area of high seismic intensity.

Effect of Ground Motion Sequence on Response of Squat Reinforced Concrete Shear Walls

Most industrial and nuclear facilities rely on reinforced concrete structural walls as their primary seismic lateral-force-resisting components. In nuclear facility structures, squat walls commonly have an aspect ratio lower than 0.5 and are designed to be thick for radiation shielding and blast and fire protection. The combination of a squat and thick wall geometry causes very high wall stiffness and strength. However, there is significant uncertainty about expected strengths, deformation capacities, and failure modes of these walls in earthquake load sequences, such as main-shock/aftershock combinations. Hybrid simulation is an effective experimental method to examine these issues: it enables simulation of the seismic response of squat and thick shear walls without the need to recreate the often very large mass associated with the remainder of the prototype structure. A hybrid simulation program utilized two shear wall specimens to investigate the variations of squat wall responses caused by different earthquake magnitude sequences. The results of these simulations indicated that different earthquake magnitude sequences do not have a significant effect on the force-deformation response and failure mode sequence of squat reinforced concrete shear walls.

강섬유 및 폴리아미드 섬유로 보강된 철근콘크리트 벽체의 전단성능 평가

A concrete shear wall system is an ideal structural system that can effectively resist large horizontal cyclic loads such as earthquakes. In particular, a significant increase of the ductility in fiber reinforced concrete shear walls can prevent a brittle failure and thus can enhance seismic resisting capacity significantly. This study investigated the shear resisting capacity of shear wall specimens, which are constructed with steel fibers or polyamide fibers reinforced concrete, by comparing hysteresis curves obtained from reversal cyclic tests. The shear resisting force in the steel fiber reinforced concrete specimen was larger than those in plain and polyamide fiber reinforced concrete specimens, but the increase was not great. The shear resisting capacity of the polyamide fiber reinforced concrete specimen was larger than that of plain concrete specimen, but smaller than that of steel fiber reinforced concrete specimen.

Experimental Study on Damage Behavior of Reinforced Concrete Shear Walls Subjected to Cyclic Loads

Previous experimental research on shear walls has mainly focused on load carrying capacity, deformation, or hysteretic characteristics, with relatively little attention paid to individual damage states and their corresponding responses during the entire loading process until failure. The damage behavior of seven reinforced concrete shear wall specimens subjected to cyclic loading is presented in this study. The effects of the axial load ratio, transverse reinforcement ratio of confining boundary elements, and cross-section shape on damage characteristics, ductility, shear deformation, and crack width of the specimens were analyzed comprehensively.

Numerical Modeling of Slender Reinforced Concrete Shear Wall Shaking Table Tests Under High-Frequency Ground Motions

This article presents the numerical modeling of large-scale shake table tests of slender 8-story reinforced concrete (RC) shear wall specimens. Nonlinear time history analyses are carried out using reinforced concrete fiber elements (OpenSees, OS) and the finite element (FE) methods (VecTor2, VT2). The effects of the modeling assumptions are investigated, including: (a) the tension stiffening effect, (b) damping, (c) smeared vs. lumped reinforcement, and (d) the use of effective shear stiffness in OS. Good agreements are obtained between the numerical and experimental results. Using the proposed numerical modeling strategy, it is possible to investigate the nonlinear dynamic responses of slender RC wall structures with confidence.

Cumulative damage model of mid‐rise shear wall and its experimental verification

SUMMARYThe study concentrated on investigating the relationship of the continuous cumulative damage, macroscopic deformation development and failure process of mid‐rise shear walls. Nonlinear fiber element model considering the effect of cumulative damage is proposed for evaluating the seismic performance of shear wall. Numerical analyses of shear wall specimens are carried out according to the proposed model to obtain the evolution of damage index of the shear wall. Experiments of six L‐shaped shear wall specimens subjected to reversed cyclic loading are carried out to verify the proposed model. Correlation of damage index and performance level is established, which provides good reference for the safety assessment of the structure under seismic type of loading. The model is efficient to evaluate the seismic performance of shear wall proved by the satisfactory agreement between analytical and experimental results. Copyright © 2012 John Wiley & Sons, Ltd.

The Seismic Performance Test of Precast Prestressed Shear Wall

This paper describes the multilayer and high-rise structure of the precast prestressed shear wall, we made one shape T shape and linked limb shear wall specimens as the objects, we also made comparision with cast-in-place shear wall, the specimens were tested under high frequency and reciprocating horizontal load. And it is analyzed in yield load, bearing capacity, stiffness degradation, energy dissipation as well as ductility conditions by test data. The result shows that Wall’s damage concentrated in roots near the connection, where is the weak area of the precast prestressed concrete straight shear wall, and the wall show characteristic bending failure.