Performance Of Shear Walls Research Articles

Experimental study on seismic performance of low strength shear walls strengthened with modified reactive powder concrete

Improper operation during construction and damages in long-term use environments will result in the shear walls being unable to meet seismic design and safety requirements. In order to further explore the impact of modified reactive powder concrete (MRPC) surface strengthening on the bending performance of shear walls, four shear walls were subjected to low cyclic loading tests. The effects of single-sided strengthening, double-sided strengthening, and different strengthening thicknesses on their seismic performance such as failure mode, deformation capacity, energy dissipation capacity, and stiffness degradation have been studied. The results show that the failure modes of four shear wall specimens were bending failure. Horizontal and oblique cracks appeared at the bottom and middle of the specimen, respectively, and the concrete at the corner was crushed and peeled off. For the specimen strengthened by MRPC, the strengthening layer was slightly warped, and the number of cracks is significantly reduced, which can effectively avoid the brittle failure of the specimen. The strengthening layer formed a good restraint on the internal concrete. MRPC can effectively improve the seismic performance of low bending strength concrete shear walls, and the ductility was far exceeded the expectations of the experiment. Double-sided strengthening was better than single-sided strengthening. Increasing the strengthening thickness can improve the flexural cracking capacity, but due to the interface between the shear wall and MRPC, it had little effect on the yield, peak and ultimate capacity. In addition, excessive thickness will reduce the ductility and energy dissipation capacity of the specimen.

Seismic behavior of shear walls partially strengthened with UHPC in boundary element

Inspired by studies on shear walls reinforced with high performance cement-based materials, this paper explores the applicability of ultra-high performance concrete (UHPC) for improving the seismic behavior of shear walls. In this study, a novel shear wall partially strengthened with UHPC in the boundary element was developed, in which the UHPC was cast into the potential plastic hinge region of the boundary element. Partial application of UHPC can reduce construction costs and promote its use in building structures. To study the influence of distribution height and width of UHPC and axial load ratio on the seismic performance, six shear walls with a shear span ratio of 2.1 were tested under axial load and cyclic lateral load. The failure modes, lateral load-lateral displacement hysteretic behavior and ductility of the shear walls were also investigated. The experimental results indicated that the partial application of UHPC in boundary elements could effectively improve the performance of shear walls. Moreover, even if the volume ratio of UHPC was only 0.12, the shear wall partially strengthened with UHPC still showed good seismic performance under a high axial load ratio, indicating that this type of shear wall can be applied to the high seismic intensity and high axial load ratio regions.

Experimental investigation of the hysteretic behaviour of single-story single- and coupled-panel CLT shear walls with nailed connections

The impact of wall-to-floor hold-downs, vertical spline joints, shear connectors, panel aspect ratio, and gravity loading on the performance of single storey cross-laminated timber (CLT) shear walls was experimentally investigated. The shear walls consisted of 191 mm thick 7-ply CLT panels with nail connected hold-downs, shear brackets, and plywood surface splines. First, the strength and stiffness of the hold-downs, vertical spline joints, and shear brackets were determined. Then, a total of 27 single and coupled shear walls with panel aspect ratios of 2.5 and 3.5, gravity loading of 20 kN/m and 30 kN/m, different hold-down strength as well as different nail spacing in the splines were tested under monotonic and reversed cyclic loading. The connector tests showed that the presence of washers, even with reduced nailing, significantly increased overall connection stiffness, capacity, and ductility. The shear wall tests demonstrated that the wall aspect ratio had the most significant influence on the shear wall performance. Increasing the number of shear brackets also resulted in higher capacity, deformation, and energy dissipation, while tighter nail spacing in the spline joints resulted significant higher capacity and stiffness in coupled shear walls.

Shear Performance of Large-Thickness Precast Shear Walls with Cast-in-Place Belts and Grouting Sleeves

Building industrialization has great significance for improving the efficiency of construction production, achieving the goal of energy saving and emission reduction, and promoting sustainable development. On the other hand, numerous thick wall structures with bulky dimensions and complex connection constructions have been applied into special engineering such as islands, tunnels, and deep sea projects. The precast structure is an open and complex system with a certain level of systematic risk for the whole life cycle. Moreover, structural mechanics and reliability, construction uncertainty, and resilience of precast thick wall structures still need to be revealed. For promoting the application of building industrialization to thick wall structures, nonlinear finite-element analyses on two types of large-thickness precast shear walls have been carried out based on original structural design specifications. The reinforcement connection configurations and the shear performance in terms of the load–displacement curve, lateral stiffness, ductility, energy dissipation capacity of shear walls with cast-in-place (CIP) belts, or grouting sleeves have been analyzed in detail. Numerical results show that the shear performance of two large-thickness precast shear walls is comparable to that of CIP walls. The relative error of the peak load is less than 10% for three specimens in flexural failure mode. The yield load of shear walls is relatively large and the stage between yield and failure is satisfactory. The shear performance of shear walls decreases slowly after reaching its peak value. Meanwhile, we have conducted the qualitative analysis of structural reliability for large-thickness precast shear walls in component production, quality inspection, wet work, and shear performance.

RESEARCH ON STRUCTURAL PERFORMANCE OF SHEAR WALL OF CLT CONSTRUCTION METHOD WITH STEEL BEAMS AND TENSION MEMBERS

This research proposes a structural system for CLT shear wall that demonstrates high CLT shear performance, high deformation capability, and a method for determining its target performance. CLT shear wall with steel beams, using tensile members prevent the brittle failure occurring at the tensile joint, is proposed. To verify the validity of the proposed method, experiments for full scale CLT shear wall specimens are conducted. Test results are simulated by analysis models. By using material property values that are close to the actual conditions in the experiment, the analysis model is able to accurately reproduce the experiment results.

Digital Twin for Monitoring In-Service Performance of Post-Tensioned Self-Centering Cross-Laminated Timber Shear Walls

A digital twin (DT) can be defined as a multiphysics, multiscale model in which a digital model, such as a building information model (BIM), is updated based on data obtained from a physical system, such as sensor data, results from probabilistic simulations, and material/structural models. This study describes sensor data integration within a BIM as the first critical step toward the implementation of DTs to support structural health monitoring (SHM). In particular, the study defines a methodological approach used to integrate the as-built geometry of existing buildings, as well as their material properties and sensor data into a digital model to assist in accessing sensor data to assess a building’s structural performance. A mass-timber structural system consisting of post-tensioned cross-laminated timber (CLT) self-centering shear walls at the George W. Peavy Forest Science Center (“Peavy Hall”) at Oregon State University was used as a case study to test the proposed approach. The BIM of the shear walls was developed using a Scan-to-BIM approach by converting light detection and ranging point clouds into a BIM. Sensors in the building recorded environmental and structural parameters influencing the long-term performance of the shear walls. Measurands included relative humidity, air and wood temperature, wood moisture content, displacements, and deformations of shear walls. The precise placement of these sensors and the possibility to associate the measured parameters of these entities within a BIM is hypothesized to assist with data management by adding a spatial element to data and analysis results. In addition, the integration into the IFC-BIM platform of a material- and phenomena-specific warning tool allows to promptly identify areas of concern in the monitored building. This can support facility managers in planning inspection and maintenance activities and eventually could lead to the prolonged service life of a building.

Experimental investigation of the lumber-plybamboo-lumber screwed connections used in midply shear walls

Common midply shear walls constructed with wood-based mid-sheathing panels and nails usually exhibit substantial sheathing edge-tear and nail withdrawal failures, which will significantly limit the midply shear wall performance. This paper introduces an approach to prevent these connection failures, namely employing plybamboo panel and wood screw as middle sheathing and fastener, respectively. A preliminary experimental study on six groups of lumber-plybamboo-lumber screwed (LPLS) connections extracted from such improved midply shear walls were conducted, taking account of variables in terms of sheathing thickness and loading direction to the framing grain. Another three groups with Oriented strand board (OSB) mid-sheathings were tested for comparison. Test results show that the combined use of plybamboo panel and wood screw in the LPLS connections can effectively reduce the sheathing edge-tear and fastener withdrawal failures, and results in an over 70% increase in ultimate strength in comparison to the double-shear nailed connections with wood-based sheathing. However, the LPLS connections showed no advantage in elastic stiffness and ductility compared to the double-shear nailed connections with wood-based sheathing. The ultimate strength and ultimate displacement of the LPLS connections subjected to cyclic loading are 1.0–25.8% and 39.1–58.2% less than those of monotonically loaded connections, respectively, due to premature screw fatigue. The European Yield Model can reasonably predict the failure mode of the LPLS connections, but will underestimate the ultimate strength by 12–44%, probably due to underestimating the plybamboo embedment strength and ignoring the friction between plybamboo sheathing and SPF lumbers. The combined use of plybamboo panel and wood screw has great potential of being used in wood construction.

Effect of the Size of Multiple Perforations on the Performance of Long Reinforced Concrete Shear Walls

This paper investigates the effect of the size of multiple openings on the behavior of shear walls. In this study, the wall span is 24 m, the wall depth is 4 m, and is 0.3 m thick. The work involves the discussion of the three main kinematic and strength indicators that influence the shear wall performance. They are the load displacement relationship for the wall top edge, the equivalent concrete stress flow within the body of the wall, and the bending stress gradient at the bottom of the wall. The wall is constructed of reinforced concrete. A nonlinear finite element push over analysis has been carried out using Ansys software. The element Solid65 presented by Ansys effectively simulates the true behavior of concrete. The steel reinforcement has been modeled by link180 element. Primarily a finite element model for the solid bearing RC shear wall has been constructed and analyzed. The primary step has involved calibration and validation of the finite element model. Thereafter, pushover analysis has been performed for four perforated walls of various opening sizes. The study has indicated that when the percentage of the sum of the perforations’ areas to the total wall area surpasses 8.35%, the shear wall load carrying capacity starts to degrade. When the percentage of the sum of perforations surpasses 16.7% of the total wall area, the shear wall behavior starts to convert to that of two coupled shear walls. The larger the opening size is, the higher the stresses are, and the less the wall load carrying capacity is. When the percentage of the sum of the perforations’ areas to the wall total area surpasses 25%, the behavior of the shear wall converts to that of a frame. The study recommends that further future studies should be carried out on the effect of providing CFRP sheets on the edges of the openings, especially at lower stories in order to control concrete cracks at the edges of the perforations resulting from the developed large concrete equivalent stresses.

Experimental Study on the Seismic Performance of Shear Walls with Different Coal Gangue Replacement Rates

To replace conventional concrete with coal gangue concrete in the construction industry, lateral cyclic loading tests were applied to three shear walls with different coal gangue replacement rates in this study, in which the replacement rate of coal gangue was 0%, 50%, and 100%. The load-displacement hysteretic curves and backbone curves of the shear walls obtained from tests were analyzed to compare the failure process and seismic performance of each shear wall. The results indicate that the stress performance and failure morphology of coal gangue concrete shear walls and conventional concrete shear walls are extremely similar, and the characteristics of the hysteretic and backbone curves are approximately the same. With the increase in the coal gangue replacement rate, the bearing capacity and ductility of the three shear walls gradually decrease, the strength degradation gradually becomes significant, and the energy dissipation capacity becomes worse, but the difference is not obvious, and all of them can meet the requirements of seismic performance. In addition, with the increase in the coal gangue replacement rate, the stiffness degradation gradually slows, so it is feasible to construct a shear wall using coal gangue concrete instead of conventional concrete.

Influence of shear depth on seismic performance of shear wall reinforced with BFRP bars: mesoscale modelings

Influence of shear depth on seismic performance of shear wall reinforced with BFRP bars: mesoscale modelings

Seismic performance of precast shear wall of insufficient grouting material strength strengthened with steel plate

The sleeve-connected precast shear wall is used widely in engineering practice due to its high engineering quality and environmental protection. However, the insufficient grouting material strength due to negligent management affects greatly the mechanical properties of the precast shear walls. Three different strengthening methods of steel plate were proposed, and the seismic performance of the shear walls was studied under the horizontal low-cycle repeated loading. Results demonstrated that the extension of the cracks of the shear walls strengthened with steel plate was limited effectively and the damage degree was reduced significantly. The failure characteristic of the first crack in the shear walls was revealed. The peak load of the specimen with insufficient grouting material strength (CPSW) was 80.05% of the specimen with normal grouting material strength (NPSW). The cracking and peak loads of specimens strengthened with different methods (CPSW-R1, CPSW-R2, and CPSW-R3) were improved significantly, and the ductility of shear walls was 108.9%, 102.7%, and 100.7% of the specimen NPSW, respectively. The stiffness and energy dissipation capacity of the shear walls strengthened were restored to the level of the specimen NPSW. The results of this paper could provide some insight into the strengthening and maintenance of shear walls with insufficient grouting material strength.

Experimental and Analytical Lateral Performance of Shear Walls with Variable Phases of Deformation

Experimental and Analytical Lateral Performance of Shear Walls with Variable Phases of Deformation

A Comprehensive Study on the Effect of Regular and Staggered Openings on the Seismic Performance of Shear Walls

Shear walls have high strength and stiffness, which could be used at the same time to resist large horizontal loads and weight loads, making them pretty beneficial in several structural engineering applications. The shear walls could be included with openings, such as doors and windows, for relevant functional requirements. In the current study, a building of G + 13 stories with RC shear walls with and without openings has been investigated using ETABS Software. The seismic analysis is carried out for the determination of parameters like shear forces, drift, base shear, and story displacement for numerous models. The regular and staggered openings of the shear wall have been considered variables in the models. The dynamic analysis is carried out with the help of ETABS software. It has been observed that shear walls without openings models perform better than other models, and this is in agreement with the previous studies published in this area. This investigation also shows that the seismic behaviour of the shear wall with regular openings provides a close result to the shear wall with staggered openings. At the roof, the displacement of the model with regular openings was 38.99 mm and approximately 39.163 mm for the model with staggered openings. However, the model without a shear wall experienced a displacement of about 56 mm at the roof. Generally, it can be concluded that the openings have a substantial effect on the seismic behaviour of the shear wall, and that should be taken into consideration during the construction design. However, the type of opening (regular or staggered) has a slight effect on the behaviour of shear walls.

Mechanisms and Prediction Model of Load-carrying Capacity in Staggered Perforated RC Flanged Shear Walls

In order to understand the loading path and further anticipate the bearing capacity of the staggered perforated RC flanged shear walls, this paper proposed an improved strut-and-tie model and perforated reduction coefficient based on the theoretical and numerical analysis. The finite element model has been validated experimentally. The parametric study was conducted numerically to investigate the influence of shear-span ratio, axial compression load ratio, flange, dimension of perforation, and the additional rebar on the seismic performance of shear walls. When the ratio of perforation area to the wall is ranged from 10% to 26%, the proposed strut-and-tie model can effectively predict the loading path and the lateral ultimate bearing capacity with the different combinations of shear-span ratio and axial compression load ratio; however, if the ratio of the perforation area is either lower than 10% or higher than 26%, the proposed strut-and-tie model is not applicable. While the perforated reduction coefficient can be used to calculate the lateral ultimate bearing capacity of the perforated shear wall.

Experimental study on seismic performance of resilient recycled aggregate concrete shear walls

A type of recycled aggregate concrete shear wall was proposed in this work, which used the painted ultra-high-strength steel (UHSS) reinforcements with low bond strength and high yield strength in the boundary elements. For investigating the seismic resistance and resilient performance of this shear wall, six shear walls with the shear-to-span ratio of 1.5 were fabricated and tested under the cyclic loads. The variables studied in this paper were the types of the longitudinal reinforcement in the boundary elements, the existence of steel fibers, the presence of the concealed bracings (X-shaped) and the different axial compression ratios. The test results indicated that specimens with the UHSS reinforcement in the boundary elements decreased the residual deformation substantially and improved the resilient properties. The higher axial compression ratio enhanced lateral force resistance of shear wall but aggravated concrete damage which was adverse to the resilience. In addition, the utilization of steel fibers in concrete significantly reduced the crack width. The shear wall including concealed bracing not only showed much higher lateral force resistance, but also had desirable resilient performance under the large deformation. Finally, a simplified calculation model for such shear walls was proposed on the basis of experiment. And the good accuracy of the calculation model was verified by comparing the calculation results and the measured results.

Experiment and numerical analysis on seismic performance of resilient shear walls using high strength recycled aggregate concrete

In this paper, ultra-high strength bars (UHSB) was innovatively applied to the high-strength recycled aggregate concrete (RAC) shear walls to achieve resilient performance. In order to explore the resilient and seismic performance of the shear wall, five specimens with shear span ratio of 2.2 were tested under cyclic loading. The variables also included the type of longitudinal reinforcement in boundary elements, the presence of anti-corrosion coating in UHSB and the replacement ratio of recycled coarse aggregate (RCA). The results showed that the use of UHSB in the boundary elements significantly improved secondary stiffness and reduced the residual displacement and residual crack width of the shear walls. The anti-corrosion coating decreased bond strength between UHSB and RAC, but it had negligible effect on the seismic and resilient performance of the specimens before 2% drift ratio. Increasing replacement ratio of RCA slightly decreased the lateral force of the specimens under the same drift ratio, but the walls represented satisfactory resilient performance. In addition, finite element models were established in ABAQUS, and the effect of UHSB bond performance, the strength of longitudinal reinforcement with anti-corrosion coating, and the substitution rate of UHSB were analyzed. The results showed that the numerical analysis results were in good agreement with experiment results.

Flexural retrofit of existing reinforced concrete structural walls with various boundary element details under cyclic loading

A recent regulation in Korea allows the rehabilitation of aging apartment buildings, with vertical extensions up to three floors. To satisfy the increased flexural strength requirement, a method that places vertical reinforcements and re-casts concrete after crushing the boundary elements is proposed. In this study evaluates the flexural performance of shear walls to which the boundary element retrofit method was applied. Six real-scale specimens were fabricated and reversed cyclic loading tests were performed. The experiments showed that the flexural strength increased as the vertical rebar ratio of the boundary element increased. As the development length of the post-installed rebar was reduced, the anchorage of the rebar was effective. When using shear studs to connect the existing and the retrofitted wall, the flexural strength was similar; however, the deformation due to shear was controlled. It was confirmed that a discontinuous strain distribution occurred. Based on the experimental results, a flexural design model under limited conditions was proposed, which accurately predicted the flexural strength. However, because there is a tendency to overestimate the tensile rebar strain, future studies should develop a flexural design model that can make a more accurate prediction by further analyzing the variables affecting the boundary element retrofit method.

Flexural Behavior of Lightweight Aggregate Concrete Shear Walls with Boundary Element

AbstractThis study examined the effects of the unit weight of concrete (ωc) on the flexural performance of shear walls with different amounts (Ash) of transverse reinforcement in the boundary eleme...

Experimental Study on a Low‐Rise Shear Wall with the Built‐In Shear Steel Plate

In this paper, a new reinforcement scheme is proposed to improve the seismic performance of low‐rise shear walls. The new system combines the advantages of slotted and composite shear walls to exhibit a high bearing capacity and good deformation performance. Two low‐cycle repeated loading tests with different forms of shear walls were conducted to accurately understand its seismic performance. Seismic performance indexes, such as failure mode, bearing capacity, hysteresis curve, stiffness degradation, and energy dissipation capacity, of the new shear wall under the low‐cycle reciprocating load were obtained to verify its reliability. The results show that the newly reinforced shear wall has two clear seismic defense lines. Its deformation and energy‐dissipation capacities and lateral stiffness stability are greatly improved compared with traditional low‐rise shear walls. Thus, the proposed method can provide a new means for enhancing the seismic performance of shear walls.

Seismic Performance of Assembled Shear Wall with Defective Sleeve Connection

In this paper, three kinds of shear walls with full sleeve grouting, fully defective sleeve and partially defective are designed for finite element analysis to analyze the influence of defects on the seismic performance of shear walls. The research shows that at the beginning of loading (5 s), the three models begin to appear compressive damage at the bottom of the wall in all three models. The damage of the defect-free model develops rapidly, and the damage of the fully defective model is basically the same as that of the partially defective model. With the gradual increase of displacement control (15 s), the compressive damages at the foot of the wall in the defect-free and partially defective grouting model are obvious, with plastic hinge formed in the foot of the wall, and the phenomenon of development along the pier body showing up. When the structure is damaged, the overall compressive damages of the wall in the defect-free and partially defective models are obvious, and the damage on the defective side of the partially defective model is slightly deficient. While the maximum stress of pre-stressed reinforcement in the defect-free model is concentrated at the top of the sleeve, the maximum stress of the pre-stressed steel bar in the fully defective model appears at the end of the steel bar in the sleeve. The hysteresis curve shape of the non-defect model and partially defective model are basically the same, showing a “shuttle” shape with a sound energy dissipation effect. The hysteresis curve shape of the fully defective model appears an obvious “pinch” phenomenon. The yield displacement levels of the defect-free and partially defective models are smaller than that of the fully defective model structure. The stiffness degradation curves of the three models basically overlap with one another. Before the limit displacement, the stiffness results of the non-defect model and the partially defective model are greater than that of the fully defective model. When the displacement is loaded to 20 mm, the stiffness degradation of the three models is equivalent.