Behavior Of Shear Walls Research Articles

Test on Shear Behavior of Double-Sided Thin Steel Plate Shear Wall Filled with Rigid Polyurethane Foam

A double-sided thin steel plate shear wall filled with rigid polyurethane foam (SWR) is proposed. A quasi-static monotonic loading test and quasi-static cycling loading test on shear behavior and the energy dissipation capacity of the SWR were carried out. Four kinds of test specimens, including the pure steel frames, the steel frame with double-sided thin steel plates, the SWR, and the SWR with an open hole, were tested. The results showed that compared with the pure steel frame, the erection of thin steel plates on both sides enhances the shear bearing capacity, initial shear stiffness, and energy consumption capacity. It turns out that the rigid foam polyurethane (RPUF) significantly increases the shear performance of the thin steel plate shear wall. The main reason for this is that the bond effect and support effect of the RPUF delay the out-of-plane buckling of thin steel plates and improve shear performance and energy dissipation capacity.

Modelling of CFRP-Strengthened RC Shear Walls with a Focus on End-Anchor Effects

This study first provides an overview of the development of a novel tube anchor system for the seismic strengthening or repair of reinforced concrete (RC) shear walls with carbon fibre-reinforced polymer (CFRP) sheets. The new anchor system can significantly improve the load transfer mechanism between the CFRP and supporting RC structural elements, resulting in ductile behaviour of the strengthened shear walls with increases of lateral load capacity and ductility by up to 2.6 and 8.3 times, respectively. The study then presents a new finite element modelling technique capable of capturing the complete cyclic response, i.e., from the elastic behaviour to the ultimate collapse of CFRP-strengthened RC shear walls with the newly developed tube anchor system. Two different modelling approaches are proposed to consider the effects of the tube anchor system. Additionally, other important CFRP- and RC-related mechanisms, including CFRP debonding effects, confinement enhancement, tension stiffening, compression softening, and strength and stiffness degradation under cyclic loads, are also considered in the model. By comparing the analytical and experimental results, it is demonstrated that the proposed modelling approach can accurately replicate the complex behaviour of CFRP-strengthened shear walls with a wide range of aspect ratios, from the ductile flexural behaviour of slender walls to the brittle shear failure of squat walls, without requiring detailed modelling of the anchor system.

Seismic performance assessment of precast RC shear wall structure with lead viscoelastic damper

The precast reinforced concrete (RC) shear wall structure with lead viscoelastic damper is a combination of shear wall with horizontal connectors and vertical energy-dissipating connectors. The lead viscoelastic damper (LVED) is adopted as the vertical wall-wall joint to increase the plastic deformability of shear wall and provide additional strength and energy dissipation. The pore-forming grouted lap-sliced connector is adopted as the horizontal wall-floor joint to ensure the overall seismic performance of the shear wall. Firstly, cyclic loading tests were conducted to investigate the influence of lead and viscoelastic layer thickness on the hysteretic behaviour of LVED, and the theoretical method and finite element analysis model for LVED were also proposed and validated by the test results. Additionally, the seismic behaviour of precast shear walls with and without LVEDs was studied experimentally and numerically. It was shown that better cooperative working performance was observed in the precast shear wall with LVED. Finally, the dynamic responses of precast frame-shear wall structure adopting LVED was investigated based on dynamic time-history analysis.

Numerical modeling of seismic behavior of ellipse and peanut-shaped auxetic steel plate shear walls

This study proposes a new auxetic-shaped steel plate shear walls (simply referred to as ASSPSWs) consisting of boundary members and built-in perforated infill plates. The connection type between the boundary members is a hinge joint. The hole forms on the infill plates include orthogonal ellipse-shaped (ASSPSW-OE) and orthogonal peanut-shaped (ASSPSW-OP). This paper studied the hysteretic performance of two steel plate shear walls’ types based on the finite element analysis method. Within the study context, a parametric analysis was carried out to investigate the influence of various factors, such as hole size and hole distance, on the seismic performance of steel plate shear walls (SPSWs). The results indicated that reducing the the ratio of the ligament thickness to ellipse major axis (t/D) in orthogonal ellipse-shaped SPSWs can effectively increase the porosity while reducing the bearing and energy dissipation capacities. Under the condition with the t/D unchanged, increasing the ratio of the major to minor axis of the ellipse (d/D) raises the porosity and does not significantly reduce the bearing capacity and energy dissipation capacity of the SPSWs. For orthogonal peanut-shaped SPSWs, the holes’ geometrical parameters significantly influence the hysteretic performance. Particularly, with the increase in the radial ratio of large to small circles in a peanut-shaped hole (R/r), the spacing between cells decreases. When drift exceeds 2%, the equivalent viscous damping ratio decreases sharply. Unlike the orthogonal ellipse-shaped SPSWs, changing the arrangement angle of peanut-shaped cells has no significant effect on orthogonal peanut-shaped SPSWs. However, the larger the angle, the greater the out-of-plane buckling of orthogonal ellipse-shaped SPSWs; thus, the energy dissipation capacity is reduced. The similarities lie in that the larger cell arrangement angle will make the steel plates have a complete stress field, and the bearing capacity will be slightly improved. When the cell arrangement angle (θ) is 45°, the SPSWs can develop high initial stiffness.

Determination of piers shear capacity using numerical analysis and machine learning for generalization to masonry large scale walls

In this study, comprehensive investigations were conducted on the structural behavior of masonry shear walls considering both aspect ratios and the axial forces. A reliable and simplified macro approach called Multi Pier (MP) method was employed to analyze single masonry piers with different aspect ratios (h/l). The shear and flexural strength along with the failure mechanism of each pier were obtained versus various levels of axial force during the sensitivity analysis. The results of the analysis were used as an input of a machine learning approach called Back Propagation Multi-Layer Perceptron (BPMLP) to generalize the data. The outcomes of machine learning was utilized to develop simple, but accurate equations as well as a user-friendly application to obtain the shear strength of a masonry pier according to the mechanical and geometrical properties. The BPMLP network is also able to produce and estimate all potential failure modes of a masonry wall. Finally, the efficiency of the proposed equations and developed application was evaluated using a novel macro-element approach. It is concluded that the proposed equations can be used in any macro-elements approach to enhancing efficiency and saving time. The proposed Equivalent Wall (EW) model was able to precisely estimate the response of full-scale façade masonry walls subjected to the in-plane loads. According to this model, each pier and spandrel was substituted by two elastic continuous (2D) macro-elements which connected via two bi-component discrete elements. A linear behavior based on masonry modulus of elasticity and bi-linear constitution according to the shear strength was assigned to the axial and shears components of the discrete links, respectively. The proposed EW model was verified using a five-story-seven-bay masonry wall. Satisfactory results were observed in terms of global load-deflection behavior comparing with popular approaches from the literature.

Parametric study on lateral behaviour of composite shear walls with high-strength manufactured sand concrete

The traditional reinforced concrete (RC) shear wall showed limited seismic performance under extreme earthquakes when deployed at the bottom of high-rise buildings, due to the presence of high axial compression ratios. In this study, a novel composite shear wall was proposed to improve the seismic performance at high axial compression ratios, in accordance with recent demands for eco-friendly materials. The novel composite wall integrated the high-strength manufactured sand (MS) concrete, ring-stirrup and steel tube to fully maximize material efficiency and achieve inter-enhancement. A quasi-static test was at first carried out on the proposed composite shear wall, which validated the expected enhancement on its lateral mechanical behaviour preliminarily. On this basis, a refined finite element (FE) model was established for the test specimen by considering the nonlinearity and cyclic behaviour of materials, in order to provide further insights into its behaviour under lateral loads. The established FE model was verified against the test data, which showed a good agreement between the numerical prediction and the test result. Meanwhile, a list of key parameters was identified according to their influence on the lateral behaviour of the composite wall, including the axial compression ratio, yield strength of steel tubes, compressive strength of concretes, reinforcement ratio in concrete-filled steel tube (CFST) columns, and space between ring-stirrups. On this basis, a series of parametric investigations were carried out with the validated FE model, by varying the selected key parameters. In general, the research output offered a constructive guideline and data support for the expected engineering application of the proposed composite shear wall.

Seismic behavior of steel-plate encased concrete shear wall with paralleled circular CFST columns: Laboratory test and numerical simulation

Aiming to improve the structural behavior of high-rise buildings, a steel-plate encased concrete shear wall with parallel circular concrete-filled steel tube columns (P-CFST-SCSW) is proposed and investigated by experiments and numerical studies in this study. All seven specimens were conducted and tested under reversed cyclic force to explore the influences of different design parameters, including axial compression ratios, steel tube thicknesses, spacing-thickness ratios, and shear span ratios. The failure modes, hysteresis behavior, strength and stiffness degradation, energy dissipation were thoroughly recorded and compared in detail. Results indicated that all specimens have experienced the failure process of boundary steel tubes buckling, steel plates buckling and concrete crushing. Results also showed that the bearing capacity and deformation capacity of proposed composite walls was excellent. The peak force and initial stiffness of P-CFST-SCSWs were improved by reducing the shear span ratio and increasing the axial compression ratio, while the stiffness degradation and ductility quickly deteriorated. The increased thickness of circular steel tubes considerably improves the seismic behavior of P-CFST-SCSWs. Finally, the numerical model was established to further investigate the effect of the concrete strength, steel yielding strength, and circular CFST columns number on lateral behavior of P-CFST-SCSWs.

Nonlinear analysis of planar, H-shaped and U-shaped thin reinforced concrete shear walls

This paper presents and discusses the results of nonlinear finite element analysis (NL-FEA) of thin reinforced concrete shear walls. For this, an in-home developed shell structures NL-FEA program called CANECA was used. The materials modeling use the basis of the Modified Compression Field Theory and the geometric nonlinearity is evaluated using a Total Lagrangian Formulation. The influence of geometric nonlinearity and cyclic loading condition on an H-shaped shear wall behavior is discussed. From the obtained results, a higher influence of the cyclic loading condition is observed. Other two shear walls (simple planar and U-shaped) are also analyzed. Their geometry and reinforcement are modified in order to observe the influence of these parameters on the structural behavior, including the case of slender shear walls. The performed analysis on the two shear walls showed good agreement with the numerical response obtained in the NL-FEA program VECTOR4. The obtained numerical ultimate loads were much higher than the original structure design load and the slenderness ratio was insufficient to characterize the ultimate structural behavior. The results from this study can contribute for a better understanding on the structural behavior of thin reinforced concrete shear walls, and serve as guidance for future studies and normative developments.

Experiment study on seismic behavior of squat UHPC shear walls subjected to tension-shear combined cyclic load

Five squat UHPC shear walls with high axial tension ratio ranging from 0.5 to 0.6 were tested under tension-shear combined cyclic load to replicate seismic performance of bottom shear walls in high-rise buildings. All specimens exhibited shear-sliding failure mode characterized by multiple shear-related cracks distributed in a dense array and full-length localization of horizontal crack along the end of anchorage rebars. The seismic behaviors were comprehensively evaluated by hysteretic responses, energy dissipation capacity, strength and stiffness degradation. Additionally, detailed analysis on the strain development of vertical reinforcement and web horizontal rebars were carried out to study their shear resistance contribution. It was found that, with the assistance of steel fibers providing an efficient shear resistance consistent with the varying direction of principal tensile stress, the shear capacity of UHPC shear wall was slightly improved even when axial tension ratio increased to 0.6. The ultimate drift capacity of UHPC specimens reached 3.3% drift with an excellent strength retention ability of more than 500kN in this test. Besides, the accumulated energy consumption of UHPC specimen after crack localization improved by 38% compared with the normal concrete shear wall. Results of strain analysis demonstrated that vertical reinforcement provided an effective clamping force in the shear-sliding resistance. A modified design formula considering efficient tension resistance offered by UHPC was proposed with adequate safety concerns and accuracy.

Seismic behavior of CFRP-steel composite plate shear wall with edge reinforcement

In this paper, a CFRP-steel composite plate shear wall structure with the laying method of bolted connection plate is proposed. A theoretical model of CFRP - steel composite plate shear wall is formulated. The effectiveness of the design method is verified by the shear experiment of the connection. Subsequently, two 1/3-scale steel plate shear wall(SPSW) specimens are tested under a low cyclic load. Compared with the pure SPSW, the ultimate bearing capacity, stiffness, and energy dissipation capacity of the CFRP-steel composite plate shear wall are improved by 23%, 7.7%, and 4.2%, respectively. The finite element analysis agrees well with the experiment curves, and the failure mechanism in the CFRP-steel composite plate shear wall structure can be well understood. Finally, the effects of different CFRP laying layers, fiber orientation angles and aspect ratios on the performance of SPSW are compared and analyzed. Increasing CFRP laying layers and aspect ratios will improve the bearing capacity and energy dissipation capacity, but when the thickness of CFRP is too large, the ductility performance will be reduced. When the aspect ratio is too large, the stress distribution is not uniform, the angle deflection of the tension field is more serious, and the performance development is not sufficient. An aspect ratio of 1–1.5 is recommended to use in practical engineering applications. Increasing the orientation angles between CFRP and the tension field can improve the ductility and energy dissipation capacity. When there is a multi-layer laying design, it is recommended to consider multi-orientation angle laying.

Experimental Study on Seismic Behavior of Lightweight Concrete-Filled Cold-Formed Steel Shear Walls Strengthened Using Horizontal Reinforcement

ABSTRACT To improve the seismic behavior and thermal property of traditional cold-formed steel (CFS) walls for satisfying the requirements multistory structures, a new type of fiber-reinforced lightweight concrete (FLC)-filled CFS shear wall strengthened using horizontal reinforcement is proposed in this study. Four full-scale specimens were tested under reversed cyclic loading to investigate the seismic behavior, including failure mode, hysteresis curve, shear capacity, deformability, stiffness degradation, and energy-dissipating capacity. Test results indicated that the restrictive effect of FLC on the studs and its diagonal-bracing effect improved the wall’s hysteretic behavior, making the wall exhibit the ductile shear failure. Increasing the wall thickness increased the shear strength, lateral stiffness, and energy-dissipating capacity, whereas installing the coupling-section interior studs enhanced the ductility. Finally, a simplified strut-and-tie model was proposed to evaluate the shear capability of FLC-filled walls, and the calculated values exhibited good agreement with the test results, but the further verification is required.

Seismic performance evaluation of steel and GFRP reinforced concrete shear walls at high temperature

Fire-induced structural damage to the seismic performance of reinforced concrete shear walls is critical in the event of a fire-earthquake scenario. However, only few researchers have studied the seismic performance of reinforced concrete shear walls at high temperatures. This study focuses on the seismic performance of fiber reinforced concrete shear walls at high temperatures by using finite element (FE) software, ABAQUS. The experimental test available in a literature on seismic behavior of shear walls exposed to fire and thermal properties of glass fiber reinforced polymer (GFRP) bars were used to validate the FE model and showed good agreement and thus used in the simulation.The FE results showed that exposure of RC shear wall to fire reduced the strength of the wall. The strength of walls at the maximum applied drift of 3.2% with concrete cover thicknesses of 20 mm, 25 mm, and 30 mm was dropped by about 70%, 76%, and 85% of the reference shear wall, respectively. Similarly, the strength of RC walls was reduced by about 80%, 75%, and 68% of the reference shear wall for the duration of fire exposure of 30 min, 60 min, and 120 min, respectively. Additionally, the strength of walls due to one side, two sides, or all sides’ exposure to fire was decreased by about 68%, 56%, and 50% of the reference shear wall, respectively. It can generally be concluded that the fire exposure sides has largely affected the strength of the shear wall compared to the other parameters and GFRP bars were more sensitive to temperature than steel bars.

Eccentric behavior of l-shaped Multi-partition Steel-Concrete composite shear walls

An l-shaped composite shear wall, comprised of a multi-partition steel tube and concrete, is developed to improve the behavior of the l-shaped component. It possesses high load-resisting strength and good ductility as it makes better use of steel and concrete. Eleven samples were tested under eccentric load to determine the impacts of the depth, breadth, and load angle. The experimental results showed that the eccentric strength of the specimen under a load angle π was higher than that of the specimen under a load angle of 0. The specimens failed in out-of-plane and in-plane flexural modes when the depth-to-width ratios were different. Then, the finite element (FE) model using an improved constitutional relation of concrete was established to analyze the eccentric mechanism of the l-shaped composite shear walls. Furthermore, parametric analysis using the FE model was taken to determine the key factors of eccentric behavior. Compared to the design methods specified in EC4, AISC, and CECS, it was found that the calculated capacity for the stub was underestimated while the calculated capacity of the slender components was overestimated. The simplified formulas were presented for predicting the N-M curves based on the experimental and FE analysis and it could conservatively include the influence of the load angle and the relative slenderness.

Experimental and numerical investigation on the seismic behaviors of RC shear walls with multiple post-openings before and after strengthening by steel plates

In this paper, the quasi-static tests of seven RC shear walls and the corresponding finite element simulations were carried out to investigate the seismic behaviors of the RC shear walls with multiple post-openings before and after being strengthened by bonding steel plates, including failure modes, bearing capacities, ductility, energy dissipation capacities, structural performance levels, and also the strain distribution of the rebars. The detail arrangements of the post-construction openings are taken into account, on the premise of the same total area of the openings. Not only in the tests but also in the simulations, there is one RC wall with a single post-opening in the center of the wall, one RC wall with two post-openings that are horizontally arranged at the mid-height of the wall, and one RC wall with two post-openings which are vertically arranged at the mid-length of the wall. In addition, other three specimens, with the same opening arrangements as the three types of RC walls motioned above, strengthened by bonding steel plates around the openings, and one shear wall without openings for reference were fabricated. The results showed that the failure modes of reinforced or unreinforced RC shear walls with post-openings are shear failure and flexural shear failure respectively. The seismic bearing capacities of the shear walls with post-openings can be obviously recovered, up to 33.5%, by bonding steel plates. Moreover, the ductility coefficients of those strengthened RC walls were also improved, in the range of 5.6% to 58.1%.

Cyclic loading test and lateral resistant behavior of flat-corrugated steel plate shear walls

Corrugated plate shear walls (CPSWs) can achieve large initial lateral stiffness, high resistance, and good energy dissipation capacity. However, severe post-buckling resistance degradation of the infill corrugated panel compromises the lateral resistant behavior of CPSWs with a large width-to-height ratio. To solve this problem, this paper proposed an innovative flat-corrugated steel plate shear wall (FCPSW), in which the infill panel is composed of a middle trapezoidal corrugated steel plate and two flat steel plates covering both sides by bolts. Cyclic loading tests were carried out for a FCPSW specimen and a CPSW specimen, to reveal the hysteretic behavior, failure mode and the restraining mechanism between the corrugated plate and the flat plates. Then, finite element analysis (FEA) was adopted to simulate the tests and investigate the effect of key parameters on the lateral resistant behavior of the infill flat-corrugated panel in FCPSWs under cyclic loading. The study showed that, the infill flat-corrugated panel utilized the interaction between the corrugated plate and the flat plates, to effectively reduce the out-of-plane buckling deformation and improve the lateral performance. The normalized residual resistance of the FCPSW specimen can be increased by 50% compared to the ordinary CPSW specimen. The material yield stress, the bolt spacing, the corrugation length, the corrugation inclined angle and the thickness ratio of the infill plates were the key factors affecting the hysteretic performance of the flat-corrugated panel, while effects of the width-to-height ratio and the corrugation ratio was reduced compared to the conventional CPSWs. The design suggestions proposed can avoid unstable post-buckling behavior of the infill panel in FCPSWs and provide a simple and feasible method in the preliminary design.

Cyclic response of precast concrete shear walls with reduced grouted sleeves or corrugated metallic duct splices

The structural behavior of precast concrete shear walls (PSWs) is highly dependent on their vertical connections. Current PSWs mainly use two-row (paired) connections, which is relatively time-consuming and involves high cost and construction difficulties on wall assembly. Reducing the number of vertical connections from two-row to one-row or even partial could be economical and efficient solutions for the use of PSWs in practice. Reversed cyclic tests on seven full scale shear wall specimens were conducted under the axial compression ratio of 0.24. Grouted steel sleeves (GS) and grouted corrugated metallic duct (CMD) connections were used in the test program, considering three different layouts: two-row, one-row and partial. Test results showed that all shear walls failed by flexural-shear. The PSWs exhibited more and plumper hysteretic curves than the monolithic wall. The load carrying capacity of PSWs was close to the monolithic wall with an average difference of less than 7 %. The displacement ductility coefficients of the PSWs with two-row, one-row and partial GS were 2.5, 2.8 and 2.6 respectively, which were slightly higher than that of the monolithic specimen (2.2). The ductility of the PSWs with CMD were2.3, 2.9 and 2.3. It was also indicated that PSWs with GS or CMD connections had greater energy dissipation capacity than the monolithic shear wall. The decline in stiffness and energy dissipation capacities of all precast specimens were similar.

Seismic behavior and nonlinear analysis of Hybrid Coupled Shear Walls

Hybrid Coupled Shear Walls are an innovative seismic-resistant system that aims at merging the advantages of the classical Coupled Shear Walls with the dissipative capacity and easy-to-repair characteristics of steel elements. They are constituted by a reinforced concrete wall connected to two side steel columns by dissipative steel links. Depending on the stiffness/strength of the links, it is possible to obtain different distributions of the seismic forces between the wall and the columns. As resulting from previous research activity on this topic, the seismic behavior of this structural system can be strongly influenced by the higher modes, especially for mid/high-rise buildings, making classical pushover analyses unable to catch the correct behavior. In this regard, the paper presents the comparison between the results of Incremental Dynamic Analyses and of different Pushover Analyses, giving indications about a more reliable procedure for the assessment of the seismic performance through suitable pushover analysis.

Experimental investigation on the lateral performance of CLT shear walls connected to perpendicular walls

Typically, the mechanical behavior of CLT shear walls for lateral loads is assumed to be governed by the wall base connections, such as hold-downs and angle brackets. However, many experimental and numerical studies available in literature have shown that in “box type” CLT buildings, the connections between perpendicular walls contribute to the lateral response of the CLT shear walls. This study presents the results of an experimental campaign aimed at investigating the lateral performance of CLT shear walls connected to perpendicular walls. Two CLT wall assembly configurations were tested: single Shear Wall configuration (SW), which considers a single CLT shear wall subjected to lateral load, and Shear Wall connected to Perpendicular Wall configuration (SW+PW), which considers a CLT Shear Wall connected to a Perpendicular Wall subjected to lateral load. Results showed that the SW+PW configuration reached higher structural performance in terms of lateral stiffness and lateral capacity than single SW configuration. This increase of lateral performances is governed by the properties of the wall-to-wall connections as well as the properties of the hold downs used in the perpendicular walls. Results of this experimental study show that the perpendicular walls and wall-to-wall connections may be included in the design models of CLT shear walls subjected to lateral loads.

A study on the effect of thickness and spherical diagonal for LYP Infill Plate of shear walls

One of the most significant parameters which should be considered by all engineers is improving structures’ strength subjected to lateral load. Steel shear wall whose duty is to affect lateral load (wind and earthquake) is a wall which consists of shear part. Application of low yield point (LYP) steel in shear walls allows the employment of moderate and/or stocky infill plates with low yielding and high buckling capacities, which can result in enhanced buckling stability, serviceability, and energy dissipation capacity of such systems. Infill LYP plate is used to improve shear wall behavior which leads to enhancement of stiffness. In the present research, infill plate with spherical appendages is applied, and its impact on plate stiffness, cyclic behavior and energy absorption are investigated. The spherical diameter has been chosen respectively 10 and 20 cm distributed with two patterns (diagonal and plus form). The best performance is for a LYP plate with a 10 cm spherical diagonal pattern.

Modelagem computacional de paredes de contraventamento de alvenaria estrutural considerando os efeitos de fissuração nas juntas de argamassa

Abstract: This study presents a computational model to analyze structural masonry shear walls behavior considering the effects of mortar joint cracking on loss of stiffness. The simplified equivalent frame model was used but including link elements between the frame node to simulate the effects of cracking. The analyses were conducted using the SAP2000 computer program and consisted of modeling four shear walls on a 1/3 scale which were experimentally assessed. The results indicated that the proposed computational modeling approach consistently reproduced the effects of cracking at mortar joints, accurately simulating the nonlinear behavior of masonry.