Shear Wall Model Research Articles

A Study on the Bearing Performance of an RC Axial Compression Shear Wall Strengthened by a Replacement Method Using Local Reinforcement with an Unsupported Roof

When compared with conventional replacement reinforcement methods, the method of replacement using a local reinforcement with an unsupported roof has the advantages of shortening the reinforcement cycle and reducing material loss, and many scholars have carried out useful explorations thereof. At present, the formula for the bearing capacity of reinforcement by replacing concrete in the Code does not consider the effect of stress hysteresis on the parts of the reinforcement; so when the initial stress level is greater than 0.4, the Code’s strength utilization coefficient of 0.8 for the new concrete in the replaced area is on the side of insecurity. In this study, we are trying to improve and supplement the formula in the Code through the following work. Firstly, 18 groups of shear wall models were constructed using a VFEAP finite element analysis program to analyze the bearing performances of the shear walls after the replacement. The results showed that the replacement concrete strength, the initial stress level and the size of the replaced area had a significant influence on the bearing capacity of the shear wall after the replacement. Secondly, utilizing the replacement concrete strength, the initial stress level and the size of the replacement area as key parameters, then introducing the strength improvement coefficient considering the constraints of the stirrups, the modified strength utilization coefficient of new concrete in the replaced area was formulated. Finally, based on the modified strength utilization coefficient, the replacement bearing capacity formulas for the one-batch, two-batch, and three-batch replacements were derived, and an N-batch replacement bearing capacity formula was regressed and fitted on the basis of these equations, which are less discrete and more secure than the Code’s formula.

Experimental and numerical investigation of the cyclic behaviour of coupled balloon-type CLT shear walls with high-capacity base connections

Mass timber buildings have gained global popularity due to the increasing availability and affordability of mass timber products and an increasing awareness of the sustainability of timber construction. This paper presents an experimental and numerical study on coupled balloon-type cross-laminated timber (CLT) shear walls with the aim of overcoming the capacity limitations of platform CLT shear walls. Using self-tapping screws to create innovative hold-down solutions, three two-storey coupled CLT shear walls were cyclically tested and the results demonstrated that the proposed coupled wall systems could achieve significantly higher lateral strength (over 400 kN) and initial stiffness (up to 14 kN/mm) compared to platform CLT shear walls in literature. The cyclic test results were used to validate a finite element CLT shear wall model in CLTWALL2D. The calibrated model was then used to run a parametric study of a series of balloon-type CLT shear walls up to twelve storeys (42 m) in height. This study provided evidence that coupled balloon-type CLT shear walls with high-capacity screwed connections have the potential of reaching high strength and stiffness with the displacement ductility factor μ = 2–4.

Seismic performance of carbonated recycled aggregate concrete shear walls

The carbonated modification method is recognized as an effective method to enhance recycled aggregates (RA), but there is currently a lack of research on carbonated recycled aggregate concrete (CRAC) used for structural engineering. This paper investigated the impact of CRAC on the seismic performance of shear walls, quasi-static tests of one natural aggregate concrete (NAC) shear wall and four concrete shear walls with different replacement ratios (30 %, 50 %, 70 %, and 100 %) of carbonated recycled aggregate (CRA) were conducted. The ductility, energy dissipation, stiffness, strength degradation, and lateral displacement components of CRAC shear walls were evaluated. The results indicate that the seismic behavior of the shear walls degraded as the replacement rate of CRA increased. Based on the comprehensive evaluation of failure patterns and seismic performance, the replacement rate of CRA is suggested to be taken as 70 % in the concrete shear walls. Finally, the strut-and-tie model was validated as an effective method for predicting the shear capacity of CRAC shear walls, and the accurate softening coefficient constant C of the strut-and-tie model for CRAC and RAC shear walls was proposed.

Investigation of plastic hinge length in high-ductility reinforced concrete shear walls

In this study, the plastic hinge lengths of reinforced concrete (R/C) cantilever shear walls were analytically determined considering various design parameters. Nonlinear static (Pushover) analyses were conducted on R/C shear wall models and their nonlinear behavior was examined using ABAQUS software. In the study, 72 shear wall models with different parameters were analyzed under the influence of vertical and horizontal loads. Parameters whose effects on plastic hinge length were investigated height/length ratio (Hw/Lw), axial load ratio (N/No), and horizontal web reinforcement ratio (ρsh). The load-displacement graphs of the modelled shear walls were obtained. The plastic hinge height of shear walls was determined according to the heights of the deformations in the concrete and longitudinal steel reinforcement in the section when the shear walls lateral load decreased by 15%. The analytical plastic hinge lengths (Lpz) were determined with respect to the location of the yield occurred at the longitudinal steel reinforcement of the shear wall. The observed plastic hinge lengths (Lp) were determined based on the height of observed the crush as of the foundation top level in the concrete shear wall model. The relationship between the findings of this study and empirical formulas in the literature was determined. It was determined that there is greater closeness between the values obtained from empirical formulas in the literature and the observed plastic hinge length values. It was observed that the plastic hinge length generally increases as the shear span increases. It was observed that the change in ρsh was not a very effective parameter in plastic hinge formation. As the N/No decreases, the plastic hinge length values ​​ generally increase. The Lp/Lpz ratio varied within the range of 0.15-0.50. In addition to ductility (μ) values were determined by using the displacements determined according to both the crushing occurred in the shear wall concrete and the yield observed in the steel reinforcement. The observed that the ductility value depends more on Hw/Lw ratio as N/No ratio decreases.

Strength calculation method and numerical simulation of slender concrete shear walls with CFRP grid-steel reinforcement

A series of experimental research has demonstrated superior hysteretic behavior, damage mitigation, and self-centering properties of concrete shear walls incorporating CFRP grid-steel reinforcement. Developing comprehensive theoretical and numerical models becomes crucial to assess the performance of these novel walls for structural design and application purposes. Based on the preliminary experimental investigation, a strength calculation method and numerical model for slender concrete shear walls with CFRP grid-steel reinforcement were proposed in this study. The calculation method provided a stable estimation for the loading capacity and ultimate compressive strain of edge concrete for the slender CFRP grid shear wall. The fracture strain of outermost longitudinal CFRP grid and ultimate compressive strain of edge concrete were suggested for design. The numerical model integrated hybrid reinforcements and utilized MVLEM to simulate the nonlinear hysteretic behavior of CFRP grid shear walls, effectively considering specimen failure mechanisms. The model can well capture the hysteretic behavior of the specimen, involving the peak loading, envelope curve, residual deformation, and stiffness degradation. Finally, the parametric analysis was conducted to further investigate the effects of axial compressive ratio and aspect ratio on shear walls with CFRP grid-steel reinforcement.

Simplified Modeling Method for Prefabricated Shear Walls Considering Sleeve Grouting Defects

The sleeve grouting connection is the most common form of vertical connection for prefabricated shear walls. However, during construction, this type of connection is prone to defects such as insufficient anchorage length of reinforcement, deviation of reinforcement, and insufficient amount of sleeve grouting, which significantly impact the integrity and seismic performance of the prefabricated shear wall structure. The finite element analysis of the prefabricated shear wall with sleeve grouting connection is still based on solid element modeling. This method has the disadvantages of complex models and low computational efficiency. In this paper, a simplified modeling method for prefabricated shear walls considering sleeve grouting defects was proposed to address this issue. Firstly, the equivalent constitutive relationship of the sleeve grouting defect connector was constructed based on the uniaxial tensile test of the existing sleeve grouting defect connector, and the T3D2 element was used to simulate the sleeve grouting connector. Then, the mechanical behavior of the horizontal joint between the shear wall and the foundation beam was simulated by the cohesive force model, and the prefabricated shear wall models with sleeve grouting defects were established. The accuracy of the simplified modeling method was verified by comparing the experimental results and numerical simulation results of the seismic performance of the prefabricated shear wall with sleeve grouting defects. The results showed that the hysteresis curve, skeleton curve, and failure mode of the numerical simulation were in good agreement with the test results. However, the stiffness of the concrete degenerated rapidly due to the apparent development of plastic-damaged concrete, which made the falling section of the hysteresis curve of the numerical simulation different from that of the test. The proposed simplified modeling method can be further applied to the performance study of prefabricated shear walls with sleeve grouting defects and can provide a reference for structural performance evaluation, design optimization, and construction quality control to a certain extent.

A piecewise-linear backbone model for unbonded post-tensioned concrete masonry shear walls

Unbonded post-tensioned concrete masonry (UPCM) shear walls present an effective seismic force resisting system due to their ability to mitigate expected damage risks through their self-centering capabilities. A few design procedures were proposed to predict the in-plane flexural response of UPCM walls, albeit following only basic mechanics and/or extensive iterative methods. Such procedures, however, may not be capable of capturing the complex nonlinear relationships between different parameters that affect UPCM walls’ behavior or are rather tedious to be adopted for design practice. In addition, the restricted datasets used to validate these procedures may cast doubt on their accuracy and validity for new, unseen data, further hindering their adoption by practitioners and design standards. To address these issues, an experimentally-validated nonlinear numerical model was adopted in this study and subsequently employed to simulate 95 UPCM walls with a range of different design parameters to compensate for the lack of relevant diverse experimental data in the current literature. Guided by mechanics, and employing this database, an evolutionary algorithm—multigene genetic programming (MGGP), was adopted to uncover the relationships controlling the response of UPCM walls, and subsequently develop simplified closed-form wall behavior prediction expressions. Specifically, through integrating MGGP and basic mechanics, a piecewise-linear backbone model was developed to predict the load-displacement backbone for UPCM walls up to 20% strength degradation. Compared to existing predictive procedures, the prediction accuracy of the developed model and its closed-form nature are expected to facilitate better understanding of such wall behaviors and subsequently open the gate to further incorporate other experimental and numerical results to ultimately deploy UPCM in mainstream building designs in the near future.

Lateral behavior of wood frame shear wall using PVC wood-plastic composite (WPC) veneer panels

With the growing awareness of environmental protection and green ecology, there has been significant attention on the utilization of new energy-saving and environmentally friendly materials in building structures. This article proposes a novel structure for PVC wood-plastic composite wall panels. The structure comprises Polyvinyl Chloride (PVC) wood-plastic composite materials as the facing panel and SPF (Spruce-Pine-Fir) dimensional lumber as the wall framework, connected using self-tapping screws. In this study, two standard composite wall panel specimens were subjected to testing using both monotonic loading and low-cycle reciprocating loading methods. Finite element models of the composite wall panels were created using ANSYS Workbench software for analysis, investigating the lateral performance of PVC wood-plastic composite wall panels. The analysis results indicate that PVC wood-plastic composite wall panels exhibit favorable shear strength, elastic lateral stiffness, and lateral deformation as shear walls. The shear wall model can be accurately represented in finite element software, with minimal discrepancy between experimental and finite element analysis results. Consequently, the utilization of PVC wood-plastic composite wall panels as shear walls holds promise for future applications in the structural field.

A New Macro-Element for Predicting the Behavior of Masonry Structures under In-Plane Cyclic Loading

A new macro model for the finite element modeling of unreinforced masonry (URM) exhibiting in-plane nonlinear cyclic behavior is proposed. The ultimate objective is to predict the seismic response of multi-story URM buildings. The macro model enables the modeling of URM shear walls with a limited number of degrees of freedom (DOF) at low computation times. The macro model consists of a deformable elastic frame supported by diagonal struts with nonlinear behavior aiming to capture all dissipative phenomena occurring during seismic events. The nonlinear constitutive behavior of diagonal struts is inspired by models documented in the literature, ensuring a robust foundation for the proposed approach. This paper first provides a comprehensive review of the principal models currently available for URM analysis. It then articulates the rationale behind the development of this new numerical model, aiming to address the limitations encountered in existing methodologies and to offer a simple and fast tool for predicting the seismic behavior of URM buildings. Afterward, the new model is presented and tested with the simulations of two experimental campaigns performed on different URM walls. The comparison between experimental and numerical results shows that with a limited number of DOF and parameters, it is possible to obtain a prediction of the experimental results with satisfying accuracy.

Machine Learning Prediction Model for Boundary Transverse Reinforcement of Shear Walls

Due to their roles as efficient lateral force-resisting systems, reinforced concrete shear walls exert a tremendous degree of influence on the overall seismic performance of buildings. The ability to predict the boundary transverse reinforcement of shear walls is critical to the seismic design process, as well as in the overall evaluation and retrofitting of existing buildings. Contemporary empirical models attain low predictive accuracy, with an inability to capture nonlinearity between boundary transverse reinforcement and different influencing variables. This study proposes a boundary transverse reinforcement prediction model for shear walls with boundary elements based on the demand of ductility. Using the extreme gradient boosting machine learning algorithm and 501 samples, some 52 input variables are considered, and a subset with six features is selected, monitored, and analyzed using both internal methods (gain and cover) and external methods. The results (R2=0.884) display superior predictive capacity compared with existing models. Interpretation and error analysis are performed. Safety analysis is conducted to obtain references for use in practical engineering. Overall, this study presents a more accurate tool for use in seismic design and provides references for the evaluation and retrofitting of existing buildings. Our contributions hold significant implications for enhancing the safety and resilience of reinforced concrete structures.

Seismic performance of fabricated shear wall structures with design defects

The sleeve grouting connection stands as a customary method for interlinking precast shear walls within assembly construction. In the realm of on-site construction, achieving complete avoidance of sleeve grouting defects remains a challenge. In an endeavor to scrutinize the seismic performance and the subsequent progression of damage within shear wall structures riddled with sleeve grouting defects, a two-story shear wall model was formulated through the utilization of ABAQUS software. Employing numerical simulation of low cycle reciprocating loading, the study was conducted across three distinct operational contexts: absence of defects, localized defects, and comprehensive defects. The outcomes proffer insight into the exacerbated concrete damage triggered by defects present within shear wall structures. These defects contribute to premature yielding of reinforcement and a consequent amplification in the plastic length of the reinforcement, consequently impeding the harmonized deformation of reinforcement and concrete. The “pinch phenomenon” is particularly conspicuous within fully defective structures during the nascent loading stages. As cyclic loads mount, the hysteretic curves of both defective and defect-free structure tend to converge. While the skeleton curve of structures, whether grouting defects are present or not, demonstrates remarkable parity prior to reaching the pinnacle reaction force, the defective structure displays premature waning in reaction force. This, in turn, curtails the efficacy of early warning concerning structural deformation and jeopardizes safety. In light of the foregoing analysis, it is manifest that the presence of sleeve grouting defects significantly impacts the seismic performance and subsequent damage trajectory of shear wall structures. As a corollary, addressing and mitigating these defects during on-site construction emerge as imperative prerequisites for upholding the comprehensive safety and stability of the structure.

Numerical Modeling and Parametric Assessment of Log Shear Walls with Bonded Corners

ABSTRACT The paper investigates the stiffness and strength of log walls with standard and dovetail bonded corners under lateral loads. The finite element model is developed and validated with experimental work at small-scale and wall-scale levels. The validated wall-scale model was modified by conducting a detailed investigation on assessing the wall behaviour with varying crucial parameters, including coefficient of friction, vertical load, geometric irregularities, and the wall’s aspect ratio. The study suggested various techniques for improving the wall’s lateral load resistance capacities and initial stiffness, employing steel and wood pins.

Structural function analysis of shear walls in sustainable assembled buildings under finite element model

Abstract With the quick progress of industrialization and urbanization, the construction industry has become one of the largest energy-consuming industries. However, the current prefabricated shear wall focuses on the upgrade of seismic function, with less analysis of the energy efficiency of the overall structure. In this study, a sustainable prefabricated building shear wall that takes into account both energy conservation and stress is first proposed, and then the shear wall is modelled by finite element method (FEM) software. Meanwhile, the force functions of the shear wall model, including concrete strength, axial condensability rate, and aspect rate, and finally the seismic function are verified. The experimental outcomes demonstrate that the maximum difference between the FEM analysis outcomes and the test data is only 10.66%, and the overall difference in the outcomes is relatively small. The larger the aspect rate of the proposed sustainable assembled shear wall model, the better the ductility of the member, and the bigger the axial condensability rate and concrete strength, the lower the ductility of the member. In the seismic function analysis, the maximum layer displacement angles of this shear wall are all less than 1/120, which is in line with the national seismic code. This indicates its good seismic function and provides a methodological reference for the upgrade of the structural function of shear walls.

Seismic Performance of Reinforced Concrete Buildings with Different Lateral Load

Shear wall, steel bracing and combined system are the most commonly used lateral-load resisting technique for high-rise buildings. Shear walls have very high in-plane strength and stiffness, which can be used simultaneously for resisting large horizontal and gravity loads. The aim of this study is to examine how well reinforced concrete buildings withstand seismic activity using various systems for resisting lateral loads. In this study, a reinforced concrete building with 12 floors (G+12) and 5 X 5 bays is selected, and various lateral load resisting frame systems are applied in different positions. These are shear wall, bracings, shear wall-bracings combinations (Combined) at five different locations/patterns i.e., at outer corners (Type- I), center of outer sides (Type- II), middle corners (Type- III), center of middle sides (Type- IV), and inner core and middle sides (Type- V) respectively. A total of sixteen models are created for this study, with one being a bare frame and the other fifteen consisting of three types of lateral load resisting systems arranged in five different configurations each. With the assistance of ETABS all models are analyzed by Equivalent Static Analysis and Response Spectrum Analysis. The performance of building is evaluated on the basis of following parameters- maximum storey displacement, maximum storey drift and storey shear. At last the results are compared for different models. Among the three systems, the shear wall system exhibits the least displacement and the highest stiffness. Response of combined system is better than that of bracing system. Overall, the Type II shear wall model is more earthquake-resistant and structurally efficient than the other fifteen models. Key Words: Equivalent Static Analysis, Response Spectrum Analysis, Maximum storey displacement, Maximum storey drift, Storey shear

A Force-based Method for the Numerical Simulation of a Reinforced Concrete Shear Wall Building

Reinforced Concrete (RC) shear walls are structural elements that resist lateral loads. This research aims to present the numerical modeling of RC shear walls in order to evaluate the seismic performance of structures. Various types of numerical models of RC frame elements are implemented in nonlinear analysis packages. These numerical models are based on different theories and assumptions, something that poses a significant difficulty to practicing engineering and limits confidence in the analysis of the numerical results. In this study, inelastic force-based elements and distributed plasticity methods are used for the modeling of the inelastic behavior of these elements (infrmFB). The efficiency of the inelastic force-based element and distributed plasticity method is evaluated through the comparison with the experimental results of a shear wall structure subjected to seismic loadings. The accuracy of the numerical model is assessed in terms of top displacement, inter-story drift, base shear force, and the absolute maximum values of the overturning moment.

Torsional behavior of hybrid fiber reinforced shear walls an experimental point of view

AbstractThe shear wall system is one of the most commonly used lateral load‐resisting systems in reinforced concrete (RC) high‐rise buildings. The present work is designed to investigate the behavior of reinforced shear walls upon their hybrid fiber ratio, the horizontal reinforcement ratio, and for the reinforcement aspect ratio. For this purpose, nine‐shear walls were manufactured. The same longitudinal reinforcement ratio and the steel and carbon fibers were the main design concept. Withal, the self‐compacting concrete with fiber hybridization was the general perspective for the RC. All the shear wall models were inspected not only for torsion, but also for the energy dissipation capacity, crack propagation, etc. Torsional moment capacity increased, when the hybrid fiber ratio rose up from 0% to 1.0% and then 1.5%. However, this increase was larger in case of increasing the hybrid fiber ratio from 0% to 1.0%. Increasing the hybrid fiber ratio from 1.0% to 1.5% did not result in a performance increase as in the first case. Increasing the fiber ratio from 0% to 1% and from 1% to 1.5% increased the maximum torsional moment between 7.39% and 33.41%. Torsional moment and twist angle capacities increase with the increase in hybrid fiber and horizontal reinforcement ratio and the decrease in the aspect ratio in RC shear walls. Withal, the energy absorption capacity, ductility, and stiffness are also increased as the hybrid fiber ratio. Increasing the hybrid fiber ratio decreased the crack density in the plastic hinge region. Decreasing the aspect ratio from 1.5 to 1.25 increased the dissipation energy capacity between 68.75% and 100%. The addition of 1.0% fiber, a significant increase in the value of ~30% and 53% was achieved stiffness after the crack.

Experimental and numerical investigation on the seismic performance of RC squat shear walls with single post-opening reinforced by steel plates

The pseudo-static tests of one RC squat shear wall without opening and the other three RC squat shear walls with different arrangements (center, bottom, and top) of a single post-opening, reinforced by bonding steel plates, were carried out to simulate the defects caused by the post-opening at different locations and investigate the effect of post-opening location on the seismic performance of reinforced squat shear walls. The corresponding models of the tested specimens and also the other three models of the RC shear walls with the same opening and without any reinforcement were analyzed with Abaqus software. Results indicated that the shear wall without opening and the reinforced shear walls with a single post-opening show flexural shear failure. The relative difference between the bearing capacity of the three reinforced specimens and the reference specimen is not more than 6%. The average displacement ductility coefficients of reinforced shear walls with the central and bottom openings were reduced by 9.62%, while that of reinforced shear walls with the top opening was increased by 23.01%. FEA further reveals that the steel plate significantly reduces the uneven distribution of the reinforcement strain around the opening for shear walls with different post-opening locations.

A nonparametric seismic reliability analysis method based on Bayesian compressive sensing – Stochastic harmonic function method and probability density evolution method

In engineering practice, the evaluation of seismic reliability of high-rise reinforced concrete structure relies on the probabilistic modelling of material properties. However, the measured data of material parameters in engineering practice is usually inadequate to determine the probability model accurately, especially for the problems involving spatial variability. Traditional parametric reliability analysis methods can be biased for this kind of problem. Therefore, a nonparametric seismic reliability analysis method is proposed based on the Bayesian compressive sensing – stochastic harmonic function method and the probability density evolution method. In this method, the conditional random fields are generated and applied to represent material properties of concrete. As a result, the seismic reliability of a high-rise reinforced concrete shear wall model structure is analyzed using the probability density evolution method.

Experimental and Numerical Study of the Behavior of RC Shear Wall with Opening Using Concealed Stiffeners

A shear wall becomes weak when an opening is provided in it. It is important to provide some arrangement in the shear wall having an opening for recovering strength loss due to the opening. It may be recovered by providing some steel profiles around the opening or at weaker sections in the shear wall having an opening. At first, the identification of weaker sections in the shear wall having an opening is important and then, the wall can be made stronger as the shear wall without an opening by strengthening weaker sections. In the present study, the performance of a shear wall having an opening subjected to horizontal cyclic loading along the plane of the shear wall in the presence of concealed stiffeners is investigated. The reduced models of shear walls with openings were tested under axial and lateral load conditions. Load-carrying capacity, deformation behavior and strain behavior of shear walls were studied with experiments and the validation of the results was made with general-purpose finite element software ANSYS. Significant improvements were observed in strength, deformation and strain behavior of a shear wall having a central opening using concealed reinforced concrete (RC) stiffeners and steel tube stiffeners. KEYWORDS: Shear wall, Strength, Stiffness, Strain, Openings, Stiffeners.

Testing, modelling and analysis of full-scale cold-formed steel center-sheathed shear walls in fire

Cold-formed steel center-sheathed shear wall (CFSCSSW) is an innovative shear wall applied to multi-story cold-formed steel buildings. In this study, six tests were carried out on CFSCSSWs, including one room temperature test to obtain load-bearing capacity and five fire tests to investigate the influence of the vertical load ratio, lateral load ratio, interior stud and aspect ratio on the fire behavior of the CFSCSSWs. Subsequently, finite element models were developed to investigate the influence of various combinations of vertical and lateral loads and the sheathing thickness on the fire behavior of the wall. The research results showed that the temperature distribution along the thickness of the wall section is quite non-uniform and the maximum difference reaches 65% from the hot flange to the cold flange. The effect of the vertical load ratio on the fire resistance of the wall is greater than that of the lateral load ratio. The interior stud plays a positive role in improving the fire resistance of the wall. The aspect ratio has little influence on the fire resistance of the wall. The failure model of the wall mainly depends on vertical or lateral loads as well as the aspect ratio. With the increase in the vertical load ratio, the failure location of the wall moves down. Based on the parametric studies, a sheathing thickness of 0.8 mm was recommended for CFSCSSWs.