Infill Plate Research Articles

Optimizing steel plate shear wall performance: influence of infill plate thickness and connection length to vertical boundary elements

The Steel Plate Shear Wall (SPSW) is widely used as a lateral force resisting system in areas prone to high seismic activity. This is because of its exceptional ductility and ability to dissipate energy. Previous studies have indicated that disconnecting the infill plate from the Vertical Boundary Element (VBE) can decrease the demands on the column. The observed outcomes lead to a decline in both the energy dissipation capability and the lateral load-bearing capacity. The primary goal of this investigation is to mitigate stress on the column while concurrently reducing both the energy dissipation and lateral force capacities. To accomplish this, a partial connection will be established between the infill plate and the Vertical Boundary Element. Thus, the overarching objective of this research is to identify the optimal connection length that minimizes the demands on the column while simultaneously curtailing the reduction in energy dissipation and lateral force capacities. Using Abaqus software, twenty models with different infill plate thicknesses and lengths of connection between the infill plate and Vertical Boundary Element were analysed. To determine the optimal length of connection between the infill plate and Vertical Boundary Element, the energy dissipation capacity, lateral load capacity, and column stresses were evaluated and compared. The maximum dissipation of energy occurs at a connection length of 75% between the infill plate and Vertical Boundary Element and an infill plate thickness of 12 mm. In contrast, the greatest lateral load capacity is achieved at connection lengths of 50% between a 25 mm infill plate thickness and a Vertical Boundary Element weight of 25%. The column stress reaches its minimum value when the infill plate measures 20 and 25 mm, and it reaches its maximum value when the infill plate measures 6 mm and 12 mm. By increasing the thickness of the infill plate and minimizing its connection to the Vertical Boundary Elements, the column stress in Vertical Boundary Elements can be decreased, while simultaneously enhancing lateral load capacity and maintaining an adequate level of energy dissipation.

Cyclic behavior of improved low-yield point steel plate shear walls with T-shaped stiffeners

Based on the demand for high-performance lateral force-resistance systems for high-rise buildings, a new stiffened low-yield point (LY) steel plate shear wall (SPSW) structure is proposed. The infill plate is made of LY steel, and the stiffeners adopt a T-shaped section with greater flexural stiffness. Quasi-static tests are conducted on one unstiffened low-yield point steel plate shear wall (L-SPSW) and two stiffened L-SPSWs (using T-shaped cross and diagonal stiffeners). The cyclic behaviors of the L-SPSWs are compared through failure mode, damage development, hysteresis performance, and deformation performance. Numerical models are established and validated through experimental results. Finally, the performance of L-SPSWs with T-shaped and plate-type stiffeners is analyzed. The results show that the T-shaped cross stiffeners have the greatest enhancement in energy dissipation capacity (EDC) and stiffness, as well as the strongest suppression of the out-of-plane deformation (OPD) of the whole plate. T-shaped diagonal stiffeners have the greatest impact on enhancing the bearing capacity. It is suggested to strengthen the weld quality or select a steel material with LY for the diagonal stiffeners to ensure ductility. The use of T-shaped stiffeners can maximally improve the restraining effect on the OPD of the infill plate by 38.1 % compared with plate-type stiffeners.

Topology optimization of the flat steel shear wall based on the volume constraint and strain energy assumptions under the seismic loading conditions

In structural engineering systems, shear walls are two-dimensional vertical elements designed to endure lateral forces acting in-plane, most frequently seismic and wind loads. Shear walls come in a variety of materials and are typically found in high-rise structures. Because steel shear walls are lighter, more ductile, and stronger than other concrete shear walls, they are advised for usage in steel constructions. It is important to remember that the steel shear wall has an infill plate, which can be produced in a variety of forms. The critical zones in flat steel shear walls are the joints and corners where the infill plate and frame meet. The flat infill plate can be modified to improve the strength and weight performance of the steel shear walls. One of these procedures is Topology Optimization (TO) and this method can reduce the weight and also, increase the strength against the cyclic loading sequences. In the current research paper, the TO of the infill steel plate was considered based on the two methods of volume constraint and maximization of strain energy. Four different volumes (i.e., 60%, 70%, 80%, and 90%) were assumed for the mentioned element in the steel shear wall. The obtained results revealed that the topology configuration of CCSSW with 90% volume constraint presented the highest seismic loading performance. The cumulated energy for this type of SSW was around 700 kJ while it was around 600 kJ for other topology optimization configurations.

Methodical Investigations on Seismic Retrofitting of Steel Plate Shear Wall Systems

An efficient retrofitting technique is expected to improve the seismic performance of a lateral force-resisting system without increasing the seismic demand on the structure, which can unfavorably lead to irreparable damages during a seismic event. On this basis, the present study aims to introduce an optimal strategy for seismic retrofitting of steel plate shear wall (SPSW) systems using low yield point (LYP) steel material and to demonstrate its effectiveness through systematic investigations. To this end, detailed nonlinear static, cyclic, and dynamic analyses, as well as fragility analyses, have been performed on single- and multi-story, code-designed as well as retrofitted SPSWs. The aim is to identify the most efficient retrofitting approach and to demonstrate its effectiveness in enhancing the seismic performance and lowering the seismic vulnerability of the system. It is shown that replacing the original, conventional steel infill plate in an SPSW system with an LYP steel plate having twice the original thickness can improve not only the buckling capacity and serviceability, but also the structural performance and seismic response of the system, without increasing the demand on the structure and creating overstrength concerns. Fragility analysis also shows that the vulnerability, as well as probability, of damage to system can be considerably lowered as a result of the implementation of such a retrofitting strategy.

Predicting the shear capacity of composite steel plate shear wall with the application of RSM

This research aims to predict the maximum shear capacity of Composite Steel Plate Shear Walls (CSPSWs) through nonlinear Finite Element (NLFE) analyses and Response Surface Method (RSM). The variables are concrete thickness and compressive strength, steel infill plate thickness, and yield stress. A parametric study was performed on CSPSW comprising a concrete layer on one side of the infill plate and the corresponding models having the concrete layer between the two plates. The results show that RSM is a reliable practice for precisely predicting the maximum shear capacity of the studied models. Furthermore, comparing the RSM results with those acquired by Linear Regression (LR) indicated that RSM is more accurate than LR. Moreover, in the models with the internal concrete layer, the concrete contributed more to the shear capacity of the specimens, and this difference expands with an increase in the thickness of the concrete layer.

Shape memory alloys effects on the multi-story structures under extreme loading conditions

The use of intelligent materials with particular behavioral traits has grown significantly in recent years. The most common materials that may revert to their original shape after deformation due to stress or heat change are shape memory alloys (SMAs). Shape memory alloy (SMA) differs from conventional materials due to its shape memory property and hyperplastic nature. This research aims to explore the use of SMAs as a reinforcement to improve the performance of multi-story steel plate shear walls (SPSW) under explosive loading. The finite element (FE) software "ABAQUS" is utilized to simulate the models, and the results of the numerical modeling are validated against experimental research from the literature. The study investigates the impact of different parameters related to the explosion on the behavior of the reinforced multi story SPSW, including the amount of explosive material and the location of the explosion. The findings reveal that the minimum amount of explosive material required to cause rupture in a four-story SPSW reinforced by SMA, positioned at a distance of 1 m from the structure, is equivalent to 40 kg of TNT. Additionally, the minimum distance required for element rupture in the four-story SPSW, reinforced by SMA strips, is found to be 0.5 m. As the explosion height increases, the amount of out-of-plane base shear decreases. Furthermore, an interesting observation is that as the explosion height increases, the displacement of the infill plate also increases, leading to beam failure and, ultimately, infill plate failure. Niti SMA exhibited superior blast resistance compared to Iron-based SMA, showcasing its potential for enhancing structural resilience.

Cyclic behavior of sandwich steel plate shear wall with embedded corrugated plate

The sandwich structure has superior properties. To explore the application of sandwich structures in steel plate shear walls, this study presents a sandwich steel plate shear wall with embedded corrugated plate (ECSSW). The proposed wall is composed of two flat plates and a corrugated plate embedded between them. The flat and corrugated plates are joined by connectors. To study the cyclic behavior of the ECSSW, a quasi-static test and a numerical simulation of two specimens were conducted. In addition, a parametric assessment was conducted on the ECSSW with different connector horizontal spacings and strengths. The results showed that the ECSSW provides satisfactory seismic performance, does not produce significant noise, and can effectively delay the occurrence and development of infill plate buckling. With a small-wavelength embedded corrugated plate, the ECSSW can increase the yield load and yield displacement. The ECSSW with a large-wavelength embedded corrugated plate can reduce stiffness degradation and increase ductility and energy dissipation. When the strength of the connector is low, its horizontal spacing has minimal effect on the cyclic behavior of the ECSSW. The strength of the connector significantly affects the out-of-plane deformation of the ECSSW.

Seismic behavior of a novel slotted steel plate shear wall under monotonic, cyclic, and time history analysis

Steel plate shear walls (SPSWs) are lateral load-resistant systems used as energy dissipation members in new or existing structures due to their stable hysteretic behavior. However, structures equipped with conventional SPSWs may have a higher initial stiffness, which causes them to be subjected to too much force during moderate earthquakes. In the present study, a novel slotted SPSW is developed to minimize the lateral forces of traditional SPSWs. The slotted SPSW consists of horizontal boundary elements (HBEs), vertical boundary elements (VBEs), and two layers of incline-slotted infill plates (ISIPs) connected by high-strength steel bolts. The proposed system's seismic behavior and damaged mode were compared with those of conventional SPSW using monotonic and cyclic analysis. The research results show that the slotted SPSW exhibits stable hysteretic behavior with a significant energy dissipation capacity. Furthermore, the slotted SPSW was applied to a three-story frame structure. Nonlinear time history analysis was conducted under far-field and near-field ground motion records to determine how a slotted SPSW system affects structure response. According to numerical results, the base force of the structure equipped with a slotted SPSW system was minimized to 37.0% and 49.6% under near-field and far-field earthquakes, respectively.

Analysis and design of a novel segmented energy absorbing steel plate shear wall system

A steel plate shear wall (SPSW) system capable of providing strength and stiffness under normal load conditions and dissipating energy under extreme load conditions is proposed. The infill plate of this proposed Segmented Energy Absorbing SPSW (SEA-SPSW) system consists of two trapezoidal plate segments. For each plate segment, one edge is connected to the beam while the opposite edge is joined together by steel strips. The steel strips are held together using high strength bolts with long-slotted holes. Under normal load conditions, the SEA-SPSW behaves like a conventional SPSW. However, under extreme load conditions, the plate segments will slide between the steel strips and dissipate energy through friction. Because the proposed system does not rely on yielding or buckling to dissipate energy, it can be reset and reused after a severe load event. The behavior of this SEA-SPSW is studied using finite element and compared to an all steel conventional SPSW system. It is found that the proposed system not only helps reduce inter-story displacement, it also offers a desirable equivalent viscous damping ratio as well as a rather favorable energy dissipation to mass ratio.

Experimental and Numerical Study of Beam-Only-Connected Corrugated Steel Plate Shear Walls

ABSTRACT The cyclic performance of beam-only-connected Corrugated Steel Plate Shear Walls (CSPSWs) is studied experimentally and numerically. Two one-story single-bay specimens with single and double corrugated infill plates were built and tested under lateral cyclic load. The results demonstrated that CSPSWs could have a robust hysteresis curve with viable cyclic performance if designed properly. Finite Element (FE) models were developed and verified against test specimens. A parametric study was conducted using FE models to evaluate the effects of variations in the thickness, aspect ratio, and sub-panel width of the infill plate of beam-only-connected CSPSWs on their cyclic performance.

Improving the behavior of semi‐supported steel plate shear walls using diagonal stiffeners

AbstractAlthough Steel Plate Shear Walls (SPSWs) have revealed worthy performance in past studies, the need for huge columns surrounding the infill plate is accounted as a considerable shortcoming. This problem is created due to transferring the infill plate stress to the columns by post‐bucking. Despite using the semi‐supported SPSW, the problem is solved, however, the stiffness and ultimate strength of the SPSW are reduced. This reduction is due to the formation of incomplete tension field action. Therefore, in this paper, stiffening the semi‐supported SPSW using diagonal stiffeners is proposed and investigated numerically and parametrically. To do so, the effect of the stiffener properties, the thickness of the stiffener (ts), the width of the stiffener (hs), and the hs/ts ratio on the behavior of the system were evaluated. These stiffeners not only improve the behavior of the infill plate but also contribute to load bearing. Results indicated that by using the stiffeners, the ultimate strength, elastic stiffness, and energy dissipation capacity of the semi‐supported SPSW are improved, and with a lower hs/ts ratio, a better performance of the system is obtained.

A comprehensive analysis of guided-wave propagation in 3D-printed PLA plates with different infill densities – Experimental study

Thanks to its many advantages, additive manufacturing (AM) is witnessing a gigantic shift from small applications to the production of complex industrial components, including safety–criticalapplications like aerospace and civil construction. This arises the need to develop accurate and robust technologies for evaluating and monitoring the structural integrity of AM components. The objective of this study is to comprehend how ultrasonic guided waves (GWs) propagate in 3D-printed poly(lactic acid) (PLA) plates of different infill densities. The experimental investigation involves five intact PLA plates printed with infill densities ranging from 20 to 100% at a step of 20%. A scanning laser Doppler vibrometer was used to visualize GW propagation by performing full-wavefield area-scans. Spatial-time, frequency-wavenumber, and wavenumber-wavenumber analyses were performed to scrutinize the availableGW modes and their slowness profiles within the anisotropic structure. In addition, the tuning of the fundamental Lamb-wave (LW) modes at different excitation frequencies was examined, and the amplitude attenuation of the generally most pronounced mode (A0 mode) was investigated for different infill densities at an excitation of 50 kHz. A reference methodology is presented to experimentallyidentify more than five propagating modes in the frequency-wavenumber domain then obtain their phase-velocity dispersion curves. Significant variations are observed in the dispersion characteristics when lowering the infill density leading to the appearance of more modes at lower cutoff frequencies and drops in both the group and phase velocities in most of the cases. A complex behavior of the guided waves was observed in the dispersion curves of the 20%-infill plate, with possible mode interruptions/disturbance at an excitation frequency beyond 70 kHz. The appearance of shear-horizontal modes is noticed/strengthened at oblique propagation directions which may be attributed to mode conversion of the LW modes after obliquely interacting with the internal structure of the plates. Though high wave attenuation is a characteristic of the used polymer material, this attenuation is further increased at lower infill densities. The tuning behavior of the fundamental LW modes is also shown to be significantly affected by the infill density. The presented results can serve as reference propagation and dispersion characteristics for researchers working on similar materials and geometries. Such knowledge and understanding can be particularly useful for GW-based structural healthy monitoring of AM structures.

Seismic performance assessment of steel plate shear walls equipped with passive dampers

The main objective of the current study is to improve the structural resilience and damage control of steel plate shear walls (SPSWs) equipped with a unique passive visco-plastic damper. The proposed damper is made of a high-damping rubber layer with self-centering characteristics and ductile steel bolts. The seismic response of the novel SPSW system equipped with the aforementioned visco-plastic damper is evaluated using a three-dimensional nonlinear finite element analysis validated with experimental data. Furthermore, a parametric study is conducted to see the effect of different parameters such as the bolt diameter-to-height ratio, rubber thickness, number of bolts, number of dampers, location of the damper connection, and bolt material on the behavior of SPSW equipped with visco-plastic dampers under cyclic loading. Results showed that the suggested damper could concentrate most of the damages merely in itself and preserve the primary structural components in the undamaged elastic range, which acted as a structural fuse. The results indicated that to obtain the research objective, the bolt diameter-to-height ratio needs to be 0.2 or less, which in this case, more than 85% of the total input energy is absorbed by merely the damper and steel boundary columns and beam remained elastic and undamaged, while the infill plate had a relatively low energy absorption rate of roughly 10%. On the contrary, the infill plate of the conventional SPSW absorbed the highest energy, accounting for more than 75% of the total input energy. The beam also had a relatively high energy absorption rate of around 24%. In addition, the self-centering behavior of the proposed system could reduce nearly 36% of the residual lateral displacement compared with the conventional SPSW.

Theoretical and experimental investigations of steel plate shear walls with diamond openings

Steel plate shear walls (SPSWs), used in many high-rise buildings, have been the focus of considerable research. In existing designs, stress concentrations occur at the two ends of the rectangular belt of a slit shear wall. In contrast, the middle region is virtually unable to enter into the plastic state. Consequently, the strength and ductility of these members are not fully utilized. To resolve this, an SPSW with diamond openings (SPSW-DO) is proposed. In the proposed design the seismic energy is dissipated through the flexure and shear deformations of butterfly links on the wall; hence, the energy dissipation capacity of the SPSW-DO is fully utilized. In this study, the theoretical formulas for predicting the strength and elastic stiffness of the SPSW-DO are derived. Each butterfly link has three potential failure modes depending on the opening parameters: bending, bending–shear, and shear. A design procedure to determine the parameters of the opening is suggested according to the shear requirement for the intermediate section of butterfly links. Based on the experimental results of two specimens with different height-to-width ratios subjected to cyclic loading, the SPSW-DO is found to have reliable seismic performance. Finite element models are also developed to reproduce the experimental behavior, and the structural characteristics of the wall and the potential locations of fractures on the infill plate are predicted. Theoretical formulas for the elastic stiffness and strength of the system are also verified through comparison with the experimental results.

Investigation of the Behavior of Steel Plate Shear Walls Considering Double Corrugated Low-Yield-Point Steel Infill Plate

During the last three decades, interest in the application of steel shear walls has increased worldwide. Steel shear walls are used as stiffened and unstiffened walls. One of the main shortcomings of the steel plate shear wall (SPSW) is the infill plate buckling mainly under lateral wind and seismic loads. One of the useful solutions to prevent lateral buckling is the use of walls with corrugated plates. In this research, the behavior of a steel shear wall consisting of two corrugated plates was investigated in the two material cases of the conventional ASTM A36 steel and the low-yield-point (LYP) steel. The use of steel with low yield strength improves the seismic performance of the steel shear wall system. In this study, the effect of the corrugation angle and aspect ratio of the plate were investigated. The results showed that the effect of corrugation angle on the structural parameters of walls with LYP steel is greater than that of walls with A36 steel. By increasing the corrugation angle from 30° to 60°, the elastic stiffness of A36 and LYP walls decreased about 24 and 36%, respectively, and the response modification factor (Ru) of A36 and LYP walls decreased by about 24 and 56%. The corrugation angle has a lower effect on the ultimate strength and energy absorption. Investigating the effect of aspect ratio showed that increasing the aspect ratio improves the seismic performance of the wall.

Seismic behavior evaluation of steel infill plate composite shear wall systems following FEMA P695 methodology

Seismic behavior evaluation of steel infill plate composite shear wall systems following FEMA P695 methodology

Numerical Analysis of Infill Plate Performance on Steel Plate Shear Wall (SPSW)

Steel Plate Shear Wall (SPSW) is one of the systems that can be used to minimize the effect of earthquakes on buildings. The main energy-absorbing element of the steel plate shear wall system is on the thin steel plate that are located on the center of the steel frame. This thin steel plate is called infill plates. This infill plate will later experience buckling and form a series of tension field action. This paper will prove that the infill plates in the steel plate shear wall system provides significant strength contribution in resisting lateral loads.The analysis was carried out by comparing the strength provided by steel plate shear wall system and simple beam-column steel frame system (without infill plate) with some aspect ratio variation (width per height). The material used for the infill plates was low yield strength (LYS) steel plate of 1.30 mm thick, while the column (vertical boundary element) used WF 400.200.8.12, and the beam (horizontal boundary element) used WF 350.175.7.11. The loading used a monotonic pushover loading of 2% drift (68.8 mm) for each specimen.The analysis result proved that the steel plate shear wall system (frame with infill plates) had significant strength advantage compared to the plateless frame system. The aspect ratio (L/h) on infill plates were also affects the strength of the entire system, where the greater the aspect ratio, the greater the strength. The strength value of the SPSW specimen at 2% drift loading on aspect ratio L/h = 1.00, 1.50, 2.00, 2.50 respectively was 614.95 kN, 634.88 kN, 646.69 kN, and 688.03 kN. Meanwhile, the strength increment percentage between steel plate shear wall systems compared to plateless frame systems in each aspect ratio was 21.67%, 32.39%, 42.48%, and 54.20%.

Investigation of lattice infill parameters for additively manufactured bone fracture plates to reduce stress shielding

BackgroundStress shielding is a detrimental phenomenon caused by the stiffness mismatch between metallic bone plates and bone tissue, which can hamper fracture healing. Additively manufactured plates can decrease plate stiffness and alleviate the stress shielding effect. MethodsRectilinear lattice plates with varying cell sizes, wall thicknesses, and orientations are computationally generated. Finite element analysis is used to calculate the four-point bending stiffness and strength of the plates. The mechanical behaviors of three different lattice plates are also simulated under a simple diaphyseal fracture fixation scenario. ResultsThe study shows that with different combinations of lattice infill parameters, plates with up to 68% decrease in stiffness compared to the 100% infill plate can be created. Moreover, in the fixation simulations, the least stiff lattice plate displays 53% more average stress distribution at the healing callus region compared to the 100% infill plate. ConclusionsUsing computational techniques, it has been demonstrated that additively manufactured stiffness-reduced bone plates can successfully address stress shielding with the strategic modulation of lattice infill parameters. Lattice plates with design versatility have the potential for use in various fracture fixation scenarios.

Parametric study on the partially interconnected steel plate shear walls with stiffeners

Steel plate shear walls are a popular and effective lateral load-resisting system used in high-rise buildings. However, limited interconnection between the infill plate and boundary elements is recommended to avoid direct demands on the boundary elements and brittle modes of behavior. But previous studies have shown that the absence of interconnection between infill plates and columns in steel plate shear walls with beam-connected systems can reduce the system’s performance significantly. This study proposes procedures to improve the performance of steel plate shear walls with limited infill plate interconnections. Sixty-two parametric computational models were investigated with and without boundary infill plate stiffeners and different infill plate widths to find efficient procedures for eliminating the lack of interconnections. Results show that utilizing boundary stiffeners can increase ultimate strength, energy dissipation, and stiffness by 15%, 20%, and 24% on average. The width of the infill plate and boundary stiffeners are identified as key factors in the system’s performance. Reducing the infill plate width without using stiffeners exacerbates the performance of the lateral resisting system, resulting in a reduction of ultimate strength, energy absorption, and stiffness up to 17%, 24%, and 56%, respectively. Analytical equations are proposed and verified to predict the behavior of steel plate shear walls with partial infill plate interconnections with or without boundary stiffeners. Overall, the study provides procedures and recommendations to improve the performance of steel plate shear walls with limited infill plate interconnections.

Investigation of the effect of trapezoidal infill plate angle on the behavior of the corrugated steel shear walls – An experimental and numerical study

AbstractStudies on corrugated steel shear walls (CSSWs) generally indicate a noticeable increase in energy absorption, as well as an increasing shear buckling capacity of corrugated plates more than the flat plates. In this article, the effect of changing the angle of the trapezoidal panel on the behavior of CSSWs has extensively been investigated. Three specimens of CSSW with one story and single bay in half‐scale are tested under cyclic load. Gravity loads are not applied at the top of the walls; however, the horizontal load has been applied at the top of each specimen. The loading sequence has been implemented through “displacement control” with increasing and decreasing amplitudes. The observations of the experiment do indicate that stress concentration has been increased in the corner of subpanels, by increasing the corrugation angle. Also, the stiffness and energy dissipation are getting decreased, by growing the corrugation angle. Investigating the numerical models has been showing that in CSSW, seismic factors are affected by corrugation angle; however, varying parameters against changing angles do not show any reasonable relationship. The obtained results of investigating the effect of surrounding frame stiffness variation on the behavior of walls have also been indicating that increasing frame stiffness shall not be leading to improving all seismic parameters.