Infill Plate Research Articles

Seismic collapse assessment of stiffened steel plate shear walls using FEMA P695 methodology

Unlike unstiffened steel plate shear walls (SPSWs), very little research has been conducted to assess the seismic performance of stiffened SPSWs. This paper presents a new component strength deterioration model for stiffened infill plate to evaluate the seismic performance of stiffened SPSWs using FEMA P695 procedure. The newly developed component strength deterioration model is first validated against the available experimental results. A total of three multi-storey (7-, 10-, and 13-storey) stiffened SPSWs with panel aspect ratio of 1.39 are then analysed using the proposed component strength deterioration model. Static pushover and incremental dynamic analyses using a suite of 44 ground motions compatible to Western Canada are conducted for all archetypes. Adjusted collapse margin ratios obtained for stiffened SPSWs designed with similar response parameters of those for unstiffened SPSWs are compared with allowable limits given in FEMA P695. The results indicate that currently recommended seismic response modification factor, ductility related force modification factor and overstrength related force modification factor, for unstiffened SPSW can be used for design of stiffened SPSW. In addition, seismic response parameters such as variation of maximum interstorey drift and shear demand in different components of stiffened SPSW, boundary columns and infill plates, are estimated in all stories for all designed archetypes during incremental dynamic analysis. Furthermore, seismic response sensitivity of stiffened SPSWs to the variation of post-yielding parameters (i.e., ductility capacity and post-cap stiffness ratio) in infill plate is investigated. Sensitivity analysis shows that the capacity of stiffened SPSW is more sensitive to ductility capacity changes, while the variation of post-cap stiffness has a lesser effect on overall performance of the system.

Improving behavior of semi-supported steel plate shear walls

In spite of the good performance of the steel plate shear wall (SPSW) in recent earthquakes and experimental studies, the need for huge columns to surround the infill plate is a major shortcoming of the system. This shortcoming can be resolved by using semi-supported SPSW. The semi-supported SPSW has secondary columns that prevent the transfer of stress from the infill plate to the main columns. In spite of extensive experimental and numerical investigations on SPSWs, there are many ambiguities regarding the behavior of the semi-supported SPSW. Although stress in the columns is reduced, incomplete diagonal tension field action is formed in the infill plate that creates new problems. In this paper, a new type of semi-supported SPSW is presented in which the steel plate and the secondary columns are angled. The creation of the angle of the plate and the secondary column makes it possible to use the full capacity of the steel plate as well as the capacity of the secondary columns. Numerical results showed that the wall with a 60° angle has a favorable performance relative to the semi-supported wall. Moreover, with the 60° angle, stiffness, strength and energy absorption is increased. The angle of the secondary columns has little effect on the non-elastic stiffness. Nevertheless, using a wall with an angle of more than 90° can neutralize the wall’s behavior relative to conventional walls. Therefore, the wall with a 60° angle as an optimal angle is recommended.

Seismic performance of discontinuous cover-plate connection for prefabricated steel plate shear wall

In this study, a discontinuous cover plate connection (DCPC) was proposed for a prefabricated steel plate shear wall with a beam-only-connected infill plate. This design is suitable for prefabricated high-rise steel structures and assumes that bolt slippage does not precede the yielding of the steel plate tension field. Three 1/3-scale specimens were designed, and the hysteretic behaviour, skeleton curves, energy dissipation capacity, ductility, and failure modes were investigated using quasi-static tests and finite element analyses. Then, the hysteretic behaviour, ductility, and energy dissipation capacity of the prefabricated steel plate shear wall were compared to those of a traditional welded steel plate shear wall through finite element analyses. The results showed that the prefabricated steel plate shear wall with a DCPC had good hysteretic behaviour, energy dissipation capacity, and ductility. Further, the bolt pre-tightening force in the connection was directly proportional to the thickness of the infill plate. The ultimate lateral bearing capacity of the prefabricated steel plate shear wall was slightly less than that of the welded steel plate shear wall. In addition, the prefabricated steel plate shear wall can be assembled rapidly and simply on-site, and it provides a good post-earthquake repairable function.

Investigation of Failure Mechanism of Thin Steel Plate Shear Wall in RC Frame

In this paper, the behavior of steel plate shear wall (SPSW) in the reinforced concrete frame (RCF) has been studied numerically. Three different connections have been proposed to connect SPSW to RCF. In the first connection, fish plates, while in the second one, combination of fish plates and studs transfer forces between SPSW and RCF. In the third connection, there is no direct connection between the infill plate and RCF, and additional steel frame has been used for connecting of the infill plate. The results demonstrate that, load carrying capacity increases in all the specimens comparing the reference RCF. Investigating the formation sequence of plastic hinges in different specimens demonstrates that there is different sequence in the specimens with different connections.

Characterizing the Cyclic Behavior of Stiffened SPSWs

To enhance the behavior of steel plate shear walls, stiffeners are attached on the infill plate. The various researches on the stiffened Steel Plate Shear Walls (SPSWs) with Low Yield Point (LYP) infill steel plate have approved excellent capacity of this system. In those studies, the researcher focused on the specific type on stiffeners and in some cases, different results was reported. To cover different aspects, to provide comprehensive necessary data for structure designers and, to study the post-buckling and performance factors, this research is conducted. Using the validated Finite Element (FE) models with experimental test results, an analytical study of a single story SPSWs conducted to determine the influence of the selected parameters on the strength, stiffness, energy absorption and seismic performance factors. The variant parameters include the stiffeners pattern, stiffeners thickness, one-side or double-sides stiffeners and the slenderness of the stiffened infill plates. The results showed that cross-stiffened pattern is preferable in the one-side stiffening method while, diagonal pattern in double-side shape. Finally, the value of seismic performance factors is proposed for stiffened SPSWs.

Experimental investigation of strengthening reinforced concrete moment resisting frames using partially attached steel infill plate

Numerous methods such as adding different eccentric and concentric braces, steel or concrete shear walls, etc. are used to strengthen reinforced concrete (RC) frames. If the seismic characteristics of the hybrid seismic resistant system are not known, choosing the suitable system for strengthening would be difficult. In this paper, the behavior of a moment resisting reinforced concrete frame strengthened with partially attached steel infill plate subjected to cyclic lateral loads has been investigated. The assessment has been carried out through an experimental approach with conventional and perforated steel infill plates. Five moment resisting reinforced concrete frames with identical dimensions, steel content, and concrete strength were built with the scale of 1:3. Among the four samples, two incorporated perforated, partially attached infill plates and the other two were strengthened with conventional partially attached steel infill plates. Finally, the cracking pattern, effective stiffness, strength reduction factors, ductilities, ultimate strengths, and energy absorption capacities of all the samples were calculated and compared. The results show that using partially attached steel infill plate causes the cracking pattern of the strengthened frame to be almost similar to that of the initial frame. In addition, the perforated steel infill plate not only increases the stiffness and lateral strength of the frame, it also increases the strength reduction factor by 35%.

Nonlinear seismic performance of code designed perforated steel plate shear walls

Nonlinear seismic performances of code designed Perforated Steel Plate Shear Walls (P-SPSW) were studied. Three multi-storey (4-, 8-, and 12-storey) P-SPSWs were designed according to Canadian seismic provisions and their performance was evaluated using time history analysis for ground motions compatible with Vancouver response spectrum. The selected code designed P-SPSWs exhibited excellent seismic performance with high ductility and strength. The current code equation was found to provide a good estimation of the shear strength of the perforated infill plate, especially when the infill plate is yielded. The applicability of the strip model, originally proposed for solid infill plate, was also evaluated for P-SPSW and two different strip models were studied. It was observed that the strip model with strip widths equal to center to center diagonal distance between each perforation line could reasonably predict the inelastic behavior of unstiffened P-SPSWs. The strip model slightly underestimated the initial stiffness; however, the ultimate strength was predicted well. Furthermore, applicability of simple shear-flexure beam model for determination of fundamental periods of P-SPSWs was studied.

Experimental Performance Evaluation of Multi-Storey Steel Plate Shear Walls Designed by Different Methods

In accordance with two different design methods including the technical specification for steel structures of tall buildings and the shear-bearing capacity method for infilled steel wall plates, two types of steel plate shear wall with unstiffened panels have been designed and constructed. All shear wall specimens are exposed to ultimate static monotonic and low horizontal cyclic loading conditions to determine their structural behaviors under an idealized severe earthquake event. The seismic performances of these two types of specimens are identified by the overall roof displacement angle, lateral stiffness, ductility, different distribution of horizontal force and overturning moment, and inclined angle of diagonal tension field. These two types of steel plate shear wall exhibit excellent seismic performance. However, the specimens with thin infill plate thickness of 1.1 mm perform better than the thicker specimens with plate thickness of 3.75 mm. In terms of serviceability performance, the experimental results exhibit that the thicker specimens designed by the technical specification tend to be more conservative. Their over-strength factor, strength assurance coefficient and drift angle are 4.98, 6.3 and 1/1335, respectively. However, the thinner specimens designed by the shear capacity method for shear panel yield the serviceability performance factors of 2.22, 2.71 and 1/407, respectively. It is important to note that design practice generally adopts the over-strength factor between 2 and 3, and the strength assurance coefficient is often designed for 3 and the maximum inter-story drift limit given by the design specification is 1/300. On this ground, it is apparent that the shear-bearing capacity method enables relatively more economical compared to the technical specification for steel structures.

Behaviour of connections for hybrid FRP/steel shear walls

The design of more efficient and lightweight steel shear walls (SSW) has led to research in incorporation of fibre reinforced polymer (FRP) composite in the infill plate of shear wall systems. As a result, understanding the behaviour of the connections between the hybrid steel/FRP infill plate and the fish plate of the surrounding frame elements has become necessary. In this paper, energy absorption and load carrying capacity of FRP-to-steel connections has been investigated to develop a more efficient hybrid steel/FRP shear wall system. Monotonic displacement controlled loading of bolted connections, representing the connections in steel and hybrid shear walls, were conducted to complete failure. The specimens had dimensions of 125 mm × 70 mm with varying factors some of which were using two and three bolts connections, applying additional GFRP strips, using adhesive between the steel plate and the internal layer of GFRP as well as applying adhesive between the clamping plate and the FRP around the bolted area. A detailed comparison between the specimens in aspects of energy absorption, load capacity and modes of failure is provided.

Seismic Behavior Investigation of the Corrugated Steel Shear Walls Considering Variations of Corrugation Geometrical Characteristics

The corrugated steel plate shear walls have recently been proposed to address the seismic issues associated with simple steel plate shear walls; however, stiffness, strength, and ductility of the corrugated shear walls are significantly affected by varying the corrugation geometry under seismic loading. The present study investigates steel shear walls’ models with corrugated or simple infill plates subjected to monotonic and cyclic loads. The performance of the corrugated steel plate is evaluated and then compared to that of the simple steel plates by evaluating the damping ratios and energy dissipation capability. The effect of corrugation profile angle, the existence of an opening, and the corrugation subpanel length are numerically investigated after validation of the finite element modeling methodology. The results demonstrate that incorporating corrugated plates would lead to better seismic damping ratios, specifically in the case of opening existence inside of the infill plate. Specifically, the corrugation angle of 30° decreases the ultimate strength, while increasing the initial stiffness and ductility. In addition, the subpanel length of 100 mm is found to be able to improve the overall performance of shear wall by providing each subpanel appropriate support for the adjacent subpanel, leading to a sufficient buckling resistance performance.

Effects of Aspect Ratio and Plate Thickness on the Behavior of Unstiffened Steel-Plate Shear Walls with Pinned and Rigid Connections

Unstiffened steel plate shear walls (SPSWs) have been in use mostly in recent years. In this numerical study, the buckling behavior of a single-storey single-bay unstiffened SPSW with two pinned and rigid beam-column connections under lateral loading is investigated. The SPSW had different wall aspect ratios (L/h=1, 1.5, 2, 2.5, and 3) and infill plate thicknesses (tw= 3, 5, and 7 mm). Their effect on the buckling behavior of SPSW was examined using buckling analysis in ABAQUS software. Results indicated that with the increase of infill plate thickness, the lateral resistance of unstiffened SPSW system increases, but by increasing wall aspect ratio, its resistance decreases. In both connection designs, the model with L/h=1 (square-shaped model) showed better ductility and higher stiffness and strength in all three thicknesses. Maximum shear stress responses of SPSW models showed that in pinned design with L/h=1, the most change in shear stress values was 8% when infill plate thickness reached from 5 to 7 mm; while for rigid connection, it was reported as 7% when it increased from 3 to 5 mm. This indicates that in rigid connection, increasing the infill plate thickness has less effect on the increase of lateral resistance. By examining the performance of rigid and pinned beam-to-column connections with different wall aspect ratio and infill plate thickness, it was found out that maximum shear stress in rigid connection increased by 11% compared to pin connection. It was concluded that an optimum unstiffened SPSW model had a wall aspect ratio of 1 and infill plate thickness of 7 mm.

Experimental and Numerical Research on Steel Plate Shear Wall with Infill Plate Connected to Beam Only

Steel plate shear walls consist of thin infill steel plates attached to beams, called (horizontal boundary elements, HBEs), and columns (vertical boundary elements, VBEs) in structural steel frames. The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action, providing ductility and energy dissipation through tension yielding of the web plate. HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates. VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs. This design approach may result in very large demand on boundary frame members, especially VBEs in most cases. Several methods such as using LYP, perforating the infill plate and omitting connection of infill plate to columns have been proposed to reduce the moment and axial force demands on the VBEs. Study the behavior of steel plate shear walls omitting the connection of infill plate and columns is the main purpose of this research. A classic analysis base on PFI method along with quasi static cyclic experimental study has been performed in order to investigate the behavior of such a system. The results of the experimental study are used to verify numerical models. Behaviors of proposed system (overall capacity and initial stiffness) were compared with those of the conventional SPSWs. Results show that both parameters are reduced in comparison to the conventional SPSWs.

Shaking-table test of a novel buckling-restrained multi-stiffened low-yield-point steel plate shear wall

We proposed a novel buckling-restrained multi-stiffened low-yield-point steel plate shear wall (BR-LYP-SPSW). To study the seismic behavior of BR-LYP-SPSW, a 1:3 scale model shaking-table test was conducted. The increase in the peak ground acceleration decreased the natural frequency and acceleration dynamic magnification factor and increased the damping ratio. The advantage of the sandwiched LYP infill plate is the higher order buckling formed at the LYP infill plate, which played an important role in “the first line of defense.” The maximum inter-storey drifts during frequent and rare earthquakes were 1/694 and 1/88, respectively, which met the demands of the seismic design code of buildings.

Evaluation of the seismic behavior of semi-supported steel shear walls with different ratio and shape of openings

One of the most important advantages of the steel plate shear wall is to create openings with different sizes and arbitrary locations on the infill plate depending on their application. In this study, the effects of the semi-supported steel shear walls (SSSWs) with square and rectangular openings on the seismic behavior of the structural systems are investigated. The ultimate strength, stiffness and energy absorption of the SSSWs are evaluated under non-linear static analysis and cyclic loading for different opening ratios and the results are compared. The results showed that the openings in the walls have a substantial effect on the seismic behavior of the system for different opening ratios and must be considered in the design stage of the buildings.

The wall–frame and the steel–concrete interactions in composite shear walls

SummaryThe nonlinear pushover analyses of 24 composite steel plate shear walls (CSPSWs), 24 corresponding steel plate shear walls (SPSWs), and 24 corresponding frames are conducted. CSPSWs have different aspect ratios and infill steel plate thicknesses. The study aims to understand the wall–frame and steel–concrete interactions. The infill steel plate thickness and aspect ratio of CSPSW are the main parameters of the study.In CSPSWs, the percentage of absorbed shear forces by the infill composite wall is always greater than the infill plate of its corresponding SPSW. The percentage of shear in the composite wall is constant at the initial stage of loading up to a drift of 0.15–0.2%. By increasing the drift, the shear yielding of steel plate leads to a reduction of the shear force absorption. The reduction continues until the bulk of shear stiffness of CSPSW is provided by the frame.At the beginning of lateral loading, steel–concrete interactions increase until shear yield of steel plate. Following this stage, a sudden decrease takes place in shear force absorption of reinforced concrete (RC) panel. The reason is that, at the lower drifts, the steel plate has a tendency for elastic buckling, which is prevented by the RC panel. Finally, the shear force absorption remains approximately constant in the RC panel.

Comparison of the behaviour of steel, pure FRP and hybrid shear walls under cyclic seismic loading in aspect of stiffness degradation and energy absorption

Introducing of light-weight lateral load resisting systems, such as steel shear walls (SSW) is very beneficial for multi-storey buildings. Further improvement of such elements via introducing fibre reinforced polymer (FRP) materials is expected to allow increasing of their ultimate load capacity, stiffness and energy absorption. The aim of presented research is to compare the behaviour of modified SSW via inclusion of FRP in infill plate design. Produced and tested shear wall specimens are three different types: with steel infill plate (control), with FRP infill plate and with hybrid steel/FRP infill plate. All samples are loaded under quasi-static cyclic seismic loading as defined in ATC-24 protocol. The highest ultimate load capacity and lowest stiffness degradation is achieved for sample with glass FRP infill plate, followed by hybrid (carbon FRP/steel and glass FRP/steel) specimens. Highest cumulative energy absorption for predominant part of the investigated amplitudes was achieved for hybrid specimens. The obtained results indicate that the innovative shear walls with FRP and hybrid infill plates offer excellent load carrying capacity and energy absorption, relatively small loss of stiffness and potential for increased durability in comparison with conventional SSW systems.

Cyclic performance of stiffened steel plate shear walls with various configurations of stiffeners

In this study, experiments were conducted on five specimens of stiffened and unstiffened steel plate shear walls under cyclic loading. First, the specimens and frame design, material properties, and test setup were described. The behaviors of the unstiffened aluminum and steel infill plates were compared with three configurations of stiffened steel plate, i.e., cross-stiffened, circular-stiffened, and diagonally stiffened. The cross-sectional areas of the stiffeners were the same for all stiffened specimens. The results showed that the aluminum infill plate exhibited less ductility. By contrast, the unstiffened steel plate was very ductile, exhibiting a stable hysteresis curve and no tearing. The energy-absorption capacity of the steel plate shear walls increased for all stiffening configurations. Among all configurations, the cross-shaped stiffeners showed considerable increase in shear stiffness, ductility, and energy-dissipation capacity. The plate frame interaction method could predict the ultimate shear strengths of the unstiffened and cross-stiffened panels with good precision. The circular-stiffened steel shear wall seems to behave more desirably in high-amplitude displacements.

Numerical study of the cyclic behavior of steel plate shear wall systems (SPSWs) with differently shaped openings

This paper presents the development of finite element (FE) models to simulate the behavior of diagonally stiffened steel plate shear wall systems (SPSWs) with differently shaped openings subjected to a cyclic load. This walling system has the potential to be used for shear elements that resist lateral loads in steel-framed buildings. A number of ½-scale one-story buildings that were un-stiffened, stiffened and stiffened with opening SPSWs are modeled and simulated using the finite element method based on experimental data from previous research. After validating the finite element (FE) models, the effects of infill plate thickness on the cyclic behavior of steel shear walls are investigated. Furthermore, triple diagonal stiffeners are added to the steel infill plates of the SPSWs, and the effects are studied. Moreover, the effects of a number of differently shaped openings applied to the infill plate are studied. The results indicate that the bearing capacity and shear resistance are affected positively by increasing the infill plate thickness and by adding triple diagonal stiffeners. In addition, the cyclic behavior of SPSWs is improved, even with an opening in the SPSWs.

Behaviour of Steel Plate Shear Wall in Multi Span Moment Frame with Various Infill Plate Connection to Column

Steel plate shear walls consist of thin infill steel plates attached to beams, called (horizontal boundary elements, HBEs), and columns (vertical boundary elements, VBEs) in structural steel frames. The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action, providing ductility and energy dissipation through tension yielding of the web plate. HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates. VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs. This design approach may result in very large demand on boundary frame members, especially VBEs in most cases. Several methods such as using LYP, perforating the infill plate and omitting connection of infill plate to columns have been proposed to reduce the moment and axial force demands on the VBEs. The main purpose of this research is to study the behavior of steel plate shear walls with various connection of infill plate to columns in multi span moment frames. A numerical study has been performed in order to investigate the behavior of such a system. The results of proposed system were compared with those of the conventional SPSWs. Results show that reducing the infill plate connection to columns will reduce the axial forces in columns.

Topology optimization of steel plate shear walls in the moment frames

In this paper, topology optimization (TO) is applied to find a new configuration for the perforated steel plate shear wall (PSPSW) based on the maximization of reaction forces as the objective function. An infill steel plate is introduced based on an experimental model for TO. The TO is conducted using the sensitivity analysis, the method of moving asymptotes and SIMP method. TO is done using a nonlinear analysis (geometry and material) considering the buckling. The final area of the optimized plate is equal to 50% of the infill plate. Three plate thicknesses and three length-to-height ratios are defined and their effects are investigated in the TO. It indicates the plate thickness has no significant impact on the optimization results. The nonlinear behavior of optimized plates under cyclic loading is studied and the strength, energy and fracture tendency of them are investigated. Also, four steel plates including infill plate, a plate with a central circle and two types of the multi-circle plate are introduced with equal plate volume for comparing with the results of the optimized plate.