Height-thickness Ratio Research Articles

Stability of cold-formed steel stud walls subjected to vertical compression

Cold-formed steel (CFS) stud walls are the primary vertical load-bearing units in CFS residential systems. These walls need to meet both strength requirements and good stability. In this study, a CFS stud wall was simplified into a mechanical model of an orthotropic plate rib system using the orthotropic plate (OP) method. A formula for calculating the equivalent stiffness of the stud wall was obtained, and the correctness of the simplified calculation model and equivalent stiffness calculation formula was verified by finite element analysis. Various factors that affected the equivalent stiffness of the wall were investigated. Additionally, the stability of the stud walls under a vertical load was derived by considering the stability theory of the plate. The results indicated that the stability of the stud walls was mainly related to the height-thickness ratio of the walls. Finally, the correction factor of the allowable height-thickness ratio of the walls was obtained by analyzing the parameters of the wall thickness, stud spacing, sheathing materials, and wall opening, and a case study was used to illustrate the procedure of this simplified method.

Average surface wind pressure surrounding tall buildings with cruciform shapes

Abstract Building shape affects wind pressure on building surfaces, while limited studies have examined how building shape affects the wind pressure on cruciform-shaped tall buildings. This article investigated the variation of the average wind pressure coefficient (AWPC) on cruciform-shaped tall buildings with the height–width ratio (HWR) and height–thickness ratio (HTR). The results demonstrated the occurrence of building blockage, wind separation, wind re-circulation, and wind re-attachment on building surfaces. The frontal surface of the main building was always the windward surface with positive wind pressure. At 2/3 of the building height (H), the peak AWPCs in all scenarios were ~0.70. However, in the case with an HWR of 3.66, the side surfaces of the main building and the frontal surfaces of the branch building, wind pressure was all negative. With the HWR reduction by building width increase, wind pressure on these surfaces became positive, where the AWPCs in the HWR = 1.41 case were 0.60–0.63 and 0.64–0.69 on side and frontal surface, respectively. With the HWR decrease, both positive and negative wind pressure intensified. Along the central axis (M1) in the vertical direction, wider buildings had stronger positive wind pressure on the frontal surfaces below 0.10H, while narrower buildings had stronger positive wind pressure above 0.82H. In comparison, HTR made limited differences to the wind pressure on the frontal surface. Overall, vertical results showed that scenarios with smaller HWR underwent stronger positive and negative wind pressures. On the HTR cases, wind pressure on top surfaces showed complicated results, while thicker buildings had weaker negative wind pressure on the back surface. Overall, this study is important to understand the characteristics of wind load on cruciform-shaped tall buildings and generate implications for wind resistance, natural ventilation design, and wind electricity generation over tall buildings.

Structural Behavior of a Fixed-End Arched Cellular Steel Beam without Lateral Support

The arched cellular beam has the advantages of both the solid-web arch and the straight beam with web opening, and has become increasingly admired by architects in recent years. In this paper, four arched cellular beam specimens are designed using an orthogonal test method (OTM) with a three-factor and two-level approach. Firstly, the static loading test is carried out to analyze the mechanical response of the arched cellular beam under concentrated load. Then, a numerical analysis based on ABAQUS finite element (FE) software is carried out. The results show that the simulation results agree well with the test results, which indicates the accuracy of the simulation analysis method. Finally, the buckling load of the arched cellular beam under three different loads is calculated using the variable parameter FE analysis. Combined with the range analysis in the OTM, the influence of the target factor on the buckling load of the arched cellular beam is determined. The results show that the order of the factors affecting the out-of-plane elastic buckling is rise–span ratio > web height–thickness ratio > diameter–depth ratio.

Experimental and numerical study on hysteretic behaviour of corrugated steel plate shear walls under lateral loads

This paper presents experimental and numerical investigations of the hysteretic performance of the corrugated steel plate shear wall (CSPSW) subjected to lateral loads, and proposes an effective hysteretic model for the CSPSW with interactive buckling or yielding of the corrugated steel plate (CSP). First, a cyclic loading test for a CSPSW with interactive buckling was conducted. The CSPSW test specimen exhibited high strength, lateral stiffness, and good energy dissipation capacity. In accordance with the cyclic test, a numerical model was developed to simulate the hysteretic behaviour of the CSPSW. Subsequently, extensive parametric analyses were performed to investigate the effects of the concerned geometry parameters on the hysteretic performance of CSPSWs, such as the height–thickness ratio, aspect ratio, corrugation angle, horizontal subpanel width and surrounding frame stiffness. The available limits of the height–thickness ratio, aspect ratio and surrounding column stiffness for CSPSWs were suggested. Based on the experimental and numerical results of the hysteretic curves and theoretical derivations, a hysteretic model for a CSPSW with interactive buckling or yielding of the CSP was proposed and verified by tests and finite element models. The results showed that the proposed hysteretic theoretical model can reproduce the hysteretic performance of CSPSWs with reasonable accuracy.

Seismic Performance Analysis of Corrugated Steel Plate Shear Wall Connected with Beams Only

This paper studied the seismic performance of corrugated steel plate shear walls with vertical corrugated steel plates connected with beams only (CboSPSWs). A numerical model of a CboSPSW was developed. Then, a series of parametric analyses were conducted to determine the effects of the related parameters on the hysteretic performance of CboSPSWs, including the height–thickness ratio, aspect ratio, corrugation angle, stiffness of the free-edge stiffener, and surrounding frame stiffness. In addition, the limit of the stiffness of the free-edge stiffener of the CboSPSW was investigated. Finally, the serviceability of the existing design method, the Plate-Frame Interaction model (PFI), for CboSPSWs was examined. The results show that CboSPSWs have high values of strength and initial stiffness as well as good and stable energy dissipation capacities. The ultimate strength of the corrugated steel plate (CSP) can be improved significantly by free-edge stiffeners. When the flexural stiffness ratio exceeds 1.0, the increase of the average stress of the CSPs close to the beams is less than 20%, and the tension field develops fully in the CSPs in CboSPSWs. The PFI model can predict the shear strength and initial stiffness values of the hysteretic curves of CboSPSWs with good accuracy, which can be used in the design and plastic analyses of CboSPSWs.

Shear Behavior and Analytical Method of Vertically Corrugated Steel Plate Shear Walls with Inelastic Buckling of Infilled Plates

This paper presents numerical investigations of the shear performance of vertically corrugated steel plate shear walls (CvSPSWs) with inelastic buckling of infilled plates under lateral loads. A numerical model was developed and verified by an experiment. Subsequently, a series of parametric analyses were conducted to investigate the effects of the concerned parameters on the shear performance of CvSPSWs, such as the connection type, height–thickness ratio, aspect ratio, horizontal subpanel width, and surrounding beam stiffness, in which the loading mechanism, buckling behavior, and failure modes of the corrugated steel plate (CSP) in the CvSPSW were discussed. The results show that CvSPSWs exhibit large initial stiffness, in-plane and out-of-plane strength, and good displacement ductility. Further, a formula for predicting the buckling strength of the CSP in the CvSPSW is proposed, and the effect of the section stiffness of the inclined subpanel on buckling strength and the development of the tension field of the CSP was investigated. In addition, simplified analytical models for CvSPSWs were examined to simplify the elastoplastic analysis of CvSPSWs. The results show that the plate-frame interaction model and the modified strip model can reproduce the shear performance of CvSPSWs with good accuracy.

Research on ultimate Bearing Capacity of large Steel Box Girders under bending Moment

In order to study the ultimate bearing capacity of large welded box girder with initial imperfections, this paper considers the influence of material nonlinearity, geometric nonlinearity and initial imperfections, and uses the arc length increment method to modify Newton-Raphson formula to solve the problem. Through a large number of numerical simulation calculation, the calculation formula of stability ultimate bearing capacity of box girder under bending moment is summarized. The formula takes web height thickness ratio and flange width thickness ratio as parameters, which has a certain reference value for calculation and design of stability ultimate bearing capacity of welded box girder.

Numerical analysis on fire performance of sandwich composite wall with truss connectors

Based on the previous experimental study on sandwich composite walls with truss connectors under axial loads and one-side fire, finite element analysis was conducted on the fire performance of the novel wall in this paper. Firstly, a thermal coupling analysis model was established for the sandwich composite wall by the finite element software ANSYS, and simulation of test results was performed. The comparison between the predicted results and the test results showed that this model could accurately simulate behaviors of sandwich composite walls under fire. The validated finite element analysis model was utilized to carry out parametric analysis on the fire performance of the sandwich composite walls under one-side fire and two-side fire, respectively. Results showed that wall thickness is a major parameter affecting the fire resistance of the wall under one-side fire. The axial compression ratio, the height-thickness ratio and the wall thickness are major parameters influencing the fire resistance of the wall under two-side fire. Equations for predicting the fire endurance of sandwich composite walls were obtained, by fitting with the major affecting parameters. The calculated results from the equations were in good agreement with the results from the finite element simulation, and the equations can be used as a reference for the fire-resistant design of sandwich composite walls.

Experimental Study on Steel Plate Shear Walls with Partially Encased Composite Columns Composed of Thin Steel Plate

The steel plate shear wall structure has excellent seismic performance, mainly consists of embedded steel plate, horizontal boundary elements (HBEs) and vertical boundary elements (VBEs). Under the action of additional bending moment, the VBEs of SPSW often produce the failure mode of “hourglass specimen”. As a solution, the SPSWs proposed in this paper adopts PEC columns, which are composed of concrete filled between flanges of thin-wall channel steel, and transverse steel bars welded between flanges to prevent it from buckling. A slow cyclic test was conducted on two specimens of 1/3-scaled prefabricated SPSWs with thin steel plate composite section PEC column. According to the validated finite element method, the parameters including the height-thickness ratio of filled steel plate, concrete strength grade, bolt spacing and axial compression ratio were also studied. The results show that the new structure has high bearing capacity and good ductility. In addition, the PEC column has enough stiffness to form a good anchoring effect for the inner steel plate. The inner steel plate fully yields after buckling and provides bearing capacity and energy consumption through the action of tension field. The peak load of specimens with concrete has a higher level approximately 18% than the no-concrete specimen. The height-thickness ratio has a great impact on the post buckling performance of SPSWs. With the increase of height-thickness ratio, the ultimate bearing capacity of the structure will increase by 10% – 30%. Moreover, to give full play to the outstanding performance of prefabricated SPSW with PEC column, the value range of bolt spacing is suggested to be in the range of 120 mm – 60 mm.

Nonlinear patch resistance performance of hybrid titanium-clad bimetallic steel plate girder with web opening

Titanium-clad bimetallic steel (TCBS) is a new type of structural steel, which consists of TA1 cladding with outstanding corrosion resistance and Q235 mild steel base with good mechanical properties. Corrosion weakens the thickness of plates in steel members, which reduces the resistance capacity. The web thickness of the plate girder is relatively thin. Hence, the web is more prone to be weakened due to corrosion. To resolve the above issue, an innovative configuration of introducing TCBS into the plate girder as the web was proposed. The monotonic tensile coupon test results stated that TCBS has no evident yield plateau in its stress-strain curve. An experiment was conducted to investigate the nonlinear resistance performance of the hybrid TCBS girder under patch loading. After the experiment, the wave bending deformation of the web exhibited an axisymmetric distribution, where a tensile field was formed. The plastic hinge was formed in the loading area on the flange. No delamination or cracking in the TCBS was observed. A numerical modeling method for the hybrid TCBS plate girder under patch loading was established. Subsequently, a parametric study of the hybrid TCBS plate girder under patch loading was conducted using the proposed numerical modeling method. The effects of the material model, web opening location, web aspect ratio, height–thickness ratio, and loading location on the resistance behavior of the hybrid TCBS plate girder were thoroughly investigated.

Experimental and nonlinear analytical investigation of the flexural performance of single-box double-chamber steel–bamboo composite beams

Steel–bamboo composite structures present excellent and stable engineering performance. This study presents a novel single-box double-chamber steel–bamboo composite beam consisting of cold-formed thin-walled steel and bamboo scrimber. Nine single-box double-chamber steel–bamboo composite beams were prepared with various section parameters. A four-point bending test was conducted to evaluate the flexural behaviour of the beams. The failure mode, deflection deformation, and load-carrying capacity were analysed based on the test phenomena and data; the influences of the various parameters on the flexural behaviour were explored. Finally, nonlinear analytical models were developed considering the nonlinear constitutive law of beams and the influence of the steel–bamboo interface slip. The results indicated that lateral instability and local buckling behaviours were effectively avoided, and two failure modes were identified. The bending resistance was improved by reducing the flange bamboo width–thickness ratio, steel height-thickness ratio, and increasing the height of the web. The bending capacity depended more on the bamboo than that on steel. The nonlinear analytical models provided accurate predictions for the beams with tensile failure. Discrepancies between the experimental and analytical results were less than 8.6%.

Experiments on local–distortional interaction buckling of cold-formed steel three-limbed built-up open-section columns

Cold-formed steel built-up open-section members, which are widely used in doorways, window frames, and corners, exhibit low torsion stiffness and high susceptibility to the deformation of the cross-section. Extensive research has been conducted on the pure buckling behaviour of cold-formed built-up members. However, few studies have investigated the local–distortional buckling interaction behaviour of complex built-up sections. This study aims to obtain a thorough understanding of the mechanics of three-limbed built-up open-section columns undergoing local–distortional interaction buckling through experiments and numerical simulations. Six lipped channels and 18 built-up columns were axially compressed under fixed boundary conditions. Finite element models were established and verified. Detailed parametric studies were conducted on the validated finite element models by varying the web height–thickness ratio, screw spacing, and slenderness ratio. The experimental results indicate that the studied built-up section had an evident assembly effect, and the bearing capacity of the built-up open-section column was sensitive to the web height–thickness ratio. Additionally, the numerical results show that, under local–distortional interaction buckling, the screw spacing had a minor influence on the ultimate bearing capacity of the three-limbed built-up open-section columns. The columns buckled in local–distortional interactions, with slenderness ratios ranging from 12.73 to 36.30. Finally, the validity and accuracy of the local–distortional​ interaction buckling calculation methods considering three-limbed built-up open-section columns were evaluated. With the current calculation methods, the prediction of the local–distortional buckling capacity of three-limbed open-section built-up columns is conservative.

Experimental study and numerical simulation on the seismic behavior of diagonally stiffened stainless steel plate shear walls under low cyclic loading

To expand the application scope of stainless steel, especially in the seismic resistance, a series of systematic studies from material to members were carried out. A mechanical property test of S30408 austenitic stainless steel under monotonic loading and cyclic loading was conducted first. Then, a low cyclic loading test of 8 diagonally stiffened steel plate shear walls (SPSWs), including 6 stainless SPSWs, 1 LY100 low-yield-strength SPSW and 1 Q235 SPSW, was carried out. The failure modes, hysteresis curves, skeleton curves, ductility coefficient and equivalent viscous damping ratio-displacement angle curves of different SPSWs were compared. The mechanical behavior, energy dissipation and failure mechanism were revealed. The test results showed that the ductility of stainless SPSWs was the greatest. An effective tension field was formed after buckling. Even if the displacement angle exceeded 1/50, a good bearing capacity was displayed. A corner tearing for the LY100 and Q235 SPSWs occurred in the late stage of loading, resulting in a failure to form a reliable tension field. A notable decline in bearing capacity occurred, and the ductility was poor. The energy dissipation of the stainless SPSWs was better than that of the Q235 SPSW but slightly worse than that of the LY100 SPSW. Considering the limitation of the test, such as the limitation of the specimen number and the range of the investigation parameters, a refined finite element model was established and a parametric analysis was conducted, mainly considering the influence of aspect ratio α, height-thickness ratio λ, stiffness ratio of periphery stiffener ηf and stiffness ratio of diagonal stiffener ηs on the hysteretic performance. The research carried out herein offers a reliable reference for this new lateral force resisting structure and provides data for subsequent research, which is helpful to promote the application of stainless SPSWs in building structures.

Fire resistance design of austenitic SUS316 stainless columns subjected to axial compression

To explore the effect of cold-working on the properties of austenitic stainless steel, a material mechanical property test of austenitic SUS316 stainless steel coupons extracted from cold-formed RHS columns at elevated temperatures was conducted. Based on the fire test of 5 austenitic stainless SHS columns subjected to axial compression, a refined finite element model was established. A single parametric analysis of different parameters, cross-sectional area, height-thickness ratio, initial overall imperfection, eccentricity, slenderness ratio, aspect ratio and load ratio was conducted, mainly investigating the effects on the critical temperature and maximum axial displacement. As the effect of the load ratio was the most significant, a multiparameter analysis of the load ratio with other parameters was further conducted. Presently, the design methods in EN 1993–1-2 for carbon steel columns are also applied to stainless steel columns, where section classification is needed. Based on numerous parametric analyses, the design methods in EN 1993–1-2 were assessed and modified. EN 1993–1-2 underestimated the bearing capacity of stainless steel SHS and RHS columns, and the modified method improved the utilization rate of stainless steel. A new method for evaluating the bearing capacity of stainless SHS and RHS columns using the maximum axial displacement was proposed, for which the section classification was not needed. As a preliminary study, the new method was only applicable to stainless SHS and RHS columns with load ratios between 0.2 and 0.6, which was also the most commonly applied scope in engineering.

Cyclic behaviour of diagonally stiffened stainless steel plate shear walls with two-side connections: Experiment, simulation and design

Stainless steel has good ductility and energy dissipation, which is very suitable for steel plate shear walls. However, there is no report on stainless steel plate shear walls. Therefore, based on a completed low cyclic loading test of 6 diagonally stiffened S30408 austenitic stainless steel plate shear walls, a refined finite element model of the test specimens is established using ABAQUS software. Then, a large number of parametric analyses are conducted mainly considering the influence of the aspect ratio α, height-thickness ratio λ, stiffness ratio of the periphery stiffener ηf and stiffness ratio of the diagonal stiffener ηs on the elastic buckling stress. A simplified formula for calculating the elastic buckling stress of diagonally stiffened stainless steel plate shear walls with two-side connections is proposed. Based on the experimental study, parametric analysis and theoretical derivation, a resilience model of diagonally stiffened stainless steel plate shear walls is proposed. Finally, to facilitate the engineering design, a simplified resilience model and design method of stainless steel plate shear walls are proposed. The research herein illustrates the differences of cyclic behaviour between stainless steel plate shear walls and other steel plate shear walls and provides an accurate design method for the first time.

In-Plane Interactive Buckling of High Strength Steel Welded Wide Web I-Section Beam-Columns

A numerical investigation on the overall-local interactive buckling performance of high strength steel (HSS) wide web I-section members was conducted using finite element (FE) models verified against experimental data. The effect of overall slenderness, the height-thickness ratio of the web h w / t w , and the width-thickness ratio of the flanges (bf/tf) on ultimate load was parametrically analyzed. The result demonstrated that (i) for the beam-columns with higher steel grade, the Pz-Uz curve presents a relatively obvious deformation plateau, meaning a certain degree of ductility. (ii) The ultimate load decreased essentially linearly resulting from higher h w / t w , and the trend was graphically consistent under various steel grades. (iii) bf/tf lower than 0.6 led to the failure mode of shearing buckling, and the corresponding ultimate load increased with an increase of bf/tf. In the case of bf/tf greater than 0.6, the ultimate load decreased as a result of the higher bf/tf. Based on the concept of the direct strength method, the local postbuckling strength prediction formula was fitted with stub beam-column FE results and examined with experiment data. The correlation formula of compression and bending moment was proposed to evaluate the resistance of the interactive buckling of the HSS wide web I-section underpinned by the FE results of beam-columns with intermediate length and experiment data.

Experimental Study on Compressive Strength of Ultrahigh Performance Concrete Prefabricated Wall Structure

In order to study the influence of two parameters, height-thickness ratio and reinforcement ratio, on the compressive performance of prefabricated recycled concrete block-filled core walls, the author proposes a test method for the compressive strength of wall structures. In this method, 9 walls of dry and full-fill masonry are used, and the test measuring device and the arrangement of measuring points are designed to carry out the loading test. The results showed that reinforcement can significantly improve the axial compressive bearing capacity of the wall, but the out-of-plane displacement of the unreinforced wall is smaller than that of the reinforced wall. The larger the height-to-thickness ratio, the better the ductility of the reinforced core wall; the measured value of the axial compressive bearing capacity of the core-filled wall and the mean and coefficient of variation of the ratio to the standard calculated value were 1.49 and 0.13, respectively. The measured value is 34% to 68% higher than the standard calculated value. In conclusion, based on the test data and GB 50003–2011 “Code for Design of Masonry Structures,” the theoretical calculation formula of the compressive bearing capacity of the prefabricated recycled concrete block-filled core wall is given.

Shear capacity investigation of steel-concrete composite girders in hogging moment regions

Slender steel-concrete composite girders are commonly used in bridge structures; however, the influences of web shear-buckling and concrete slabs on the shear strength of these girders have rarely been investigated thus far. In this study, an experimental and numerical investigation was condcuted to determine the ultimate shear strength of slender composite girders in hogging moment regions. Six simply-supported composite girders and a bare-steel girder were experimentally subjected to combined negative moment and shear. In addition, the influences of the moment/shear ratio, web height–thickness ratio, concrete slab thickness, and web aspect ratio on the failure modes, web elastic buckling loads, ultimate loads, and web out-of-plane deformations of composite girders were investigated. Moreover, a nonlinear finite element (FE) model was developed and verified using the experimental results, and the verified FE model was used to conduct the parametric analysis. The results revealed that the shear strength of the composite girders in hogging moment regions increased linearly with the thickness, longitudinal reinforcement ratio, and width of the concrete slab, among which the slab thickness posed the greatest effect, followed by the reinforcement ratio, and lastly, the slab width. Furthermore, an equation was proposed based on the web shear-buckling and the concrete slab shear contribution to express the shear strength of composite girders in hogging moment regions. Conclusively, the proposed equation was validated with the experimental and numerical results.

Research on shear performance of corrugated steel plate shear walls with inelastic buckling of infilled plates under lateral loads

The corrugated steel plate shear wall (CoSPSW) system has potential in resisting lateral wind and seismic loads in high-rise buildings. This paper presents a numerical and theoretical investigation of the shear behaviour of CoSPSWs with inelastic buckling mode of the corrugated steel plate (CSP) subjected to lateral loads. The geometry parameters of CoSPSWs with inelastic buckling of infilled plates were derived theoretically. In addition, a series of finite element analyses was conducted to simulate the performance of CoSPSWs. Parametric analyses were performed to examine the effects of key geometry parameters, such as the height–thickness ratio, aspect ratio, horizontal panel width, and corrugation angle, affecting the buckling and failure modes and the strength of CoSPSWs. Then, the demand of the surrounding frame stiffness of the CoSPSWs was investigated based on the tension field distribution of CSPs. Finally, a modified strip model was designed to predict the shear performance of the CoSPSWs. The results revealed that the CoSPSWs, owing to the tension field effect, could resist greater loads after the inelastic buckling of infilled plates. However, the height–thickness ratio and aspect ratio should be restricted during the design of tall buildings. In addition, a formula for predicting the stiffness demand of the CoSPSW was derived. The results of the modified strip model agreed well with the previous experimental data.

Research on Bearing Capacity and Ductility of CFSST with Stiffeners

In order to investigate the bearing capacity and ductility of concrete-filled square steel tubular (CFSST) with longitudinal stiffeners in condition of instant steel ratio, six specimens, including 1 CFSST, 3 CFSST with single stiffener and 2 CFSST with double stiffeners, were fabricated and tested. And the FEM was established and simulated by ANSYS. The experimental result showed that when the height-thickness ratio of stiffeners was increased, the bearing capacity would be generally decreased but the ductility could be improved. Besides, the specimens performed identical mechanical characteristics while the thickness of steel was the same. And the results of FEM were basically identical to the experiments. Finally, the confinement ξ played a key role to predict the bearing capacity.