Cold-formed Steel Composite Wall Research Articles

Novel self-centering cold-formed steel composite wall: Concept, theoretical analysis, and numerical investigation

Cold-formed steel (CFS) structures exhibit considerable superiority in efficient and environmentally friendly building construction in high-seismic regions. The objective of this study is to develop and validate the concept of self-centering cold-formed steel composite (SC-CFSC) wall structures, and to characterize the lateral behavior of an SC-CFSC wall through numerical and theoretical analyses. Based on tests on shape memory alloy wires and CFSC walls, their hysteretic behavior is applied in ABAQUS to construct a finite element (FE) model of an SC-CFSC wall. The FE and theoretical analysis results of the SC-CFSC wall are in reasonable agreement, and valuable information regarding the design of the SC-CFSC wall is summarized. This study not only aims to provide a novel concept of self-centering CFS structures, but also to provide comprehensive explanation regarding the theoretical derivation and simulation procedures for characterizing the lateral behavior of both CFSC and SC-CFSC walls.

Numerical modeling on shear performance of braced cold-formed steel composite walls

In this paper, the specific influence of diagonal braces on the hysteretic behaviors, including lateral stiffness, yield load, and load-bearing capacity, of braced composite cold-formed steel (CFS) walls have been investigated through the combination of previous experiment results and numerical analysis. A detailed modeling method using connector function in ABAQUS for simulating single screw connection has been introduced. Furthermore, the finite element models based on experimental specimens have been constructed, an excellent match of finite element analysis and experimental results are yielded to prepare for parametric analysis; five significant parameters, vertical load, panel splice type, screw spacing, section thickness of end studs, and diagonal braces, were considered in parametric analysis to in-depth investigate the hysteretic behavior of walls. Finally, some valued conclusions expected to be benefited engineering applications have been summarized.

Cyclic performance of steel frame fabricated with cold-formed steel composite wall structure

In this study, a novel hybrid wall structure of a hot-rolled steel frame fabricated with a cold-formed steel (CFS) composite wall is proposed. Ceramsite concrete is lightweight concrete that is used in CFS composite walls. The seismic performances, including the failure mode, hysteretic behavior, shear capacity, stiffness, ductility, and energy dissipation performance, of four specimens of steel frame fabricated with CFS composite wall and one specimen of conventional CFS composite wall were evaluated under low-cyclic loading. The experimental results showed that the collaborative working performance of the steel frame and infilled CFS composite wall was optimum, and the proposed fabricated wall structure had a significant effect on the bearing capacity, stiffness, and energy dissipation capacity. The infilled CFS composite walls were damaged earlier than the steel frames. The damage was primarily characterized by the compressive failure at the corners of fillers, loss of diaphragm effect, screw connection failure, and bond-slip failure between the CFS framing and fillers. However, the steel frames exhibited no obvious damage, which effectively restrained the infilled CFS composite walls and prevented them from severe collapse. In addition, enhancing the strength of the fillers and increasing the section area of the studs improved the bearing capacity of the structure; however, they were detrimental to the ductility. Wall opening reduced the bearing capacity and initial stiffness of the structure; however, it improved the ductility. Furthermore, a superposition method was used to calculate the bearing capacity of the proposed structure. The calculated results showed a superior accuracy in comparison with the experimental results.

Experiment investigation on lateral performance of CFS composite walls sheathed with magnesium crystal board

Cold-formed steel (CFS) walls with novel sheathing have been of growing interest in hysteretic behavior. This study investigated the effect of diagonal bracings and sheathing magnesium crystal boards (MCBs) on the hysteretic behavior of CFS walls. Furthermore, a novel refined vertical loading system was proposed to solve the key problems caused by conventional distribution beam loading systems. Monotonic or hysteretic loading was conducted on six full-size CFS walls sheathed with MCB and one pure CFS frame wall to obtain the failure modes, yield loads and corresponding displacements, peak loads and corresponding displacements, and lateral stiffness of the specimens. Finally, the failure mode of the MCB located in the vertical seam was observed and discussed, and the influence of the flexible diagonal brace on the lateral bearing capacity and ductility of the CFS wall was further analyzed.

Simplified calculation of fire resistant temperature for cold-formed steel load-bearing composite walls

The research on the fire resistance design of cold-formed steel (CFS) load-bearing composite walls, as the main vertical load-bearing and space-dividing components of the CFS structure, has received widespread attention. The purpose of this article is to propose a formula for calculating the fire resistant temperature of CFS composite walls in order to simplify the design method. Three different configurations for composite wall lined with gypsum plasterboards which commonly used were chosen as research objects. According to the temperature-rise rule and heat transfer mechanism, the temperature-rise curves at hot flange of the studs were obtained. Then a heat transfer model was established with considering both the heat conduction and cavity radiation where obtained temperature load was applied at hot flange of the stud to calculate the temperature distribution of the wall cross-section. The improved heat transfer model not only considered the effect of cavity radiation, but also simulated the direct exposure of the stud to high temperature due to the falling-off or losing of insulation for sheathed board. Then the heat transfer calculation results were imported into a simplified mechanical model for thermal–mechanical coupling numerical simulation. Integrity, insulation, and the load bearing capacity of the stud cross section were taken as the comprehensive consideration criteria for composite wall failure. The temperature at hot flange of the stud was defined as fire resistant temperature when the composite wall damaged. Finally, load ratio and fire resistance temperature related calculation formulas were fitted from the results of transient thermal–mechanical coupling simulation with varying load ratios. The comparison of fire resistance temperature between fitting formula and fire test results verified the applicability of the proposed fire resistance temperature calculation formula. Compared with the fire resistance temperature calculation formulas in the existing literature, the calculation formula proposed in this paper was more accurate and reasonable.

Study on the Influence of the Thickness of Column on Axial Compression Behavior of Cold-Formed Steel Composite Wall

By changing the thickness of the column, the axial compression behavior of the one-side sheathed wall and the both-sides sheathed wall can be altered at different levels. Simulation and inspection of cold-formed thin-walled steel frame wall had been finished by using a finite element simulation software called ABAQUS, which was applied by test data from relevant literature. The axial carrying capacity of the sheathed wall was superior than the unsheathed wall, therefore, all models had been built and studied based on the one-side sheathed wall and both-sides similar sheathed wall. The analysis results proved that the axial compression behavior of the one-side sheathed wall and the both-sides sheathed wall could be increased substantially by adding the thickness of studs, and this change was more sensitive to the influence of the wall with one-side sheathed wall especially.

Study on Hear Resistance of Cold-formed Steel Composite Wall with Openings

In order to study the shear resistance of cold-formed steel wall with openings, a numerical model of the specimen for cold-formed steel wall with openings shear test was established using Opensees software, which was used to simulate its shear resistance under cyclic loading. On this basis, the parameters of the factors affecting the shear resistance of cold-formed steel wall with openings were analyzed. The results show that the contribution of the coupling beam to the shear performance of the whole wall is reduced with the increase of the span-depth ratio of coupling beam. When span-depth ratio of the coupling beam is greater than 5, the contribution of the coupling beam to the shear resistance of the wall is ignored. The ratio of opening to wall and the ratio of window to wall have a great influence on the shear resistance of cold-formed steel wall with openings, and the influence of each factor on the shear performance of the cold-formed steel wall with traditional side column is greater than that of the cold-formed steel wall with reinforced end studs. The stiffness of the side column has little effect on the shear resistance of the cold-formed steel wall with openings.

Simplified calculation model for load-bearing cold-formed steel composite walls under fire conditions

The conventional simplified model only restricts the bending buckling around the minor axis and overall torsional buckling, which is not suitable for external sandwiched cold-formed steel composite walls. Moreover, a solution to stud–track connections must be achieved in establishing the overall structure model. In this article, a simplified calculation model is proposed to accurately and efficiently reveal the fire performance of cold-formed steel composite walls. A tension spring is adopted to simulate the boundary condition that limits the axial thermal expansion of the studs at elevated temperature. Meanwhile, the simplified applications of the panel constraints and stud–track connections are also given in details. Finite element analysis using the developed simplified calculation model is conducted to simulate five full-scale cold-formed steel composite walls with different configurations. Comparisons between the finite element analysis and fire test results show an overall agreement on the failure modes, cold flange temperatures and lateral deflections at mid-height of the studs. These results demonstrate that the developed simplified calculation model is able to simulate the fire performance and predict the lateral deflection of the external sandwiched cold-formed steel composite walls accurately. Finally, the key factors affecting the lateral deflection of the studs are analysed.

Study on Shear Performance of Cold-formed Steel Composite Wall with New Type of stud

The shear resistance of single oriented-strand board wall and single gypsum board wall can be improved in different degrees by increasing strength of steel. The experimental data of literatures were used, and the test specimens had been simulated and validated by ABAQUS finite element analysis. According to the research, it showed that the compressive bearing capacity of the new stud composite wall was much better than the common stud composite wall, so the establishment and research of all models had been based on the new section stud. The analysis results show that when using new type of stud the shear resistance of the single oriented-strand board wall can be improved efficiently by increasing strength of steel, but the shear resistance of the single gypsum wall can be increased little.

The Finite Element Analysis of Effect Factor about the Shear Behavior of Cold-Formed Steel Composite Wall

This paper adopts the finite element method to study the shear resistance of the first floor cold-formed steel composite walls in six stories residential structures, plastic shell element is used, materials nonlinearity and geometric large deformation are considered. The screws connecting sheathing and frame are modeled through coupling methods. Analyzing the influence of factors such as stud spacing，Brace and rigid bracing's establishment，component wall thickness to the shear behavior of cold-formed steel composite wall， these dates can provide certain theory for the actual project.