Explore the vast range of titles available.

In recent years, thin-walled, cold-formed steel (CFS) structural members have gained expanding use in building construction and various sorts of structural systems [1,2,3].The utilization Cold-Formed Steel (CFS) structures has become progressively popular in different fields of building technology. The reasons behind the developing popularity of these products include their ease of fabrication, high strength/weight ratio and suitability for a wide range of applications. These advantages can result in more economic designs, as compared with hot-rolled steel, especially in short-span applications. In this project work attempt has been made to use Cold formed steel section as replacement to conventional steel reinforcement bar.

The construction and building sectors are currently responsible globally for a significant share of the total energy consumption and energy-related carbon dioxide emissions. The use of Modern Methods of Construction can help reduce this, one example being the use of cold-formed steel (CFS) construction. CFS channel sections have inherent advantages, such as their high strength-to-weight ratio and excellent potential for recycling and reusing. CFS members can be rolled into different cross-sectional shapes and optimizing these shapes can further improve their load-bearing capacities, resulting in a more economical and efficient building solution. Conversely, the high thermal conductivity of steel can lead to thermal bridges, which can significantly reduce the building’s thermal performance and energy efficiency. Hence, it is also essential to consider the thermal energy performance of the CFS structures. This paper reviews the existing studies on the structural optimization of CFS sections and the thermal performance of such CFS structures. In total, over 160 articles were critically reviewed. The methodologies used in the existing literature for optimizing CFS members for both structural and thermal performances have been summarized and presented systematically. Research gaps from the existing body of knowledge have been identified, providing guidelines for future research.

Full-scale shake table investigations are strongly required to understand the actual performance of storage racks and to improve the rack design guidelines. This paper presents the results of full-scale shake table tests on New Zealand standard storage rack frames with two-bay and two-level to determine the dynamic characteristics of a standard rack structure and to measure the damping of the system. The experimental program was conducted in three phases. First, the identification parameters including the natural frequency and damping of the system were determined through a series of preliminary tests. Then, shake table tests were performed to capture the inelastic response of rack frames under low to medium intensities of El-Centro ground motion. Finally, the shake-table tests were repeated with scaling down the time domain and broader ranges of ground motion intensities to consider the performance of taller rack systems. In addition, a comprehensive discussion on the damping of the system is also provided based on the test results. The performance of the rack frame is described through an extensive set of measurements, including rack displacement, pallet sliding, the acceleration of a concrete block and rack frame and the damping of the system in the down-aisle direction. The results indicate that the standard rack frames are able to endure large inelastic deformations without loss of stability.

Concrete-filled composite columns are widely used in the construction industry, exploiting the benefits of combining steel and concrete, providing, for instance, high load-bearing capacities and enhanced fire resistance. These solutions are extensively used in high-rise buildings and/or when high fire resistance performance requirements are imposed. In this exploratory research, a new type of concrete-filled composite column is investigated using fire resistance tests. Promoting the use of cold-formed steel products and developing innovative solutions for low-rise buildings with lower passive fire protection requirements led to the solutions presented in this research. Hence, a set of fire-resistance tests were undertaken on concrete-filled closed built-up cold-formed steel columns, where single cold-formed steel shapes are combined and fastened to create a box-shaped cross-section. The experimental results were then compared with the corresponding bare steel solutions to assess, in detail, the observed enhancements. Additionally, the effect of restraint on thermal elongation was assessed.

Modular lightweight shear walls can not only facilitate easy installation, thereby improving construction efficiency, but also demonstrate potential to enhance the lateral stiffness when applied in frame structures. The aim of this paper is to investigate the effectiveness of a novel modular cold-formed steel (CFS) shear wall connected with rectangular steel tubes on improving the lateral performance of existing frame structures. Based on the test results of the lateral resistance of four full-scale specimens of modular CFS shear walls connected with rectangular steel tubes, the fine model and simplified model of test specimens were respectively established by the SAP2000v26.0.0 software. The performance indices of the yield load, yield displacement, peak load, peak displacement, and ductility factor were compared, and the maximum error of performance indices was satisfactory. The numerical results show that both the fine and simplified models can well simulate the deformation of walls under lateral cyclic loading, while the simplified models substantially simplify the calculation, which is more adaptable to the subsequent analysis of the multi-story building structure. Then, seismic response analyses of a frame with infilled modular walls and another frame without infilled modular walls were performed. The results indicate that, under the same seismic condition, the lateral displacements of the top floor of the six-story frame with infilled modular walls were reduced by 11–71%, and the maximum inter-story displacement angles were reduced by 15–67% compared to the frame without infilled walls. Therefore, it is demonstrated that the infilled modular CFS shear walls can significantly improve the lateral stiffness and the seismic performance of the steel frame structures.

PurposeThe capability of steel columns to support their design loads is highly affected by the time of exposure and temperature magnitude, which causes deterioration of mechanical properties of steel under fire conditions. It is known that structural steel loses strength and stiffness as temperature increases, particularly above 400 °C. The duration of time in which steel is exposed to high temperatures also has an impact on how much strength it loses. The time-dependent response of steel is critical when estimating load carrying capacity of steel columns exposed to fire. Thus, investigating the structural response of cold-formed steel (CFS) columns is gaining more interest due to the nature of such structural elements.Design/methodology/approachIn this study, experiments were conducted on two CFS configurations: back-to-back (B-B) channel and toe-to-toe (T-T) channel sections. All CFS column specimens were exposed to different temperatures following the standard fire curve and cooled by air or water. A total of 14 tests were conducted to evaluate the capacity of the CFS sections. The axial resistance and yield deformation were noted for both section types at elevated temperatures. The CFS column sections were modelled to simulate the section's behaviour under various temperature exposures using the general-purpose finite element (FE) program ABAQUS. The results from FE modelling agreed well with the experimental results. Ultimate load of experiment and finite element model (FEM) are compared with each other. The difference in percentage and ratio between both are presented.FindingsThe results showed that B-B configuration showed better performance for all the investigated parameters than T-T sections. A noticeable loss in the ultimate strength of 34.5 and 65.6% was observed at 90 min (986℃) for B-B specimens cooled using air and water, respectively. However, the reduction was 29.9 and 46% in the T-T configuration, respectively.Originality/valueThis research paper focusses on assessing the buckling strength of heated CFS sections to analyse the mode of failure of CFS sections with B-B and T-T design configurations under the effect of elevated temperature.

High thin-walled cold-formed steel purlins of the Z cross section are important elements of large-span steel structures in the construction industry. The present numerical study uses the finite element method to analyse the 300 mm and 350 mm high Z cross sections in-depth. The prepared numerical models are verified and validated at several levels with experiments that have been previously published. Significant agreement between the numerical models and the experimental results regarding Mises stress, proportional strain, failure mode, and force-deformation diagram have been obtained. With the verification, the presented procedure and partial findings can be applied to other similar problems. The results can be used to help research and corporate groups optimise the structural design of cold-formed thin-walled steel structures.

The paper presents an overview on research of the influence of perforations on the behavior and capacities of cold-formed steel members, with the most common channel sections. The key findings have been incorporated into American Specification with the development of the Direct Strength Method in design. The paper also introduces the application of the Direct Strength Method in previous studies on the impact of perforations on capacities of cold-formed steel channel members. The overview presented in this paper helps researchers to identify gaps for further investigation. Additionally, the obtained investigated results provide designers in better understanding the effects of perforations on the capacities of cold-formed steel channel members. It was found that there is a reduction in sectional capacities of channel sections with an increase in hole dimensions. Also, reduced hole heights and extended hole lengths are proposed to get optimal section capacities while maintaining the unchanged web hole area in general.

PurposeCold-formed steel (CFS) sections are a popular choice for constructing medium and low-rise structures that are engineered to support relatively light loads. An important characteristic of CFS sections is that they are produced without the use of heat during manufacturing. Consequently, it becomes essential to gain a comprehensive understanding in the behavior of CFS sections when exposed to fire or elevated temperatures.Design/methodology/approachIn this study, sections of 1.5 m length and 2 mm thickness were taken and analyzed to find its flexural behavior after heating them for 60 and 90 min. There were two modes of cooling phase which was considered to reach ambient temperature, i.e. air or water respectively. Performance of each sections (C, C with inclined flanges, sigma and Zed) were examined and evaluated at different conditions. Effects of different profiles and lips in the profiles on flexural behavior of CFS sections were investigated fully analytically.FindingsThe variation in stiffness among the sections with different lipped profiles was noted between 20.36 and 33.26%, for 60 min water cooling case. For the sections with unlipped profiles, it was between 23.56 and 28.60%. Influence of lip and section profile on reduction in stiffness is marginal. The average reduction in load capacity of sections for 60 min specimens cooled by water was found to be 43.42%. An increase in deflection is observed for the sections in the range of 25–37.23% for 60 min case. This is the critical temperature responsible for reduction in yield strength of material as it substantially increases the material safety margin to be considered for the design. Sections with Zed profile have shown better performance among other types, in terms of its load carrying capacity.Originality/valueThis paper deals with the flexural behavior of Galvanized (GI) based CFS unsymmetric sections at elevated temperature and cooled down to ambient temperature with air or water.

This paper conducts a thorough numerical analysis of the performance characteristics of built-up CFS battened beam-columns under bi-axis loading. Based on simulations using ABAQUS with a developed finite element model that accounts for material and geometric imperfections, results show that cross-sectional geometry significantly influences the load-carrying ability of columns, with intricate geometry exhibiting strength values up to 264.57% higher than standard geometry. Compared among steel grades, results reveal the higher ductility and strength of Grade G450 steel, with greater load resistance offered by thicker steel variants (T1.95), up to 430.89%. Notably, the role of Eccentricity in attaining structural performance is recognized, with two-axis Eccentricity reducing load resistance by as much as 94.02%.