Cold-formed high strength steel SHS and RHS beams at elevated temperatures
TL;DR: The structural responses of cold-formed high strength steel (HSS) square and rectangular hollow section (SHS and RHS) beams at elevated temperatures were examined in this paper.
About: This article is published in Journal of Constructional Steel Research.The article was published on 2019-07-01. It has received 30 citations till now. The article focuses on the topics: Flexural strength.
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TL;DR: In this paper, the post-fire mechanical properties of cold-formed steels were investigated using tensile coupon tests and a predictive equation was proposed for evaluating the post fire mechanical properties.
Abstract: Cold-formed steels are commonly used in construction applications. However, there is a lack of understanding on its post-fire mechanical properties. This paper presents an experimental investigation on post-fire mechanical properties of cold-formed steels. The test specimens were cut from flat portion and corners of cold-formed channel sections, which were exposed to temperatures ranging from ambient temperature to 800 °C, and then cooled with water and air. The specimens are of grade Q235, with section thicknesses of 1 mm and 2 mm. The stress-strain curves and mechanical properties of the specimens were obtained from tensile coupon tests. Test results of post-fire mechanical properties are presented. Moreover, evolution of microstructure and fracture morphology of specimens with different cooling methods were examined. Finally, predictive equations are proposed for evaluating the post-fire mechanical properties of Q235 cold-formed steel channel sections.
24 citations
Cites background from "Cold-formed high strength steel SHS..."
...Furthermore, many researchers [10-13] investigated the cold-formed members at various elevated temperatures....
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TL;DR: In this paper , the authors investigated the block shear performance of 16 steel angle specimens connected by double-line bolts and found that the strength of the tension angles could be improved by increasing the tension plane area with the increase of the transverse pitch and edge distance.
Abstract: We investigated the block shear performance of 16 steel angle specimens connected by double-line bolts. Among these specimens, 10 were made of S690 high-strength steel and 6 were made of normal-strength steel. The angle specimens were fabricated using two hot-rolled steel plates through groove welding. Two angle sections, i.e., 125 × 65 × 6 and 125 × 85 × 6 mm (long leg length × short leg length × thickness), were considered in the test. All angles were connected to the long leg. Apart from steel grade, the test parameters included bolt rows, parallel pitch, transverse pitch, edge distance, and unconnected leg length. Typical block shear of specimens were observed, and different fracture patterns were characterised. The test results confirmed that the block shear strength of the tension angles could be improved by increasing the tension plane area with the increase of the transverse pitch and edge distance and increasing the shear plane area with the increase of the bolt row number and parallel pitch. However, the test results showed that the block shear strength of the angles was not affected by the length of the unconnected leg. Subsequently, numerical models were built to further investigate the block shear behaviour of the double-line bolted angles, and the analysis parameters were the end distance, unconnected leg length, and connected leg length. According to the experimental and numerical results, the accuracy and adequacy of design specifications in the United States, Europe, Canada, and Japan and design equations documented in the literature for evaluating the block shear performance of double-line bolted steel angles were evaluated.
19 citations
TL;DR: In this article, the authors conducted 88 steady-state tests on G550 CFS at elevated temperatures and investigated the material properties during the heating and cooling stages of a compartment fire.
Abstract: Steel structures usually experience heating and cooling stages during a compartment fire. Most previous investigations on the high-temperature material properties of cold-formed steel (CFS) focused on the heating stage of steel, corresponding to the growth and fully developed phases of a compartment fire. The influence of the cooling stage of steel, which corresponds to the decay phase of a compartment fire, has not been properly considered. This study conducted 88 steady-state tests on G550 CFS at elevated temperatures and investigated the material properties during the heating and cooling stages. The results show that the prediction of the time-dependent load-bearing capacity of CFS structures under compartment fires might become non-conservative if the material properties of the G550 CFS during the cooling stage are replaced with those during the heating stage. For instance, when the tensile temperature is less than 500 °C and the peak temperature is greater than or equal to 600 °C, the yield strength reduction factors of G550 CFS during the cooling stage are significantly lower than those during the heating stage under the same tensile temperature. In addition, the distribution of the yield strength (ultimate strength) reduction factors of G550 CFS during the cooling stage is affected by the peak and tensile temperatures and displays two branches. The difference in the reduction factors between the two branches is significant under the same tensile temperature and different peak temperatures. Finally, unified equations for the material property reduction factors and stress–strain curves are proposed and can provide a reasonable prediction of the material properties of G550 CFS under full-range compartment fires.
17 citations
TL;DR: In this article, a comprehensive experimental program including a series of standard tensile coupon tests at both ambient and elevated temperatures is described, and key mechanical properties including modulus of elasticity, yield strength, ultimate tensile stress as well as stress-strain curves of the SHP steels are obtained based on the test results.
16 citations
TL;DR: In this article, steady-state experiments on Q345 cold-formed steel (CFS) during the rising and falling temperature periods are presented, and the results show that the material properties of CFS decrease as the load testing temperature increases.
10 citations
References
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13 Jan 2003
TL;DR: Minimum Design Loads for Buildings and Other Structures as mentioned in this paper gives the latest consensus requirements for dead, live, soil, flood, wind, snow, rain, ice, and earthquake loads.
Abstract: Minimum Design Loads for Buildings and Other Structures gives the latest consensus requirements for dead, live, soil, flood, wind, snow, rain, ice, and earthquake loads, as well as their combinatio...
3,751 citations
01 Jul 1943
TL;DR: In this paper, a simple formula is suggested for describing the stress-strain curve in terms of three parameters; namely, Young's modulus and two secant yield strengths.
Abstract: A simple formula is suggested for describing the stress-strain curve in terms of three parameters; namely, Young's modulus and two secant yield strengths. Dimensionless charts are derived from this formula for determining the stress-strain curve, the tangent modulus, and the reduced modulus of a material for which these three parameters are given. Comparison with the tensile and compressive data on aluminum-alloy, stainless-steel, and carbon-steel sheet in NACA Technical Note No. 840 indicates that the formula is adequate for most of these materials. The formula does not describe the behavior of alclad sheet, which shows a marked change in slope at low stress. It seems probable that more than three parameters will be necessary to represent such stress-strain curves adequately.
2,473 citations
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14 Jun 2010
TL;DR: In this paper, the authors defined a set of criteria for the verification of the stability of members with plastic hinges, including tension, tension, compression, and buckling resistance of non-prismatic members.
Abstract: INTRODUCTION General Observations Codes of Practice and Normalization Basis of Design Ultimate limit states Serviceability limit states Durability Sustainability Materials Material specification Mechanical properties Toughness and through thickness properties Fatigue properties Corrosion resistance Geometric Characteristics and Tolerances STRUCTURAL ANALYSIS Structural Modelling, Worked Examples Global Analysis of Steel Structures, Worked Examples Classification of Cross Sections DESIGN OF MEMBERS Tension, Worked Examples Laterally Restrained Beams, Worked Examples Torsion, Worked Examples Compression, Worked Examples Laterally Unrestrained Beams, Worked Examples Beam-Columns, Worked Examples ELASTIC DESIGN OF STEEL STRUCTURES Simplified Methods of Analysis Amplified sway-moment method Sway-mode buckling length method Worked Example Member Stability of Non-prismatic Members and Components Non-prismatic members Members with intermediate restraints General method Worked Example Design Example 1: Elastic Design of Braced Steel-Framed Building PLASTIC DESIGN OF STEEL STRUCTURES 345 General Rules for Plastic Design Plastic limit analysis: method of mechanisms Code requirements for plastic analysis Methods of Analysis Approximate methods for pre-design Computational analysis 2nd order effects Worked Example Member Stability and Buckling Resistance General criteria for the verification of the stability of members with plastic hinges Bracings Verification of the stability of members with plastic hinges Worked Examples Design Example 2: Plastic Design of Industrial Building REFERENCES
1,143 citations
TL;DR: In this article, the authors developed an expression for the stress-strain curves for stainless steel alloys which is valid over the full strain range, which is useful for the design and numerical modelling of stainless steel members and elements which reach stresses beyond the 0.2% proof stress in their ultimate limit state.
730 citations
TL;DR: A series of experimental tests on stainless steel beams is presented in this paper, which includes tests to determine the stress-strain relationship of the material, considering the effects of cold work, and a comparative analysis between the experimental results of deflections and those results derived from a numerical model considering material non-linearity.
417 citations