This paper is focused on stainless steel square and rectangular hollow section (SHS and RHS) slender members loaded by a combination of compressive force and the bending moment. The study presents ...tests on 20 members, including initial imperfection measurements and material coupon tests. The tests take into consideration uniaxial bending to the major axis. The data obtained from the experimental study were subsequently used for validating an FE numerical model. A comprehensive numerical parametric study was carried out on all three common structural stainless steel groups: austenitic, ferritic and duplex. The cross-section slenderness and the cross-section aspect ratio (h/b), the non-dimensional member slenderness, the material stress–strain diagram (yield strength, ultimate strength, degree of non-linearity) and the ratio between the compressive force and the bending moment were set as the main parameters. Results of the numerical parametric study were compared with some of the existing procedures for stainless steel beam–column design. The main focus is on the proposal developed by Zhao et al., which is the procedure expected to be used in the new EN 1993-1-4. Although the method published by Zhao et al. has shown good prediction ability, a new design approach was proposed and its suitability demonstrated by a reliability study. The method is believed to be more general, as it uses a single formula for all grades of stainless steel, and also covers the effect of the section Class on the interaction between axial force and bending moment.
•20 tests of stainless steel SHS and RHS beam–columns were conducted.•Numerical model was created, validated and used for a numerical parametric study.•Based on the numerical data, existing design procedures were compared.•A new general stainless steel SHS/RHS beam–column design procedure was developed.
•Stressed-skin full scale test on steel monopitch portal frame was conducted.•Comparison of test data provided clear influence of the cladding on the horizontal structure stiffness.•FE numerical ...model was created, validated based on the test data.•The approach for taking into account the cladding horizontal shear stiffness was derived and compared.
This paper presents a study on the influence of sandwich panel roof cladding on the horizontal stiffness of load-bearing steel structures (stressed skin action). A full-scale test was carried out on a steel monopitch portal frame structure made in two stages – without (bare steel structure) and with roof sandwich panel cladding. Data obtained from both stages of the test are presented and are used to demonstrate the significant increase in horizontal stiffness caused by the cladding system. The test data were then used to validate an FE numerical model. A roof cladding made of composite panels is relatively stiff in its own plane. However, the critical detail is the connection of the panels to the sub-structure (e.g. purlins or rafters), i.e. the screw bearing capacity. Even within the serviceability limits, the internal sheet of the composite panel suffers a certain level of permanent bearing damage. Based on the test data, the results of the FE numerical model and the analytical approach for calculating the shear stiffness of the sandwich panels, the approach for taking into account the influence of the cladding on the horizontal stiffness was derived and compared. This approach is believed to be safe and simple for practical use, and it leads to load-bearing structure members with more slender cross-sections. In addition, the data and results that are obtained expand the limited amount of available data related to stressed skin action.
Behaviour of stainless steel slender members loaded by interaction of axial compressive force and bending moment is investigated in this research. Square hollow sections (SHS) made of austenitic ...stainless steel grade are considered. An initial numerical parametric study in FE software Abaqus is given and its results are compared to the existing design procedures and design standard rules. The investigated parameters are mainly the column slenderness, section slenderness, ratio between the applied bending moment and axial compressive force and the moment distribution along the member. The necessity of having additional design rules for stainless steels is firstly demonstrated on the values of interaction factors ky which are significantly higher for stainless steel members due to the material nonlinearity with decreased stiffness even at lower stress levels. As an alternative, the General Method is used for comparison to the Abaqus GMNIA model results. The limitation of the method when used for members of non-linear material behaviour is shown and a safe modification of design procedure is suggested.
Members loaded by the combination of compression and bending are very common structural elements. Behaviour of the carbon steel beam-columns was investigated in the past and based on the obtained ...data design procedures were derived. In the case of stainless steel beam-columns, the design procedures for carbon steel are not suitable due to significant material behaviour differences of both kinds of steel. In the last years many experimental and numerical studies were carried out to provide data from which some new approach describing stainless steel beam-column behaviour were derived. Unfortunately, each of the derived approaches exhibited some inaccuracies or limitations. Therefore, this thesis investigates the issue of stainless steel beam-columns with focus on the square and rectangular hollow cross-sections which are probably the most widely used cross-sections for stainless steel load-bearing structures. Presented research includes experimental study consisting of 20 conducted experiments of both square and rectangular hollow section members of two austenitic stainless steel grades, namely 1.4301 and 1.4404. In order to obtain greater amount of data, a numerical model was created in software Abaqus and validated on the experiments. It was used for a comprehensive numerical parametric study providing sufficient amount of data for an analytical part of the research. The aim of the research was to derive analytical approach for the stainless steel square and rectangular hollow section beam-column design. Data obtained from the numerical parametric study were used for this purpose. The conclusions of this research can broaden the knowledge of the investigated issue and contribute to the recent stainless steel design code.
There are several methods for considering the interaction between compression and bending for slender steel members. This is covered by the interaction formula and the general method, currently. For ...stainless steel, the structural design standards have been developed largely in-line and refer to carbon steel design guidelines. The current stainless steel interaction formula of axial force and bending moment given in EN 1993-1-4 was derived on limited results available. On the other hand, the general method may be used without any change for stainless steel according to the Eurocode despite the non-linear stress-strain behaviour, which obviously could lead to some drawbacks. Hence, the main objective of this paper is to compare the analysis results with existing Eurocode design formulas, the general method and some formula taken from experimental and parametric studies, showing their possible applicability, weaknesses and the need of further development. The conclusions are not applicable for stainless steel only, but they may be used for other non-linear materials such as aluminium alloys to some extent.
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