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With the growing use of stainless steel in the construction and offshore industries, there is an increasing interest and need to study the performance of stainless structures at elevated temperatures. The behavior and design of stainless steel I-section beam-columns in fire is investigated in this paper, addressing a scarcity of previous research on this topic. Finite element (FE) models of stainless steel beam-columns, able to replicate their response at elevated temperatures, are created and validated; the validated models are then used to perform parametric studies to generate extensive benchmark structural performance data. The design rules set out in the European structural steel fire design standard EN 1993-1-2 are assessed and shown to provide rather inaccurate and often unsafe ultimate strength predictions for stainless steel I-section beam-columns in fire. New fire design rules for stainless steel beam-columns are put forward. It is shown that the new proposals are able to offer improved accuracy and design efficiency relative to the EN 1993-1-2 beam-column design rules. The reliability of the proposed design rules is also verified on the basis of the fire design reliability criteria set out by Kruppa [Eurocodes–Fire parts: Proposal for a methodology to check the accuracy of assessment methods, CEN TC 250, Horizontal Group Fire, Document no: 99/130 (1999)], thereby demonstrating the suitability of the proposed design rules for inclusion in the upcoming revised version of EN 1993-1-2. [ABSTRACT FROM AUTHOR]

The importance of allowing for the many different types of structural interaction that have an effect on the performance of light gauge members when used in practical situations is emphasized. A distinction is drawn between internal interactions involving the various plate elements of the steel profiles and external interactions involving the other components in the system. Although full-scale testing of representative systems can capture this behavior, the costs involved make this an impractical general basis for design; codified methods generally consider only isolated plates within members and isolated members within systems, thereby neglecting the potentially beneficial effects of both forms of interaction. Properly used, modern methods of numerical analysis offer the potential to systematically allow for both forms of interaction — provided the numerical models used have been adequately validated against suitable tests. The use of such an approach is explained and illustrated for three commonly used structural systems: roof purlins, floor beams, and columns in stud walls. In each case, it is shown that, provided sufficient care is taken, the numerical approach can yield accurate predictions of the observed test behavior. The subsequently generated large portfolio of numerical results can then provide clear insights into the exact nature of the various interactions and, thus, form the basis for more realistic design approaches that are both more accurate in their predictions and which lead to more economic designs. Building on this, modifying existing arrangements so as to yield superior performance through specific modifications is now possible. Two such examples, one in which improved interconnection between the components in a system is investigated and a second in which prestressing is shown to provide substantial enhancement for relatively small and simple changes, are presented. [ABSTRACT FROM AUTHOR]

Steel-reinforced concrete-filled stainless steel tubular (SRCFSST) columns combine the advantages of concrete-filled stainless steel tubular (CFSST) columns and steel-reinforced concrete (SRC) columns, resulting in excellent corrosion resistance, good economy, good ductility, and excellent fire resistance. Thus, SRCFSST columns have many potential structural engineering applications, especially in offshore structures. The performance of SRCFSST columns at elevated temperatures is investigated by finite element (FE) analysis in this paper. Firstly, FE models capable of capturing the full load-deformation response of structural members at elevated temperatures are developed and validated against relevant published tests on CFSST and SRC columns under fire conditions. Based on the validated FE models, the behavioral mechanisms of the SRCFSST columns under fire are explained by analysis of the sectional temperature distribution, typical failure modes, axial deformation versus time response, and load redistribution. Finally, the fire resistance of SRCFSST columns is evaluated in comparison to CFSST columns with equivalent sectional load-bearing capacity at ambient temperature or equivalent steel ratios. The results lay the foundation for the development of fire resistance design rules for SRCFSST columns. [ABSTRACT FROM AUTHOR]

An experimental investigation has been conducted into the degree of shear interaction between cold-formed steel floor joists and wood-based flooring panels and the resulting benefits derived in terms of composite action. A series of four-point bending tests have been carried out to evaluate the overall system behavior, while material tests have been performed to accurately define the material properties of each component of the examined system. Two different shear transfer mechanisms were examined: self-drilling screws with varying spacing and structural adhesive. The bare system was also tested to provide a reference response, against which the stiffness and capacity of the composite system could be bench-marked. The experiments showed that significant benefit could be derived as a result of composite action with as much as a 100% increase in bending capacity and 42% increase in stiffness. [ABSTRACT FROM AUTHOR]

The present generation of international structural steel design codes treats material nonlinearity through simplified elastic-plastic or rigid-plastic material models. However, the actual stress-strain response of structural steel is more complex than this and features, in particular, strain hardening. Strain hardening refers to the increase in strength beyond yield because of plastic deformation. The influence of strain hardening on the behavior and design of steel structures is examined in this study through both the experimentation and the analysis of existing data, and a method to exploit the additional capacity that arises is outlined. Both determinate and indeterminate structures are considered. The proposed design method, referred to as the continuous strength method (CSM), is a deformation-based design approach employing a continuous relationship between cross-sectional slenderness and cross-sectional deformation capacity, together with a material model that allows for strain hardening. Comparisons are made between test results generated as part of the present study and collected from existing studies, and the predictions from the CSM and Eurocode 3 (EC3). For all cases considered, the CSM, through a rational exploitation of strain hardening, offers a more accurate prediction of observed physical behavior. [ABSTRACT FROM AUTHOR]