Numerical analysis of stainless steel beam-columns in case of fire (original) (raw)

Buckling of stainless steel columns and beams in fire

Engineering Structures, 2007

Material properties and their response to elevated temperatures form an essential part of structural fire design. At elevated temperatures, stainless steel displays superior material strength and stiffness retention in comparison to structural carbon steel. Although independently important, the relationship between strength and stiffness at elevated temperature also has a significant influence on the buckling response of structural components. This paper examines existing test results and presents the results of a numerical parametric study, using ABAQUS on stainless steel columns in fire. Sensitivity to local and global initial geometric imperfections, enhancement of corner strength due to cold-work and partial protection of the column ends is assessed. Parametric studies to explore the influence of variation in local crosssection slenderness, global member slenderness and load level are described. Test results are compared with the current design rules in Eurocode 3: Part 1.2, the Euro Inox/ SCI Design Manual for Structural Stainless Steel and those proposed by CTICM/ CSM. The results of a total of 23 column buckling fire tests, 6 stub column fire tests and 6 fire tests on beams have been analysed. Overly conservative results and inconsistencies in the treatment of buckling phenomena and the choice of deformation limits are highlighted. A revised buckling curve for stainless steel in fire, consistent strain limits and a new approach to cross-section classification and the treatment of local buckling are proposed. These revisions have led to a more efficient and consistent treatment of buckling of stainless steel columns and beams in fire. Improvements of 6% for column buckling resistance, 28% for stub column (crosssection) resistance and 14% for in-plane bending resistance over the current Eurocode methods are achieved.

Stainless steel beam-columns in case of fire

2007

Eurocode 3 states that stainless steel structural members, subjected to high temperatures, must be designed with the same expressions used on carbon steel members. However, as these two materials have different constitutive laws, it should be expected that different formulae for the calculation of member stability should be used for room temperature design. In a recent work, the authors have proposed a more accurate procedure for the evaluation of the fire resistance of stainless steel columns which necessarily affects the beam-column design formulae. This work presents a numerical study of the behaviour of stainless steel beam-columns subjected to fire.

Axially Loaded Stainless Steel Columns in Case of Fire

Journal of Structural Fire Engineering, 2010

The simple model of Eurocode 3, for the fire resistance evaluation of stainless steel members, are based on the procedures used for carbon steel structural elements. However, due to the existing differences in the constitutive laws of these two materials, it is expected that it would not be possible to use, in both materials, the same formulae for the member stability calculation, as proposed in Eurocode 3. This paper aims at increasing the knowledge on the behaviour of stainless steel axially loaded columns at elevated temperatures. For this purpose, a geometrical and material non linear computer code has been used to determine the buckling load of these elements. The Eurocode formulae are evaluated and a new proposal, that ensures accurate and conservative results when compared with the numerical simulations, is presented. 1

Duplex stainless steel columns and beam-columns in case of fire

2008

It is the purpose of this paper to evaluate the accuracy and safety of the currently prescribed design rules in Eurocode 3: Part 1.2 for the evaluation of the resistance of duplex stainless steel columns and beam-columns. This evaluation is carried out by performing numerical simulations on Class1 and Class 2 stainless steel H-columns. These numerical simulations are performed using the program SAFIR. Eurocode 3 states that stainless steel structural members, subjected to high temperatures, must be designed with the same formulae used for carbon steel members. However, as these two materials have different constitutive laws, it should be expected that, different formulae for the calculation of member stability should be used for fire design. It is considered buckling in the two main cross-section axis, and, in the case of the beam-columns, different bending moment diagrams. Parametric studies of the behaviour of the duplex EN 1.4462 stainless steel grade (austenitic-ferritic in Euro...

Lateral-torsional buckling of ferritic stainless steel beams in case of fire

WIT transactions on engineering sciences, 2007

This work presents a numerical study of the behaviour of ferritic stainless steel I-beams subjected to lateral-torsional buckling and compares the obtained results with the beam design curves of Eurocode 3. New formulae, for the lateral-torsional buckling, that approximate better the real behaviour of ferritic stainless steel structural elements in case of fire are proposed. These new formulae were based on numerical simulations using the program SAFIR, which was modified to take into account the material properties of the stainless steel.

Structural fire performance of axially and rotationally restrained stainless steel columns

Thin-Walled Structures, 2019

This paper describes a step improvement in the numerical modelling of the structural response of axially and rotationally restrained stainless steel columns at elevated temperatures. The developed finite element models form a sequentially coupled thermal stress analysis that comprises a heat transfer model, a buckling analysis, and a geometrically and materially non-linear stress analysis. The proposed finite element methodology is more sophisticated than any other reported attempts to model the fire response of structural stainless steel that take into account influence of adjoining members. A high degree of predictive accuracy is achieved, with the developed models on average predicting the failure temperatures and times of test specimens reported in the literature within 2% and 6%, respectively. A parametric study is performed that investigates the influence of axial restraint stiffness, rotational restraint stiffness, column slenderness and load level. It is shown that while increasing axial restraint stiffness reduces the failure temperature of stainless steel columns in fire, increasing rotational restraint stiffness has the opposite effect. The methodology and results of this paper will provide both a tool for practice and a suite of results that can be extended to develop the existing and currently limited codified approaches to structural stainless steel design.

Numerical study of fire resistance of stainless steel circular hollow section columns

Journal of Fire Sciences, 2020

Stainless steel has countless desirable characteristics for a structural material. Although initially more expensive than conventional carbon steel, stainless steel structures can be competitive due to their smaller need for fire protection material and lower life-cycle cost, thus contributing to a more sustainable construction. The most common stainless steel groups used in structural applications are the austenitic, ferritic and austenitic-ferritic (also known as Duplex grades). This work presents a numerical study on the behaviour of stainless steel circular hollow section members under axial compression at elevated temperatures, with different cross-section slenderness. The numerically obtained ultimate load-bearing capacities are compared with simplified calculation formulae from Eurocode 3 for columns under fire situation. A parametric study, considering different stainless steel grades from the aforementioned groups, cross-sectional classes and slendernesses, is here presented for different elevated temperatures. The numerical analyses were performed with the finite element programme SAFIR, with material and geometric non-linear analysis considering imperfections. Comparisons between the numerical results and the Eurocode 3 rules demonstrated that a specific design approach must be developed for stainless steel columns under fire situation.