Structural steel

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Effect of High Temperature Creep on the Fire Response of Restrained Steel Beams

Journal Title, Volume, Page: 
Materials & Structures Journal, 43(10), pp.1327-1341.
Year of Publication: 
2010
Authors: 
V. K. R. Kodur
Department of Civil and Environmental Engineering, 3546 Engineering Building, Michigan State University, East Lansing, MI 48824-1226, United States
M.M.S. Dwaikat
Department of Civil and Environmental Engineering, 3546 Engineering Building, Michigan State University, East Lansing, MI 48824-1226, United States
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Palestine
Preferred Abstract (Original): 
At room temperature, and at service load levels, creep has little effect on the performance of steel structures. However, under fire conditions, creep becomes a dominant factor and influences fire resistance of steel members. Under fire conditions, significant forces develop in restrained steel beams and these forces induce high stresses in the steel section. The extent of creep deformations is affected by magnitude and rate of development of stress and temperature in steel. In this paper, the effect of high temperature creep on fire response of restrained beams is investigated. Current high temperature creep models are compared. Finite element model created in ANSYS was validated by comparing the predictions with fire test data. The validated model was applied to investigate the effect of load level, heating rate, fire scenario and fire induced axial restraint on the extent of creep deformations. Results from the parametric study indicate that the influence of high temperature creep increases with the increase in axial restraint, heating rate, and load level. Generally, neglecting high-temperature creep effect stiffens the structural response and leads to reduced deflections but larger restraint forces. Therefore, neglecting high temperature creep in fire resistance analysis of steel structures can lead to unconservative predictions.
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High-Temperature Properties of Steel for Fire Resistance Modelling of Structures

Journal Title, Volume, Page: 
Journal of Materials in Civil Engineering, ASCE, 22(5), 423-434
Year of Publication: 
2010
Authors: 
Venkatesh Kodur
Civil and Environmental Engineering, Michigan State Univ., East Lansing, MI (corresponding author)
M.M.S. Dwaikat
Civil and Environmental Engineering, Michigan State Univ., East Lansing, MI
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Palestine
R. Fike
Civil and Environmental Engineering, Michigan State Univ., East Lansing, MI
Preferred Abstract (Original): 
Fire is one of the most severe conditions to which structures can be subjected, and hence, the provision of appropriate fire safety measures for structural members is an important aspect of design. The recent introduction of performance-based codes has increased the use of computer-based models for fire resistance assessment. For evaluating the fire resistance of steel structures, high-temperature properties of steel are to be specified as input data. This paper reviews high-temperature constitutive relationships for steel currently available in American and European standards, and highlights the variation between these relationships through comparison with published experimental results. The effect of various constitutive models on overall fire resistance predictions is illustrated through case studies. It is also shown that high-temperature creep, which is not often included in constitutive models, has a significant influence on the fire response of steel structures. Results from the case studies are used to draw recommendations on the use of appropriate constitutive models for fire resistance assessment. Read More: http://ascelibrary.org/action/showAbstract?page=423&volume=22&issue=5&jo...
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