Inelastic Strength for Fire Resistance of Composite I-Beam Covered by Insulation Material Subjected to Basic Loading Condition

• Published in: Metals (Basel ) Vol. 11; no. 5; p. 739
• Main Authors: Nguyen, Xuan Tung, Park, Jong Sup
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.05.2021
• Subjects: composite beam; Composite beams; Concrete; Concrete slabs; Degradation; Finite element analysis; Finite element method; fire; Fire codes; fire insulation; Fire resistance; Heat transfer; High temperature; I beams; inelastic strength; Insulation; Load; Low temperature; Material properties; nonlinear analysis; Numerical analysis; Reinforced concrete; Simulation; Steel beams; Temperature dependence; Temperature distribution; Thickness; Yield stress
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met11050739

This paper presents a nonlinear numerical study on the moment resistance of composite steel-concrete beam using fire insulation subjected to various fire scenarios and basic loading conditions. The temperature-dependent material properties of fire insulation, concrete and steel were taken into consideration. The nonlinear finite element analysis was done by utilizing a commercial finite element program, ABAQUS. The obtained moment capacity of the composite I-beam from the current fire code was also performed and compared. The results showed that the fire scenarios and the fire insulation thickness have a great influence on the temperature distribution and strength degradation of the composite beam. The capacity of the beam in hydrocarbon fires, which is the most severe scenario, decreases faster than that in ISO834 standard fire and external fire. The fire resistance of the beam increases as the fire insulation thickness increases due to the temperature degradation in the steel beam. The calculated results from the current fire codes give conservative value at normal temperature and low temperature. The current fire codes can give unconservative values at high temperature when there is a great temperature discrepancy between parts of the beam. A new factor was proposed to determine the fire moment resistance of the composite beam with non-uniform temperature.