Parametric Analysis for Fire Resistance of Composite Steel-Concrete Beams with Corrugated Webs Accounting

Steel-concrete composite beams with corrugated webs have higher bearing capacity than traditional composite beams.In this paper, ABAQUS finite element method is used to established the corrugated web under the high temperature thermal-mechanical coupling model.The influence of load ratio, span-height ratio, web wave angle, corner constraint ratio and axial constraint ratio on the fire resistance of composite beams is studied by analyzing the mid-span deflection and the variation curve of axial force at beam end with temperature of corrugated web composite beams.The results show that neutral axis of composite beams with corrugated webs moves up continuously along section height and finally forms the plastic hinge and reaches the critical state when exposed to fire. Without rotation and axial restraints, the load ratio has a greater impact on the fire resistance of steel-concrete composite beams with corrugated webs; as the load ratio increases, the critical temperature of the composite beam also decreases; under high temperature, the span-to-height ratio increases. The smaller, the deflection value of the composite beam in the critical state is smaller; under other conditions being the same, the larger the web wave angle is, the closer it is to a flat web composite beam, the more likely it is that local instability will occur, and the fire resistance will be worse. After considering the beam rotation and axial restraints, the critical temperature of the composite beam is higher under the same load ratio, which is about 1.2 to 1.5 times the critical temperature of the unconstrained composite beam. When the critical state is reached, the deflection is smaller, about 0.6 to 0.8. When the corner constraint is large, The larger the corner restraint ratio of corrugated web composite beams, the slower the rate of mid-span deflection decrease, the greater the negative bending moment at the beam end, and the more prone the lower flange of the beam end to buckling failure under compression. When the wave angle of the web is 65, the mid-span deflection of the composite beam with non-end restraint corrugated web decreases fastest, while the composite beam with end restraint corrugated web has the largest deflection when the wave angle of the web is 45.