In order to explore the effects of different parameters on the fire resistance of corrugated web prestressed U-type steel-concrete composite beams,a thermal-force coupling model of such composite beams at high temperatures was established,and the effects of geometrical parameters,such as the width and thickness of the upper concrete slab,and the wave height,wave angle,and flat section length of the corrugated steel web,on the fire resistance of composite beams were investigated.The results show that the critical state of the combined beam at high temperature is strength damage with the formation of plastic hinge.The larger the width of the concrete slab and the higher the slab thickness,the more obvi-ous the formation of inhomogeneous temperature field,which weakened the phenomenon of compressive stress concentra-tion and improved the high temperature bearing capacity of the combined beam.The corrugated steel web shear bending section bears the main shear force,the smaller the wave height,the weaker the heat-absorbing effect of the web concrete,the more obvious the buckling deformation of the steel web in the critical state.The wave angle is too large at high tem-peratures,the stronger the resistance of the steel web to out-of-plane deformation,but it will reduce the utilisation of the lower flange steel plate at high temperatures.The length of the flat section has no obvious influence on the heat-absorbing effect of the web concrete and the resistance of the steel web to out-of-plane deformation.After high temperature,the pre-stressing cable plays the main role of bending resistance,the larger the prestressing ratio is,the larger the bending stiff-ness of the combined beam is,and the smaller the deformation limit value of the combined beam is reached at high temper-ature,but the effect on the critical temperature is not obvious.
encased steel-concrete composite beamsfire resistanceupper concrete slabcorrugated steel websprestressing ratio
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