Fire Resistance and Design of Composite Box Girder with Corrugated Steel Webs and Steel Bottom Plate
Research purposes:In recent years,the increase in traffic volume has raised concerns about bridge fires resulting from vehicle collisions or the transportation of flammable materials.To understand the fire response of composite box girder with corrugated steel webs and steel bottom plate,a three-dimensional thermal-mechanical coupling analysis model was developed using ANSYS.This model analyzed the temperature field distribution and the decay of flexural bearing capacity under fire conditions.Additionally,it examined the impact of various fire scenarios on the fire resistance limit of the composite box girder and proposed fire-resistant design methods.Research conclusions:(1)The flexural bearing capacity of composite box girders under fire conditions progresses through three stages.The mid-span deflection,across various fire lengths,develops in two stages over time.As the fire length increases,the deflection growth rate of the composite box girder becomes more significant,with a more pronounced thermal bending effect during the initial fire stage.(2)Using the deflection failure criterion to determine the fire resistance limit of composite box girders is safer than using the resistance criterion.(3)Adding various types of stiffeners to the bottom plate of composite box girders improves their fire resistance limit.With the same amount of stiffener material,local stiffeners on the bottom plate enhance the fire resistance limit more effectively than continuous stiffeners.(4)The research findings can provide a reference for the theoretical analysis and fire-resistant design of composite box girder with corrugated steel webs and steel bottom plate.
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