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为研究公路火灾对大跨径悬索桥带来的影响,弥补悬索桥火灾研究的空白,结合结构火灾分析的特点,确定选择间接耦合法进行热—结构耦合分析。以300 MW车辆火灾为例,运用ANSYS有限元程序,建立了悬索桥不同断面的火灾坐标模型,在总结国内外火灾研究工作的基础上,基于Ingason H.平方增长模型,以典型的大跨径悬索桥缆索承重构件的公路火灾安全距离为研究对象,以降低工程风险、保证大跨径悬索桥结构的安全性和稳定性为研究目标,对大跨径悬索桥吊索和主缆安全距离进行数值模拟,提出了适用于公路火灾研究的热释放率数学模型;建立了公路火灾的物理模型并确定了公路火灾燃烧热源的尺寸和单位面积释热率;并通过热—结构耦合分析,确定了公路火灾下悬索桥吊索和0.4~1.0 m范围内不同直径主缆的安全距离。研究成果可为今后大跨径悬索桥的抗火设计提供科学依据。
In order to study the influence of road fire on long-span suspension bridges and to make up for the blank of the study on fires of suspension bridges, the thermo-structural coupling analysis based on structural fire analysis was established. Taking 300 MW vehicle fire as an example, the fire coordinate model of different sections of suspension bridge was established by ANSYS finite element program. On the basis of summarizing domestic and international fire research work, based on Ingason H. squared growth model, a typical long-span suspension bridge The safety distance of highway fire load carrying members is taken as the research object. In order to reduce the project risk and ensure the safety and stability of the long-span suspension bridge, the safety distance between the slings and main cables of the long-span suspension bridge is numerically simulated. A mathematical model of heat release rate suitable for highway fire research was established. The physical model of highway fire was established and the size of heat source and the heat release rate per unit area of road fire were determined. By means of thermo-structure coupling analysis, the suspension bridge Slings and 0.4 ~ 1.0 m range of different diameters of the main cable safety distance. The research results can provide a scientific basis for the fire resistance design of long-span suspension bridges in the future.