火灾作用下预应力连续梁桥的力学性能分析

发布时间：2018-01-04 06:00

本文关键词：火灾作用下预应力连续梁桥的力学性能分析　出处：《厦门大学学报(自然科学版)》2017年04期 　论文类型：期刊论文

【摘要】：为研究火灾对预应力连续梁桥力学性能的影响,以福建某受火连续箱梁桥为背景,参考桥梁火灾的现场资料,确定模型的边界条件,选取适当的混凝土、预应力筋本构模型,考虑混凝土及钢筋热工参数随温度的变化,通过对火灾时桥梁的瞬态温度场分析,得出温度随时间和空间的变化,并分别比较在自重作用下以及车道荷载作用下火灾前和火灾时桥梁的力学性能变化,研究火灾对桥梁中混凝土、预应力筋等材料的影响.结果表明,对大跨度桥梁结构来说,火灾后,结构的传热速度相对较慢,热量从受火面向非受火面逐渐扩散,温度呈平流状分布;火灾发生后,混凝土材料强度的损失要远远高于预应力筋强度的损失.
[Abstract]:In order to study the influence of fire on the mechanical properties of prestressed continuous girder bridge, taking a fire continuous box girder bridge in Fujian as background, referring to the field data of bridge fire, the boundary conditions of the model are determined and appropriate concrete is selected. In the constitutive model of prestressed tendons, considering the variation of thermal parameters of concrete and steel bar with temperature, the temperature changes with time and space are obtained by analyzing the transient temperature field of bridges during fire. The effects of fire on concrete and prestressed tendons in bridges were studied by comparing the mechanical properties of bridges before and during fire under deadweight and driveway loads respectively. The results show that the effects of fire on the concrete and prestressed tendons of bridges are studied. For the long-span bridge structure, the heat transfer rate of the structure is relatively slow after the fire, the heat gradually diffuses from the fire to the non-fire surface, and the temperature is an advection distribution. After fire, the loss of concrete strength is much higher than that of prestressed tendons.
【作者单位】：厦门大学建筑与土木工程学院;
【基金】：福建省自然科学基金青年创新项目(2016J05136)
【分类号】：U441
【正文快照】： 1桥梁概况和火灾背景1.1桥梁概况此桥位于福建某地,总长931m,为独立2幅双向6车道,上部结构为预应力钢筋砼连续箱梁,全桥共5联24跨,其桥跨组合为[(5×35.0)+(5×35.0)+(40.0+3×60.0+40.0)+(5×35.0)+(4×35.0)]m,桥宽组合为(2×11+4×0.5+2.0)m,设计荷载为公路I级,桥墩为实心

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