火灾作用下预应力连续梁桥的力学性能分析

(厦门大学建筑与土木工程学院,福建 厦门 361005)

连续梁桥; 预应力; 火灾; 温度场; 应力场

Mechanical Performance Analysis of Pre-stressed Continuous Beam Bridge Under Fire
SHAO Wenjun,SONG Yu*

(School of Architecture and Civil Engineering,Xiamen University,Xiamen 361005,China)

continuous beam bridge; pre-stress; fire; temperature field; stress field

DOI: 10.6043/j.issn.0438-0479.201612005

备注

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.

For the purpose of studying the effect of fire on mechanical properties of pre-stressed concrete continuous girder bridges,the boundary condition of the model is imposed by referring to data and results of the bridge fire.Constitutive models of the concrete and pre-stressed tendons are adopted and analyzed.Meanwhile,thermal parameters of the concrete and steel bars are also considered.Through the analysis of the transient temperature range of the bridge in the fire,changes of temperature according to time and space are obtained respectively.The mechanical performance of the bridge in normal temperature and fire temperature are also compared under the action of weight and lane loads,concrete,pre-stress tendons and so forth.In this paper,we have analyzed the influence of the fire on the material,and the influence of the temperature field on the stress range of the bridge is obtained.This analysis model can be used as a reference for the reparation,reinforcement,and fire resistance of the bridge.