中文摘要：

为揭示多梁式混凝土T型梁桥的整体抗火性能，利用热-力耦合方法对5片混凝土T型梁桥火灾场形变和主拉应力进行了分析，研究了变区域桥面受火模式，分析了相对应各片梁跨中和两侧四分点断面横桥向挠度在延火前后期自重荷载作用下的空间变化规律及主拉应力分布规律。研究结果表明：桥面整跨火灾下多梁式混凝土T型梁桥梁肋反拱值较其他区域火灾下梁肋反拱值大，延火后期跨中边中肋挠差为四分点边中肋挠差的1．5倍，中肋呈余弦状波浪形；部分区域火灾下，近火源区域关键截面的边中肋挠差较远火源区域的边中肋挠差大，其最大比值可达4．0倍；不同火源区域模式下，延火后期跨中挠度始终保持挠度最大值；随延火时间的增加，混凝土T型梁桥在火荷栽作用下顶板主拉应力由点条状分布状态逐渐交替发展，最终主拉应力区出现在梁肋下缘。

英文摘要：

In order to find out the whole fire-resistant performance of multi-beam T-shape girder bridge, thermo-mechanics coupled method was applied to analyze the deformation of five T- shaped girder bridge and main tensile stress. Multi-range of deck fire was studied. Mid-span transverse deflection of each beam during prior period and anaphase of extending-fire time was an- alyzed under condition of dead load. The results indicate that deflection of mid-span and the quar- ter span is bigger under the condition of the whole span fire than that under the condition of other part fire; the ratio of deflection difference between the middle span and the quarter span is 1.5; the middle rib presents a consine and wave shape. Deflection difference near fire part is much big- ger than that far from fire part under the condition of part fire, in which the biggest ratio is 4.0 ; the mid-span deflection stands in the peak position under condition of all kinds of fire models; with the increase of fire time, the main tensile stress in the upper floor of multi-beam concrete T-shaped girder bridge changes from dot and stripe distribution to gradual alternate development untill the main stress appears in the bottom of beam body. 2 tabs, 5 figs, 9 refs.