火灾环境下钢-混凝土组合梁力学性能试验研究

该文为研究组合梁桥在火灾环境下的基本力学性能与特征，制作具有代表性的3根缩尺梁模型:简支T形梁、简支箱形梁及连续箱形梁，利用火灾试验炉进行局部三面受火试验，并给出详细的试验方法。在试验过程中，分别观察组合梁常温下及火灾高温后的结构行为，量测火灾高温下组合梁的温度场，分析了结构的变形特点。通过对试验数据的深入分析与研究，可以发现火灾下钢-混凝土组合梁中钢梁为主要升温构件，且升温速度快，温度分布不均匀；混凝土顶板具有一定的吸热作用，但不应忽略其对钢梁升温及温度分布的影响；从实测变形看，钢-混凝土组合连续梁体系的抗火性能要优于简支梁体系。研究成果可以为组合梁桥防火灾设计与分析提供试验依据与理论参考。

EXPERIMENTAL STUDY ON MECHANICAL PERFORMANCE OF STEEL-CONCRETE GIRDERS UNDER FIRE LOADING

The mechanical performance of steel-concrete girder structure under fire loading was investigated in the present study. Three typical scale models: a simply supported T-shape girder, a simply supported box girder and a continuous box girder, were manufactured. Fire loading was then applied on three sides of the girders in a fire experimental oven. The behavior of the these girders under normal condition and fire loading was observed. The thermal distribution and structural deformation of the three girders were also measured. Results show that thermal energy mainly concentrates in the steel girder in the composite structure, and the temperature rises fast in a non-homogeneous pattern. Concrete slabs absorb the heat energy to a certain extent, and their influence on temperature rising and thermal distribution of steel girders cannot be neglected. From deformation measurement, it is seen that continuous steel-concrete girders have a better anti-fire performance than simply-supported girders. Outcomes from the current study are expected to provide experimental guidance and theoretical reference for ati-fire design and analysis of steel-concrete girders.