高铁站房型钢混凝土梁疲劳性能试验研究

Experimental study on fatigue behavior of steel reinforced concrete girders in high speed railway station

摘要:

鉴于型钢混凝土（SRC）梁在高铁站房应用的需要，对3根尺度和构造细节与实际工程一致的H型钢混凝土梁进行了基于设计荷载的静力试验和200万次的疲劳试验。在此基础上，继续进行了增大荷载幅的疲劳试验。介绍了SRC梁试件、加载和测试等方案以及试验结果，比较了静力加载和疲劳加载阶段的结构性能，阐述了SRC梁疲劳裂纹萌生和扩展的破坏特点。研究表明：在设计荷载静力作用和200万次循环作用下，SRC梁保持完好，处在弹性阶段，混凝土表面最大裂缝宽度不超过0.2mm；增大荷载幅之后，这些SRC梁又经历了31～146万次寿命后发生疲劳破坏；疲劳破坏之前，SRC梁各组件协同工作良好，应变分布符合平截面假定；疲劳破坏起源于H型钢受拉翼缘与腹板的焊接部位，焊接H型钢梁的疲劳性能对整个SRC梁的疲劳强度起着十分关键的作用。最后提出了改善SRC梁疲劳强度的建议和未来需进一步研究的工作。

Abstract:

For the needs of application of steel reinforced concrete (SRC) girders in high speed railway stations, both static and 2 million-cycle fatigue tests on three H-section steel reinforced concrete girders with the same dimension and constructional detail as that of a real engineering project were carried out under design loading. After that, further fatigue tests continued with higher loading than the design loading. The specimens, applied loading and testing program as well as experimental results are presented. The structural behavior under static and fatigue loading is compared. The failure feature of SRC girders about fatigue crack initiation and propagation is described. The current investigation indicated that the SRC girders kept in good condition and at the stage of elasticity when they were subjected to design static loading and 2 million-cycle fatigue loading. The concrete surface crack developed did not exceed 0.2 mm. Fatigue failure occurred after these girders were applied higher-level loading and endured from 0.31 to 1.46 million cycles. Before the fatigue failure, all components in the SRC girders were able to collaborate well and their strain distribution was in agreement with an assumption of plane cross section. The fatigue failure initiated from welded connection between a flange and a web in H-section steel. The fatigue behavior of the welded H-section steel beam played a key role in the fatigue strength of SRC girders. The suggestions for improving the fatigue strength of the SRC girders and future research work are recommended finally.