组合桥面板疲劳荷载后剩余承载力试验研究

Residual Static Load Bearing Capacity of Orthotropic Composite Bridge Deck After Fatigue Loading

为了研究高性能混凝土组合桥面板经历疲劳荷载后的剩余承载力,设计制作了两个足尺的正交异性高性能混凝土组合桥面板,通过疲劳和静力加载试验测试了正交异性组合桥面板的静力承载能力、破坏形态与疲劳后剩余极限承载力。试验结果表明:正交异性高性能混凝土组合桥面板经历疲劳荷载后的静力破坏形态为受弯破坏,试件达到极限状态时中支点截面U肋屈曲,受拉钢筋屈服,负弯矩区混凝土板开裂严重,组合桥面板的受力性能发生退化。经过疲劳加载后的桥面板的剩余极限承载力较没有经过疲劳加载的桥面板承载力下降了约11.6%。基于钢筋混凝土黏结滑移理论推导了适用于疲劳荷载作用后的高性能混凝土组合桥面板平均裂缝间距计算公式。对比试验结果,所提出的平均裂缝间距计算公式具有良好的精度,可为实际工程应用提供理论参考。

The ultimate bending capacity of two full-scale steel-concrete composite bridge decks were tested to study the residual bearing capacity of the high-performance concrete composite bridge deck after fatigue loading.A full-scale static-loading test was carried out for researching the static behavior of the orthotropic composite bridge deck,including the strain of concrete and steel bars,the deformation of the structure and the development of cracks.The test results prove the failure mode of the orthotropic composite deck to be a flexural failure.When the ultimate strength on the specimen reaches,the U-rib of the middle fulcrum section is buckling,and the tensile steel bars are yielding.The concrete in the negative bending moment area is seriously cracked,and the specimen has obvious deformation.Meanwhile,a flexural failure also appears on another bridge deck specimen after fatigue loading,and the residual bearing capacity decreases by about 11.6%in comparison with the specimen without fatigue loading.Based on the bond-slip theory of reinforced concrete,a formula for calculating the average crack spacing of orthotropic composite bridge decks after fatigue loading is deduced.Compared with the test results,the proposed formula for calculating the average crack spacing has good accuracy,and the relevant research results can provide theoretical reference for practical engineering applications.