钢-薄层UHPC轻型组合桥面结构疲劳性能研究

Studies on Fatigue Performance of the Steel-thin UHPC Lightweight Composite Bridge Deck Structure

以含U型肋的钢-薄层超高性能混凝土(UHPC)轻型组合桥面结构为对象,开展了稀疏栓钉布置下的组合桥面三点弯曲疲劳试验,研究了栓钉抗剪和薄层UHPC抗弯拉、疲劳性能,并进行了剩余强度试验。疲劳试验结果表明,累计经历3200万次疲劳加载后,UHPC顶面的最大裂缝宽度仅为0.05 mm,且钢-薄层UHPC界面未见显著滑移。剩余强度试验表明,UHPC的名义开裂应力为15.7 MPa,相较于未经历疲劳试验的类似试件应力降低了38.9%。此外,试件的最终破坏形态为U肋底部屈曲。

Taking the U-ribbed steel-UHPC(ultra-high performance concrete) lightweight composite bridge deck as the researched object,a three point bending fatigue test of composite bridge deck was carried out under sparse stud layout.The shear resistance of stud,bending tension of thin layer and fatigue performance were studied and the residual strength was tested.The test result shows that after the accumulated fatigue loading of 32 million times,the maximum crack width in UHPC was only 0.05 mm and no obvious slips were observed at the steel-UHPC interface.The residual strength test indicates that the nominal cracking strength of UHPC was 15.7 MPa,which is 38.9% lower than that of similar test pieces without fatigue experience.In addition,the final failure pattern of the specimen was bottom flection of the U rib.