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大连星海湾大桥是中国首座双层钢桁架公路悬索桥,其主桁架杆件采用整体节点连接。为了掌握该桥整体节点的疲劳性能,对弦杆整体节点1∶2缩尺模型进行疲劳试验。参考国内外同类桥梁疲劳试验,采用英国规范BS 5400规定的标准疲劳车,确定疲劳试验荷载取值。在设定的试验荷载下进行200万次循环加载。在试验过程中每50万次循环加载后停机进行静载试验,并对模型重点部位进行裂纹观察。结合国内外相关规范,评估整体节点的疲劳安全性能。试验结果表明:实测应力幅基本为50 MPa以下,试验模型应力水平较低,疲劳加载200万次后,试验模型未出现裂纹。在结构使用寿命期间内和正常养护维修情况下,整体节点不会发生疲劳破坏。
Dalian Xinghai Bay Bridge is China’s first double-deck steel truss highway suspension bridge, the main truss member with the overall node connection. In order to grasp the fatigue performance of the bridge as a whole, the fatigue test was carried out on the 1: 2 scale model of the chord integral node. Reference to similar domestic and foreign bridge fatigue test, using the British standard BS 5400 standard fatigue truck, to determine the value of fatigue test load. 2 million cycles of loading at the set test load. In the course of the test every 500,000 cycles after the shutdown load static load test, and crack the key parts of the model observation. Combined with relevant norms at home and abroad, evaluate the fatigue safety performance of the whole node. The test results show that the measured stress amplitude is basically below 50 MPa, the stress level of the test model is low, and no crack occurs in the test model after 2 million fatigue loads. In the service life of the structure and maintenance of normal maintenance, the overall node will not fatigue damage occurs.