沪通铁路长江大桥主梁新细节疲劳性能试验研究

Experimental study on the girder's new detail fatigue performance of Hutong Railway Yangtze River Bridge

为了研究沪通铁路长江大桥主梁桁架斜腹杆过焊孔焊接细节的疲劳性能,根据相似理论设计了疲劳试验模型,并完成了3组(9个)试件的疲劳试验研究。试验中测得了各个试件在不同应力幅值下的疲劳寿命与应变状态;并建立试件的有限元模型对比分析试验结果。试验结果表明:疲劳试验中每个试件的裂纹扩展与破坏模式具有一致性;有限元计算结果与试验测试结果吻合良好,且误差均在15%以内;通过试验数据拟合得到过焊孔构造细节的S-N曲线,其斜率为1/2.66,与Eurocode3的71焊接细节S-N曲线存在一定的差异;失效概率为2.3%的200万次对应的该焊接细节疲劳应力幅值为37.89MPa。

To study fatigue performance of welded detail with cope hole in truss oblique rod of Hutong railway Yangtze River Bridge girder, the fatigue test models were designed based on the similarity theory. Three sets of specimens （ total 9 specimens） were tested under fatigue loading. The fatigue life and strain distribution of the specimens under fatigue loads with different stress amplitudes were measured. Meanwhile the finite element analysis of test specimens were carried out, and the FEA results were compared to the test results. The research results show that the crack propagation and failure modes of all specimens are coincident in the fatigue test. The FEA results agree well with the test results, and the tolerance is within 15%. The slope of the S-N curve regressed from the fatigue tests is 1/2.66, which is different from that of the category 71 welded detail in Eurocode3. The fatigue stress amplitude of this welded detail corresponding to the 2 million times with failure probability 2.3% is 37.89MPa.