正交异性钢桥面板纵肋腹板与面板连接构造的疲劳试验研究

Fatigue Test Study on the Joint Structure between the Deck and Longitudinal Rib Web of Orthotropic Steel Bridge Deck

针对正交异性钢桥面板的纵肋腹板与面板连接构造易出现疲劳裂纹的问题,通过不同纵肋腹板与面板厚度配合及制造工艺共5组48个连接构造试件的疲劳试验,研究正交异性钢桥面板纵肋腹板与面板连接构造的疲劳性能及疲劳设计S-N曲线。研究结果表明:当12mm厚的面板搭配8mm厚的纵肋腹板时,试件发生沿面板厚度方向的剪切破坏,疲劳性能较差;当面板厚度从14mm增至16mm时,试件的疲劳性能有所提高;当面板厚度从16mm增至18mm、纵肋腹板厚度从8mm增至9mm时,试件的疲劳性能基本无改变;双侧熔透焊对疲劳试件的疲劳性能无改善,反而略低于单侧熔透75%焊。对连接构造试件的疲劳试验数据进行S-N曲线回归分析表明,连接构造可归为铁路桥梁钢结构设计规范中的IX类构造,当破坏循环次数为2×106时,其应力幅为71.9MPa。

The joint structure between the deck and longitudinal rib web of orthotropic steel bridge deck is liable to have fatigue cracks.Therefore,fatigue tests are carried out on 48 test specimens of 5 groups with different longitudinal rib web and deck thickness as well as manufacturing technology to study the fatigue performance and fatigue design S-N curve of the joint structure.The results show that： when the thickness of longitudinal rib web is 8 mm and deck thickness is 12 mm,shear failure will occur along the thickness direction of the deck and fatigue performance is poor;when the deck thickness is increased from 14 to 16 mm,the fatigue performances of test specimens have been somewhat improved;when the deck thickness is increased from 16 to 18 mm,the thickness of longitudinal rib web is increased from 8 to 9 mm,the fatigue performances of test specimens have hardly changed;the fatigue performances of test specimens have not been improved at all by bilateral penetration welding,instead,slightly lower than 75% unilateral penetration welding.S-N curve regression analysis on the fatigue test data of joint structure shows that the joint structure can be classified into IX category in code for design of steel structures in railway bridge.When failure cycle is 2×106,the stress amplitude is 71.9 MPa.