整体桥面结构连接细部模型双向受拉疲劳试验研究

Fatigue Test Study of Model for Connection Detail of Integral Deck Structure Subjected to Two-Way Tensioning

南京大胜关长江大桥主桥为六跨连续钢桁拱桥,采用整体桥面板结构。制作钢桥面板和主桁下弦杆节点板连接细节足尺模型,分3个阶段进行疲劳试验。每个阶段疲劳试验完成后,以该阶段试验荷载上限进行静力试验。ANSYS分析结果显示,模型设计及加载满足模拟要求,试验加载能够反映实际结构的受力状况。静力试验结果表明,各级荷载作用下模型均处于弹性阶段,卸载后基本没有残余应力。疲劳试验结果表明,在各加载循环次数下试验时,没有产生因为疲劳损伤影响应力重分布的现象;按给定的计算应力幅加载作用下,常幅加载寿命大于200万次;疲劳抗力大于试验设计荷载作用下的双向应力幅;连接细部具有足够的抗疲劳能力。

The main bridge of Dashengguan Changjiang River Bridge in Nanjing is a six-span continuous steel truss arch bridge and the deck of the bridge makes use of the integral steel deck structure. The full-scale model for the connection detail between the deck and gusset plates of the bottom chord of the main truss is fabricated and the fatigue tests for the model are made in three stages. After the fatigue test in each stage is completed, the upper limit of the test load in that stage is used to continue to make the static load test. The analysis of the ANSYS shows that the design and loading of the model can meet the requirements for simulation and the loading applied in the tests can represent the force conditions of the actual structure. The static load test shows that under the action of different loading levels, the model is still in the state of elasticity and is almost without residual stress after unloading. The results of the fatigue tests further show that when the model was tested under different times of load cycling and the stress redistribution due to the fatigue damage influence does not occur. Under the action of loading according to the given calculated stress amplitude, the life of the model under constant stress amplitude loading is longer than 200× 10^4 times of load cycling, the fatigue resistance is greater than the two-way stress amplitude of the designed test＇ load and the connection detail between the deck and gusset plates has sufficient fatigue resistance capacity.