黑瞎子岛乌苏大桥索梁锚固结构模型疲劳试验研究

Test Study of Fatigue of Cable-to-Girder Anchorage Structure Model of Wusu Bridge in Heixiazi Island

黑瞎子岛乌苏大桥主桥为(140+140)m独塔单索面大挑臂钢箱结合梁斜拉桥,该桥斜拉索与主梁之间采用钢锚箱式索梁锚固结构。为确保该索梁锚固结构在使用阶段的安全性,利用有限元软件ANSYS建立单节段钢箱梁模型,分析了设计索力下索梁锚固结构的应力分布;并制作足尺模型,采用疲劳累积损伤等效方法,结合该桥的设计交通流量和国外相关规范,按500kN疲劳荷载幅进行了足尺模型的疲劳性能试验研究。结果表明:在疲劳荷载作用下该索梁锚固结构的应力远小于规范允许值,结构的抗疲劳性能满足使用要求,结构具有良好的耐久性,且具有足够的安全储备。

The main bridge of the Wusu Bridge in Heixiazi Island is a long cantilever steel box composite girder cable-stayed bridge with a single pylon, a single cable plane and with span arrangement （140＋140） m. The stay cables and main girder of the bridge are connected, using the steel anchor box cable-to-girder anchorage structure. To ensure the safety of the structure at the service stage, the finite element software ANSYS was used to set up the model for the single block steel box girder and the stress distribution of the structure under the designed stay cable forces was analyzed. The full-scale model for the structure was fabricated as well and the test study of the fatigue performance of the model was carried out under the condition of 500 kN fa- tigue load amplitude, using the equivalent method of fatigue accumulative damage and with reference to the designed traffic flow of the bridge and the related foreign codes. The results of the test study indicate that under the action of the fatigue load, the stress of the structure is far less than the allowable values as specified in the codes, the fatigue resistance performance of the structure can satisfy the service requirements and the structure has good durability and sufficient safety margin.