Dynamic response of cable breakage in double-tower cable-stayed bridge with steel truss girder(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2017年06期
- Page:
- 70-77
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Dynamic response of cable breakage in double-tower cable-stayed bridge with steel truss girder
- Author(s):
- ZHENG Xiao-bo; ZHANG Gang; SONG Yi-fan
- School of Highway, Chang’an University, Xi’an 710064, Shaanxi, China
- Keywords:
- bridge engineering; cable-stayed bridge; reverse load; cable breakage; dynamic response; amplification of load
- PACS:
- U448.27
- DOI:
- -
- Abstract:
- For the problem that failure of cables in the process of using may lead to a serious decline in bearing capacity of cable-stayed bridges, this paper proposed a reverse loading method to simulate the effect of cable breakage. Through simulating the time of cable damage and incentive to the whole bridge with different loading time, the dynamic response characteristics of cable-stayed bridges caused by different breakage time were analyzed. According to the relevant regulations on cable breakage in recommendations of stay cable design, testing and installation of PTI (Post Tensioning Institute) in American, a calculation method of the effect of single cable breakage on the loaded cable-stayed bridge was put forward, that is, the amplification of structural weight and the live load of automobile. The results show that the method of reverse loading is more accurate to simulate the breakage of cables and the impact to the whole structure. The dynamic response of the whole structure varies with the change of shock time Td. When Td is larger than the natural vibration period of the whole stricture, the most obvious dynamic response of the structure will occur during the shock period, when Td is smaller than the natural vibration period of the whole stricture, the most obvious dynamic response of the structure will occur during the free vibration after the shock. On the other hand, the maximum value of the action is also analyzed more realistically according to the amplification of the full-bridge load caused by the cable breakage in PTI recommendation. Under the load combination of reverse amplification load, dead load and the driveway distribution in cable failure of cable-stayed bridge, the maximum displacement of main girder appears in the area of the span center of mid-span. Under the same vehicle load distribution, the maximum difference of vertical displacement appears near the span center of mid-span, compared to the intact structure. The farther the distance from tower and supporter, the greater the impact is. The maximum difference between the intact structural cable force appears in the adjacent cable of the failure cable. And it further verifies that the maximum dynamic amplification coefficient 2.0 due to the single cable damage obtained by the quasi-static method in PTI recommendation is reasonable. However, if the failure of more than two cables are considered at the same time, it is insufficient to design the safety reserve according to the dynamic amplification coefficient 2.0.
Last Update: 2017-12-18