The Cable-stayed Bridge Construction Monitoring Its Facilities Long-term Applied Research

Cable-stayed bridge is a new type of bridge structure which has been developed in recent decades and enjoys the characteristics of concinnity, slenderness and strong span ability. The type of bridge is a high redundant structure system. The segmental cantilever construction technique is often applied to the construction of cable-stayed bridge. Because of the slenderness of the whole structure and the deviation of the alignment which are not easy to be controlled, the stress and strain of the structure are much more complex during construction phases and using phase when all kinds of loads placed on the structure. At the same time, the issue concerning the durability of the bridge, especially the anti-erosion ability of the cable and anchorage is still remaining unsettled. During the lifecycle of cable-stayed bridge, the construction phase and consumption phase are both phases of high risk. Supervision over the construction now has been paid high attention to by bridge engineers and many theories and methods have been developed. The supervision methods adopted frequently are these: Calmar filtering method, self-adapted control method, giving girder and cable some tolerance method. The three methods are all based on measure of the real structure. During the construction to measure the practice instance of structure accurately then to do some measurements to control the alignment and stress and strain of the structure to optimum is an important part of supervision. During the using phase especially the consumption phase, the deformation, the stress and strain should be measured in order to insure the service ability and safety of the cable-stayed bridge. The supervision in using phase and supervision in all phases in system should be paid more attention to.The thesis takes an the supervision of Lanzhou Yintan Huanghe River Bridge as example to introduce the theories and practice of cable-stayed bridge safety and quality control in construction phase and using phase. At the same time put forward the proposal about establishing the long-term system of cable-stayed bridge safety and quality control. The long-term system is designed in the bridgedesigning phase, applied to bridge construction phase, and used in construction bridge phase and bridge using phase. The long-term system should comprehensively measure all kinds of safe-affecting factors such as stress, strain, deformation, temperature, vibration, displacement of the bridge structure, wind power, wind direction and so on. Dealing with the datum, judging the safety of the structure, giving an alarm under abnormal conditions, are the fundamental functions of the system. Sometimes, the system should supervise the structure on real time. The comprehensive long-term supervision system can only be used in the specially long-span bridges or bridges of great importance .For economical reasons in China, so how to establish a practical long-term system is in need. The practical long-term system can be used in construction phase, loads test after bridge completed and using phase to ensure the safety and the quality of the cable-stayed bridge.