Damage Identification Of Long-span Cable-stayed Bridge Cables Using Static Methods

In recent years, with the development of scientific technology and social and economic progress, cable-stayed bridge structure is more and more popular in the world because of its beautiful structure modeling and strong spanning capacity. As cable-stayed bridge span increases constantly, cables at high stress will be inevitably corroded and damaged because of outside unfavorable factors. Because cables are the most important component of the cable-stayed bridge structure, cables damage can produce to the whole bridge safety hazard. Therefore, how to identify accurately and timely the cable damage plays an extremely key role for the healthy operating of the long-span cable-stayed. Based on the Edong Yangtze River Highway Bridge for engineering background, with cable damage as the breakthrough point, this paper studies that cable damage produces influence to girder deflection and cable stress change. The main research work includes the following aspects:(1)On the basis of plenty of domestic and foreign literatures, this paper briefly introduces the advantages of cable-stayed Bridges, and recent development status and parts of stay-cables bridge replacement example.(2) Because cable-stayed bridges are prone to damage, this paper expounds the main cause of damage and protective measures, the cable detection and evaluation methods, cable replacement of purpose and mission.(3) Based on the space bar system finite element modeling theory, three-dimensional finite model of the cable-stayed bridge Edong Yangtze River Bridge is given. Consider cables sag, this paper corrects the modulus of elasticity, it can make the model better reflect the real bridge condition.(4) According to the design information, this paper proceeds the static analysis of the Edong Yangtze River Highway Bridge with dead load (structure self-weight and phase second dead load),and determines the structure "zero" of the mechanical characteristics, and gives the whole bridge under stress state of structural response.(5) It analyzes the cable damage and cable damage casing the change discipline of girder deflections, and finds out the girder for most sensitivity position. It also analyzes the cable stress change under the cable fracture and the cable change, and it is concluded that the most easily damage position when cable stress change.(6) Comprehensive consideration of the girder of linear and the change regular of cable stress, it determines the distribution of cable damage for the position and damage degree, which provides practical basis for cable protection, maintenance and replacement. (7) This paper analyzes the whole temperature and temperature of cable (tower) girder of cable-stayed bridge the influence for cable stress for change, which can provide the reference value for girder and the cable stress.