Vulnerability Analysis Of Concrete Cable-stayed Bridges

In the recent decades, the cable-stayed bridges, with many particular merits such as economy, reasonable structure style and attractive appearance, have been a dominant bridge style among long span bridges. However, it is inevitable that there come forth some kinds of damnifies and diseases at the bridge structures, all of which will cause a series of problems such as fall of structural load-carrying capacity, durability and service ability. These problems are shared by lots of existed cable-stayed bridges. Based on Taian Yangtse River Bridge, a cable-stayed bridge located in Luzhou City, Sichuan Province, structure members and locations which are damageable are successfully identified by mechanical calculation analysis and bridge disease inspection in this thesis. These research results are instructional for the design, construction, damage identification and health monitoring of bridges.The main contents of this thesis are as follows:In the first chapter, the development history of concrete cable-stayed bridges across the last decades is firstly reviewed. Then the importance and significance carrying out research of vulnerability analysis of concrete cable-stayed bridges is addressed. In the end of this chapter, the research objectives and contents of this thesis are introduced.In the second chapter, the vulnerability analysis of Taian Yangtse River Bridge at the normal service condition is conducted. The main work of this part is to identify vulnerable structure members and locations. Also parametric oscillation of cables is illustrated, and the cables which are apt to be induced to parametric oscillation are judged.In the third chapter, based on disease inspection of concrete cable-stayed bridges, According to the structure characteristics of the cable-stayed bridge ,the diseases have been summarized systematically from the aspects of cables, pylon, girder, anchorage zones, bridge deck and so on. Also the causes of these diseases are discussed.In the fourth chapter, base on the bridge finite element analysis, variation characteristics of structural static and dynamic performance are analyzed due to vulnerable locations. According to these characteristics, a set of cable monitoring project is put forward.The last part of this thesis is the conclusion, which summarizes the main works and research results of this thesis, and also indicates some projects that need to be further researched.