Research On Safety Evaluation And Decision System Of Simple Supported Girder Bridges

By the end of 2013, the number of highway bridges which technical condition level had been rated as four or five bridges are up to 97698 in our country, accounting for 16.43% of the total number of bridges. The existence of a large number of unsafe bridges in our country highway transportation seriously threatens the safety and smoothness of the road, produced a huge hidden trouble to people’s life and property. Nowdays with the rapid growth of traffic volume and the vehicle load, through researching on safety assessment of simple supported beam bridge, putting forward a kind of effective and efficient beam bridge safety evaluation method has an important realistic meaning.In this paper, through making statistics of 41 cases of simply supported beam bridge accident occurred from 2001 to 2013, making statistical analysis to the causes of the accident and the direct and indirect losses. By calculating the simply supported beam bridge accident robustness index, proposed improvements to enhance the robustness of simply supported beam bridge. By from staff, vehicles, bridges, and environmental these four aspects, through analyzed the factors which affecting the safety performance of simply supported beam bridges in detail, and summarized 28 safety factors of simply supported beam bridge. Through processing analysised the basic data of the simply supported beam bridge form Taiyuan city, Xinzhou city, Datong city and Lvliang city, and used the principal component analysis to selection the index of the simply supported beam bridge, and then used the rough set theory to calculation the weight of each index. Based on the extension theory, determining the classical domain and the section domain of the security evaluation index, and finally established the safety evaluation system of simple supported beam bridge based on the theory of extension, and proposed a practical and effective evaluation method to identify the safety conditions of the simply supported girder bridge.Based on Visual Basic application development platform, I had developed better visual interface, practical, convenient and efficient safety evaluation system of simply supported beam bridge. In this thesis, I had Used this program to made safety evaluation of Xuejiahui bridge, and compared with the result of the technical condition of this bridge, The conclusion showed that the results of the safety evaluation of the program and the actual test results are in good agreement resistance, proved that the program are accurate and feasibility.Through the study of this paper, proposing a method to identify the safety conditions of the simply supported girder bridge based on the theory of extension, and developed a program to identify the safety conditions of the simply supported girder bridge. Then can greatly improve the precision and efficiency of the safety evaluation of the simply supported girder bridge, it has important social significance and realistic significance to promote the development of safety evaluation of the simply supported bridge in our country.