The Stability Study And The Risk Analysis For A Continuous Rigid Bridge With High Pier Which Overpasses Railway

In recent years, transportation has been highly developed. During the transportationconstruction, many over-pass bridges have been built in order to meet the need of mute design.The stability of those over-pass bridges were not only related to the security of themselves,but also affected roads they crossed. So, the stability of the over-pass bridge is very important,especially when it the crossed this railways that have come into use. So, it was significant tostudy the stability and the risk analysis of the over-pass bridge.In this paper, setting in the project of Chaoyantang viaduct bridge, stability of high pierwas stayed and a risk analysis of the stability of high pier in the stages of design, constructionand operation was made. Main works are as followed:1 .Established a space model of Chaoyantang viaduct bridge using MIDAS/CIVIL, alarge scale general purpose program, then calculated and analyzed the stability in differentsituation: self-stability of the highest main pier (70m) with self-weigh, longitudinal wind loadand transverse wind load after completing; self-stability of the highest main pier (70m) in themaximal cantilever state with longitudinal and transverse wind load, self-weight error andhanging basket falling during construction stage; combined different loads and analyzed thestability under different load combination; calculated the stability under the most unfavorablecombination in the maximal cantilever state; stability with self-weight, the additional deadload, temperature load, moving load, prestressing force and the braking force at the top of thepier during operation. The conclusion is that the minimum stability ratio appears at hangingbasket falls in the maximal cantilever state during construction under the condition of takingpile-soil interaction into consideration.2. This paper considered the interaction between pile and soil. By comparison, in thesame state, stability is worse in every stage when pile-soil interaction is taken intoconsideration than that of it when simulates foundation as a rigid one.3. The stability and security of the protective shed used during construction stage wascalculated and the calculation is the maximum impact load that the protective shed can bear is521kg. This statistic provided a limit to control falling objects which would protect runningtrains against risk during construction stage.4. A risk analysis of high pier stability at design stage, construction stage and operationstage was made systematically. Analyzed risk factors and calculated in analytic hierarchyprocess method. By comparing weight of all factors, the most effective factor to the stabilityof high pier appeared at construction stage, then at design stage, and then at operation stage. At design stage, the most effective factor is design error; at construction stage, the mosteffective factors are sag of pier and temperature difference in day and night; natural disastersin operation stage are more effective then human factors.