| Continuous rigid frame bridge is a combination of pier girder consolidation system, its comprehensive advantages of T rigid frame and continuous beam bridge, and also dismissed the former existence insufficiency of expansion joint system transformation and the latter, with good integrity, reasonable structure, convenient construction, therefore widely used in the construction of the bridge in our country. The stability of state research for long-span continuous rigid frame bridge construction process has deeper at home and abroad, but most of the literature research is on double limb thin-wall high pier, and the study of stability of variable cross-section single limb thin-wall high piers is less,its stability has its characteristics.At the same time, the actual construction process of bridge pier in existence more or less the initial defects,(such as the pier top offset, material defects, etc.), the influence extent of single limb thin-wall high piers of research literature is less, now has a certain research significance.Based on single limb high pier continuous rigid frame bridge cantilever construction process and the stability problem of state to conduct research, the main research work and achievements are as follows:(1) Expounded the development of continuous rigid frame and research status at home and abroad,introduces the basic concepts of structure stability study,At the same time also introduces the structure of the engineering structure stability evaluation index and criterion.(2) Using finite element software Midas/Civil build Hong yanxi bridge finite element model of the whole bridge, and carries on the static analysis,the calculation results and the design results are basically consistent, prove the model calculation accuracy.(3) Using Hong yanxi bridge each state, considering all kinds of construction load(such as gravity, wind load structure, construction load, temperature effect,etc.), under the influence of bridge are analyzed in the stability of the whole construction process. Studies showns lateral wind load is the main factors influencing the stability of high pier; Across the maximum cantilever state, the lowest one side hanging basket fell to the impact of load on the structure stability, the impact of the largest; The whole bridge stability significantly increased after closed,Lateral wind load is still one of the important factors to a single limb high pier continuous rigid frame bridge stability.(4) Analyzed the influential factors of the structure stability. Results show that considering the geometric nonlinear effect can reduce the stability of the structure, the stability coefficient under the maximum cantilever state fell by 4.2%, the stability of the whole bridge operation state decreased by 8.8%, the whole bridge operation state effect more sensitive; Take initial defects(offset, material defects) loaded effect on the stability of the high pier continuous rigid frame bridge, if material defects occurred in 1/4 pier height, there the most unfavorable influence on stability of structure, stability coefficient decreased by 3.9%; The study also found that under the condition of high pier equal, while the stability factor of single limb pier pier was 44.6% higher than the double limb, but single limb pier pier top bending moment value is much larger. Pier height and wall thickness variation of single limb high pier shafts of the effect on the stability of the continuous rigid frame bridge, found that high pier in 30 m and 50 m range stability coefficient decreased quickly, when the pier high rate decreases after more than 60 m, the stability of piers increases along with the increase of wall thickness, and Increasing rate decreases with the increase of wall thickness. |
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