Stability And Reliability Analysis Of A Concrete-filled Steel Tube Cross-rigid Frame Bridge During Construction Period

With the development of the continual rigid frame bridge to large and super long span, continual rigid frame bridge on the design, construction and construction period of the stability and reliability have put forward higher requirements. Taking the Labajin Bridge on the Yingjing section of Yalu Speedway as the engineering background, the thesis based on finite element theory of the first category stability and the lapsed function of the construction period. Some stability and reliability analysis has been made for high pier and long span concrete-filled steel tube cross-rigid frame bridge. Several specific researches are as follows:(1) The thesis briefly introduces the difference between two types of stability and summarizes the stability of solution method. The commonly used criteria for destabilization is recommended, which is concerned stability. And the space finite element theroy of two types of stability is elaborated, which lays a foundation for the stability analysis of large-span bridge with high-pier during each construction stage.(2) The parameter sensitivity analysis for the concrete-filled steel tube main pier of Labajin super large bridge is carried on, thus the stability sensitive degree of the main design parameter is distinguished. The concrete strength grade of main pier parameter to the stability coefficient sensitive degree from larger to smaller is, outer layer of concrete strength grade, steel pipe internal concrete strength grade. The steel tube geometric size of main pier parameter to the stability coefficient sensitive degree from larger to smaller is, steel pipe dimension fo mian pier, thickness of steel pipe. The paralled horizontal contact of bridge parameter to the stability coefficient sensitive degree from larger to smaller is, diagonal steel-tube dimension, thickness of diagonal steel-tube, lateral steel-tube dimension, thickness of ateral steel-tube.(3) The basic characteristics of resistance of bridge structural members is studied. This dissertation studies the probabilistic model of structure member resistance for long-span rigid frame bridges during construction. It also discusses the randomness of construction loads and makes a statistical analysis about the invariableness of structural loads, construction live loads and wind loads. Meanwhile, the paper establishes a probabilistic model of the load effect combination.(4) Under the mode of the buckling failure, high pier and long span concrete-filled steel tube cross-rigid frame bridge of the reliability function is established. According to analyze various factors on change of reliability index, casting girder, construction live load, concrete intensity, wind load and hanging basket load, which influence on construction reliability of rigid frame bridge with high-pier and large-span, are obtained. The stability reliability of parameter sensitivity analysis for the concrete-filled steel tube main pier is also carried on. The concrete strength grade of main pier parameter to the reliability index sensitive degree from larger to smaller is, outer layer of concrete strength grade, steel pipe internal concrete strength grade. The steel tube geometric size of main pier parameter to the reliability index sensitive degree from larger to smaller is, steel pipe dimension fo mian pier, thickness of steel pipe.