Construction Control And Procedure Optimization Of Long Span CFST Arch Bridge With Stiff Sleleton

With the advancement of science and technology, concrete-filled steel tube arch bridge with stiff skeleton has a large number of application in China. However, there are only three such bridges which the span is over400m and the relevant research data still relatively limited. This thesis is mainly about the construction process of a deck concrete-filled steel tube stiff skeleton railway arch bridge with a main span of416m. The main research works and results are as follows:1. Three methods used to calculate the cable force are introduced, and an improved cable force algorithm based on the former ones is put forward. The principle of this algorithm is simple, and this algorithm is better to solve the prolems existing in the three common cable force algorithm. The cable force and steel tube stress of each constrction stage can also meet the requiements of the code.2. The cantilever erection of the stiff skeleton finite model is established according to manufacturing coordinates. Then the installation elevation of each segment and control line in each construction stage is calculated, and then the effect of weld width caused by pre-elevation and temperature load on the structure construction line is studied. The results show that the increased weld width between adjacent segments caused by pre-elevation can be ignored, but the effect of temperature on the control line and the closure segment must be considered.3. The effects of the construction sequence and the division number of the segments on the force, deformation and stability in the construction process of wrapped concrete of arch ring are studied. The results show that, in the construction process of wrapped concrete, the construction sequence has a little influence on the stability but great influence on the stress and displacement of the structure. However, the reduced number of the segments can improve the stability of the structure to some extend. It will cause an adverse impact on the force and displacement of the structure after the closure of arch ring, so the reasonable construction sequence and the segment number should be adopted.4. A number of issues of concrete-filled steel tube arch bridge with stiff skeleton in the construction stage of wrapped concrete of arch ring were analyzed and discussed, and some reasonable suggestions are given.