Structural Characteristics Analysis Of Steel Reinforced And Concrete-filled Steel Tube High Pier

With the deepening development of western regions, many high-pier and long-span bridges are under construction. This paper proposes a new structure that combines the stiff skeleton and concrete-filled steel tube combinational pier to use in high-pier and long-span bridges. This combinational structures has integrated the advantages of stiff skeleton concrete and concrete-filled steel tube c, which has the characteristics of high bearing capacity, great anti-seismic property and simplified construction formwork. If it is applied in high pier, it can effectively reduce the section size of pier, which will be convenient for the construction of high pier. By combining actually engineering practices, this paper analyzes the mechanical properties and studies the anti-seismic property of stiff skeleton and concrete-filled steel tube combinational pier through tests and finite element analysis. The main content and conclusion of this study are as the following:By combining the research results of three dimension stress hoop enforcement of concrete, efforts are made to study the stress mechanism of stiff skeleton and concrete-filled steel tube combinational pier, and discuss the advantages and deficiencies of stiff skeleton and concrete-filled steel tube combinational pier. Research is conducted on the computational method for the bearing capacity of new combinational pier, the computational formula of normal section bearing capacity, and in the meantime, simplified practical computational method based on superposition principle is also proposed.Six test pieces of stiff skeleton and concrete-filled steel tube combinational pier with different steel content are produced, which are divided into two groups. The axial compression and eccentric compression tests are conducted in the compression machine, and the whole test process is described. Through test phenomenon and data analysis, we discuss the stress damage mechanism of stiff skeleton and concrete-filled steel tube combinational pier, analyze the load-displacement relation curve and the longitudinal and transverse strain curves of test piece, and study the stress redistribution rules of external structural steel, internal steel tube and core concrete.With the specially Xiapingchuan long span bridge at the section of Guizhou -Panxing Highway as the background, we analyze the bridge structure form selection, build the finite-element contrastive analysis model between the stiff skeleton and concrete-filled steel tube combinational pier and the common reinforced concrete pier, conduct contrastive analysis and research of static structural indices, such as the structural displacement and deformation, internal force distribution of girder and bearing capacity, conduct buckling analysis of the initial defects of new combinational pier bridge, and select multiple seismic waves to analyze the study the time interval of new pier bridge. The anti-seismic analysis shows that the combinational pier has significant restraint on concrete, which can significantly slow down the time of concrete failure, it has great anti-seismic performance, and it can meet the three seismic fortification levels of "no damage in small earthquake, repairable damage in medium earthquake, and no collapse under strong earthquake". The stiff skeleton and concrete-filled steel tube combinational pier has great application prospects in the mountainous areas of West China.