Experimental Study And Seismic Response Analysis Of New Steel-concrete Composite Bridge Pier Models

The new steel-concrete composite pier is a new type of structure obtained by assembling concrete filled steel tubular segments.Because this kind of piers can be prefabricated in factories and the site construction is relatively simple,which greatly reduces the construction cost,the study of this kind of piers is of great significance.However,due to the lack of research on this kind of new structure at home and abroad,the popularization and application of this kind of pier is hindered.So there are important theoretical significance and engineering practical value in the study of new steel-concrete composite pier model.Based on the research project of the mechanical performance of steel-concrete composite pier carried out by Gansu Provincial Communications Department,this paper studies the relevant performance of such pier models by experimental research and numerical simulation.The hysteresis curve,skeleton curve and energy dissipation area of piers are analyzed in the different axial compression ratio,prestressing force and connecting springs at the bottom of piers under cyclic loading test.The results show that the energy dissipation capacity of piers increases with the increase of these three variables,and there is the most significant effect on energy dissipation when the stiffness of connecting springs at the bottom of piers are changed.Under monotonic loading test,the displacement-force curve of the top of a pier(new steel-concrete composite pier with bolted connection at pier bottom)and the change of the surface strain of the steel tube of the concrete filled steel tube section shows that with the increase of the horizontal displacement,the top force of the pier and the surface strain of the steel tube change approximately linearly,the strain is less than yield point.By numerical simulation analysis method the dynamic characteristics of this kind of pier and its top displacement,bottom shear force and bottom bending moment under seismic load are analyzed,the results show that the new pier has smaller stiffness and larger displacement of pier top under earthquake,but its pier bottom shear force and pier bottom bending moment are smaller,so further research is focused on finding a balance point.Through the experimental study and seismic response analysis of the new steel-concrete composite pier model,this paper has a certain reference value for the design and application of this new type of structure.