| The fabricated flange-connected concrete-filled steel tube lattice pier has many advantages such as high bearing capacity,good seismic performance,convenient construction,energy saving and environmental protection,and is very suitable for high-pier bridges in mountainous areas.In this paper,a new type of fabricated flange-connected concrete-filled steel tube lattice pier proposed by a mountainous expressway project in Anhui Province is the backing project.The lattice pier has a novel structure and adopts the form of centrifugal concrete-filled steel tube column + inner flange connection,this form can effectively realize the construction concept of "standardized design,factory prefabrication,and assembly construction",and the construction difficulty of high-pier bridges in mountainous areas can be greatly reduced through segmental prefabrication and assembly.Therefore,this article mainly focuses on the new type of flange connection and the mechanical performance,the seismic performance of lattice piers,the optimization of key design parameters and other important issues to carry out systematic research,on the one hand,to ensure the safe application of this type of new lattice pier,on the other hand,it also provides a technical basis for the popularization and application of fabricated concrete-filled steel tube lattice pier.Therefore,the main content of this article and related conclusions are as follows:(1)According to the structural and mechanical characteristics of the new type fabricated flange-connected concrete-filled steel tube lattice pier,based on the ABAQUS software platform,a fine-tuned connection of the concrete-filled steel tube lattice pier and its inner flange that can consider multiple nonlinear couplings is established.Analyze the solid finite element model,and verify the correctness of the modeling method through the comparative analysis of the finite element analysis results and the experimental data;(2)In terms of static performance and seismic performance,the main weak points of this type of lattice pier are concentrated at the flange connection,the connection between the column and the fixture,and the column at the bottom of the pier.Among them,the flange connection is the weakest position,and the most vulnerable flange position is generally the two flanges above the bottom of the pier;(3)Under the action of compression and bending,the design parameters of flange connection such as axial compression ratio,number of bolts,flange material,flange thickness,rib thickness,short neck thickness and other flange connection design parameters have significant effects on the bending bearing capacity of this type of lattice pier;under axial tension,the design parameters of flange connection such as bolt edge distance,bolt size,number of bolts,flange material,flange thickness,short neck thickness,etc.the tensile bearing capacity of this type of lattice pier the impact is significant.On this basis,the reasonable value of the key design parameters of the flange connection is recommended,and the design scheme of the fabricated flange-connected concrete-filled steel tube lattice pier is optimized according to the suggested value,which can effectively improve the carrying capacity of this type of lattice pier;(4)Considering the calculation accuracy and calculation efficiency comprehensively,this type of lattice pier bridge can use the rod-based seismic finite element model for seismic response analysis.the height of the pier,the axial compression ratio,the steel content of the column and the arrangement of the fittings have a significant impact on the seismic response and seismic performance of this type of lattice pier,but the slope of the column has a small effect.on this basis,the seismic design optimization of lattice piers is carried out,and the seismic performance checking method of this type of lattice piers and their key components is proposed,which verifies that the optimized bridge has good seismic performance. |
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