Parameters Analysis And System Optimization Of Irregular Arch-shaped Bridge With Multiple Arches And Large Cantilever

The butterfly-shaped arch bridge has the characteristics of inclined arches and more arch ribs.Its spatial composition is unique and structural behavior and stress state are very complex.The aesthetic requirements and force performance are often contradictory,which often leads to optimality or even unreasonableness between its structural design and stress state.At the same time,most of these structures have the functions of vehicle and pedestrian at the same time.The horizontal width is generally wider,the lateral layout is more complex,the cantilever plate usually adopts a large cantilever,the shear lag effect and large cantilever effect of the structure are obvious,and the lateral deformation and the structure of the structure are affected.The force state is closely related to the overall layout parameters of the structure.The existing system optimization calculations are mostly directed to cable bridges or ordinary tied arch bridges.The optimization of butterfly arch bridges is less,and most of the optimization calculations are based on plane beam models.The beam model cannot accurately reflect the wide box beams.Large cantilever structure stress and displacement state.Therefore,it is necessary to carry out parametric analysis and system optimization research for this kind of special-shaped arch bridge,to grasp the optimization design of the complex three-dimensional structure as a whole and to accurately analyze the influence of the wide girder girder and consider the local state.In this paper,aiming at the difficulties in the optimization design of multi-arch-ribbed butterfly arch bridges,considering the characteristics of the wide girder girder and the space complexity of the girder,the 3D solid model of ANSYS is used to establish the refined 3D solid model and the MATLAB hybrid programming is used.The total cost is the objective function and the selected structural displacement and stress parameters are used as constraints,and a typical multi-arch rib butterfly arch bridge is optimized overall design:1)Select the minimum design parameters that can uniquely determine the structural design status and optimization goals,and establish the refined parameters finite element model of the bridge.The original design values are assigned to the design parameters and the load calculations under different load conditions are performed.The analysis of the results shows the accuracy of the modeling method and the applicability of this idea for the optimaldesign of such arch bridges.Prepare your work in one step;2)The general flow and method of parameter sensitivity analysis are introduced.The sensitivity of the selected 15 design parameters are analyzed in turn.The sensitivity of the selected parameters and the influence of each parameter on the force response of various parts of the structure are determined.The impact of each design parameter was sorted and the range of design parameters was given;3)The force characteristics and calculation methods of the diaphragm beams of the wide box girder are introduced.The diaphragm plate of the wide box girder of the butterfly arch bridge relied on by this paper is regarded as a three-span continuous beam supporting different rigid bearings.The forces and deformations under different loading arrangements and geometric parameters of different structures are calculated.Reference values for the range of values of some design parameters are given.At the same time,suggestions are also given for the transverse design of transverse diaphragms.4)A detailed and accurate calculation process for the amount of structural material is given.The particle swarm algorithm is selected as the optimization algorithm of this paper.The displacements and stresses of the structure are selected as constraints for the optimization calculation and the selected value range of the design parameters is determined.The data exchange between ANSYS and MATLAB is set up,the constraints are assembled into the derived structure cost function,the complex multi-parameter constrained optimization design is transformed into an unconstrained problem,and the structural cost and stress state are taken as the goals for the structure.Overall optimization calculation.The optimization calculation method proposed in this paper considering the stress state of the heterotypic arch structure is not only applicable to complex three-dimensional structures but also can accurately analyze the influence on the structural stress state with wide box.At the same time,the total cost of the structure is reduced.It will help deepen the understanding of the mechanical behavior of this type of arch bridge and provide some reference for the design and calculation of such bridges.