Type Selection And Parametric Design Of Weaving Main Arch Structure Of Ancient Timber Arch Lounge Bridge

The ancient wooden arched corridor Bridge is a very precious historical and cultural heritage in China,but the protection and maintenance of The wooden arched bridge,from the beginning of construction to use,have relied on past experience and lacked scientific basis.This can easily lead to resource waste and difficulty in ensuring structural safety.Therefore,this thesis conducted research on the selection and design methods of the main arch structure of the wooden arched bridge.The main content is as follows:(1)The investigation surveyed the main design parameters of ancient wooden arch bridges,analyzed the force mechanism of the main arch structure,and based on the study of the response of the main arch structure to changes in the span ratio of the threesection Miao structure,obtained a reasonable range of span ratio for the main arch structure between 0.16 and 0.22;(2)The mathematical relationship between the plane coordinates of the endpoint of the main arch structure seedling pole has been determined.With the optimization objective of minimizing the deviation between each bull head of the main arch structure and the reasonable arch axis,the design formula for the ratio of the length of the fivesection diagonal pole and the three-section diagonal pole,β,has been obtained.The design formula for the diameter of the seedling pole section is calculated and a simplified method for calculating the internal forces of the main arch structure under uniformly distributed loads is proposed.The calculation steps for verifying the carrying capacity of the seedling pole are organized.(3)Use the Geometry Gym plugin to create a parametric model of the main arch structure in GH(Grasshopper),and perform interactive data conversion with SAP2000 for finite element analysis.By using the finite element method,the response of the main arch structure can be calculated as the span ratio changes.By comparing the results with those of the three-section pole structure calculation,the feasibility of determining the optimal span ratio of the main arch structure based on the three-section pole structure is verified.(4)proposed a design process for the main arch structure,and improved the design of the main arch structure of a landscape timber arch bridge in Taishun according to this process;finite element models were established for both the original design and the improved design by adjusting parameters in GH,and their calculation results were compared.The results show that the design method proposed in this thesis can economically,conveniently,and reliably design the main arch structure of timber arch bridges.