The Finite Element Analysis Of Mechanical Mechanism On The Covered Timber Arch Bridge

The history of the bridges is long in China and the forms is diversified. The timber arch bridge in Zhejiang and Fujian is unique with exquisite structure, and has high achievements of engineering technology and humanistic value. It solves the problem that the timber structure is applied to the long-span structure, and it’s the civil engineering culture hestage in ancient China. Recently with the people’s awereness of protecting culture relic raising, the covered timber bridges have been protected by the cultural relics departments and the community as culture hestages. Due to the limited research on the load transmission mechanism of the main arch, and the lack of theoretical basis for the protection and repairs, the study is essential on the mechanical mechanism of the timber arch.On the basis of a large number of domestic and foreign literatures on covered timber bridges, a lot of researche has studied on the load-transferring mechanism of the main arch by finite element methods to provide the reference for the design and repairs this paper. The main contents of this paper can be generalized as follow:First, the semi-rigid behavior of the timber mortise-tenon joints has been tested in the experiments. According to the load-transferring mechanism and the semi-rigid character, SAP2000is seleceted to develope a numerical model of covered timber arch bridge. The stress and deformation with different connection stiffness compared, it was illustrated that the consideration of the connection stiffness is nescesary in the analysis.Followed is the finite element simulation of the covered timber under full-span load and half-span load, the result of the inner force and displacement can be got. It shows that the woven timber arch structure system has a advantage of balancing the distribute of stress and increasing the stiffness. And the impact of the " horse legs" in the covered timber arch bridge is also studied.Finally some problems that exist in the real life is analysized, such as the influence of the gap between the components, the feasibility of repairs without disassemble.