Study On Bearing Capacity Of Ancient Wood Members Based On Cumulative Deformation And Semi-Rigid Connections

Wood beam and column members are important force part of the ancient wood buildings,under the influence of the natural environment,there are a variety of cumulative deformation,such as wooden beams,wooden column of the initial deflection deformation,the end lateral displacement of the wooden column.The existence of cumulative deformation has a negative effect on the mechanical properties of the wood members,and even threatens the safety of the ancient wood buildings.Based on the orthotropy of wood and the semi-rigid connection characteristics of ancient wood members,the formulas and numerical simulations of elastic stage and plastic stage under cumulative deformation are carried out in this paper.The main research contents are as follows:1.According to the computing model,the semi-rigid connection’s orthotropic elastic analytical solution of the wood beam under the uniform load and the wood column under the end axial load is deduced.For the derivation of the elastic solutions of the accumulated deformation’s wood column,In this paper,the equivalent load method is adopted,and then the effect of cumulative deformation and semi-rigid on the mechanical properties of wood members is discussed according to the theoretical formula.2.Based on the stress properties of wood members,the orthogonal anisotropy of wood is simplified to the isotropic direction of the wood,and the bearing capacity formula of the wood beam and column is deduced.According to the stress-strain relationship of the section,the bearing capacity formula of three kinds of failure types is deduced respectively.The load-displacement curve is simplified to bilinear,and the approximate deflection calculation method of the wood beam is obtained.The elastic critical load formula of the non-lateral displacement semi-rigid connecting ideal column is deduced and the calculated length coefficients for different semi-rigid connections at the ends are discussed.At last,the influence of the cumulative deformation on the bearing capacity of the column is deduced under the influence of the lateral displacement and the mid-span deflection of the column.3.In order to verify the correctness of the formula derivation,this paper builds up the numerical model of the wood members under different cumulative deformations based on Ansys.The semi-rigid connection characteristics of the ancient wooden beams and columns is simulated by applying the spring element;Under the premise of verifying the correctness of the model,the numerical results are compared with the theoretical formulas,and the numerical results are in good agreement with the theoretical formula.