Study On Hollow Thin-Wall Pier Structurue

The thin-walled hollow pier is an important lower part of the high-span long-span bridge.Its stability is also an important problem in the safety of the bridge structure.Therefore,it has important engineering application value for the study of the stability and local structure of the thin-walled hollow pier.In this paper,the thin-walled hollow piers in the bridge and the construction stage are reduced to the central compression bars under different boundary conditions,and the whole stability is studied.The thin-walled hollow piers are regarded as the components of the thin plate,and the local stability of the thinwalled hollow piers is carried out The critical thickness and ultimate aspect ratio of the known plate width are studied.This paper mainly carried out the following research work:(1)Based on the differential equation of the bar,the Bessel differential equation is used to derive the lower end consolidation and the lower end of the lower end.Under the two boundary conditions,the equal section and the variable cross-section pier are used in the vertical distribution load Of the critical load.(2)Under the combined action of vertical distributed load and concentrated load,the vertical distributed load is equivalent to the concentrated force acting on the top of the pier according to the principle of load equivalence,and the pier is unstable under the effect of equivalent force and concentrated force.The critical load of the concentrated force is deduced,and the expression form of the formula is unified.The results show that the formula satisfies the actual requirements of the project.(3)Based on the isotropic and orthotropic theories of the plate,the formulas for calculating the critical stress of the plate during the elastic phase and the elastic-plastic phase are deduced.Combined with the general stress-stress formula,the thin-walled hollow pier is regarded as the member of the thin plate,Taking the overall instability of the pier as the control condition,the critical thickness of the thin-walled hollow piers with equal section,variable cross-section and single-box and double-chamber cross-section under the condition of satisfying the condition and the known plate width are deduced.(4)The warping coefficient and the constraint coefficient involved in the derivation of the critical stress formula of the thin plate are further discussed.The calculation formula and the correspondence formula of the constraint coefficient and the warping coefficient of the thin-walled hollow pier are calculated.The value of the parameter.(5)The first class stability analysis is carried out on the thin-walled hollow pier by using ANSYS.The critical thickness of local instability is obtained by trial and calculation,and the correctness of the formula is verified by the formula.The results show that:(1)It is feasible to calculate the critical thickness of the thin-walled hollow pier by using the formula of the same plate and the results of the finite element analysis.(2)As the height of the pier increases,the critical thickness of the sheet decreases.This is mainly due to the increase in the height of the pier,the critical stress decreases,resulting in the critical thickness is also reduced.(3)The results calculated by Orthotropic plate theory are closer to the results of finite element analysis than the results of homogeneous plate theory,and the accuracy of the formula is higher.This is mainly due to the orthotropic plate theory included in the elasticity of the material.