In-plane Nonlinear Stability Of Elastically Supported Circular Steel Shallow Arches

Arch structure has the advantages of elegant shape,good mechanical performance and so on.Arch structure is a very reasonable structure form widely used in building and bridge engineering because of larger stiffness and high bearing capacity.As a kind of common construction materials,steel is an ideal structural material with the mechanics performance advantages of light weight,high strength and good toughness and with the construction advantages of getting and processing.Combining the advantages of steel material and arch structure,steel arch is widely used in the field of construction engineering.However,this structure also has a lot of problems in design.Arch structure is mainly in compression condition and the steel cross section is small,which cause the stability problem is prominent.Besiades,arch supports must have certain stiffness to ensure that the arch has adequate axial force.In practical engineering,arches are often supported by other structural members,it is impossible to make completely rigid supports,especially for shallow arches,which ratio of rise to span is small,supported stiffness becomes very important in design.It need further research about the influence of supported stiffness on the stability of steel arch.This thesis focuses on in-plane nonlinear stability performance of elastically supported circular steel shallow arch.Firstly,geometric nonlinear buckling theoretical derivation of circular steel shallow arches with horizontal spring supports are carried on.Secondly,elasto-plastic stability bearing capacity in plane of circular steel shallow arches with horizontal spring supports are studied.Finally,the numerical simulation and analysis of elasto-plastic stability bearing capacity is carried out and the design method of circular steel shallow arches with horizontal and rotational spring supports is studied.The main achievements of this thesis are summarized as follows.(1)The internal force linear solution of the circular steel shallow arch with horizontal and rotating elastic spring supports is given combined with the strain displacement relationship.Compared with the finite element analysis results,theoretical derivation is proved right.(2)The relationship of equivalent horizontal spring stiffness Kh and equivalent rotating spring stiffness K? of arch supporting columns of steel arch is studied.The relationship formula of Kh and K? are given and it is proved to be correct.(3)The experimental research of in-plane stability bearing capacity of six bending circular elastic supporting arches whose rise to span ratios are 0.1 and 0.2 is conducted under vertical uniformly distributed loads of all across.The instability failure mechanism of the elastic supporting arch is revealed.By comparing the test results with the results of numerical simulation,it is proved that the finite element numerical calculation result has a high precision.The finite element analysis method can be used for the further research of in-plane stability of elastic supporting circular steel arch.