Experimental Study On Failure Performance Of Rc Box-Section Member In The Compression And Bending State

In order to study failure modes and its influencing factors of box-section bending members,in this paper I firstly studied three box-section columns,compared the test results with the theoretical knowledge,analyzed the influences of restraints about fixed end,shear lag effect and axial compression ratio to its failure modes of box-section bending members;secondly,I used the finite element software ABAQUS for simulation analysis of the test contents to verified the correctness and feasibility of the model;and finally,I analyzed the impacts of the width-to-thickness ratio of web plate to this kind of components also using ABAQUS.Results show that:(1)When under a constant axial force and a one-way horizontal load,the box-section test-pieces suffered a bending damage while their web plates suffered a lot of shear force.There is obvious shear lag effect and effect of restraint during the failure process.The most severely damaged parts of the tensiled flange is between the fixed end and the midsection but the fixed end to the compressed flange.(2)The influences to the ultimate lateral beaming capacity of axial compression ratio is not obvious but generally shows that the bigger the axial compression ratio the greater the ultimate lateral beaming capacity.In addition,when the axial compression ratio becomes large,the test-pieces will be easy brittleness this will cause poor deformation.(3)The positive shear lag effect on the compressed flange is more obvious than that on the tensiled flange.To the tensiled flange the effect on the midsection is more serious than that on the fixed end while the compressed flange is just the opposite.Besides,the axial compression ratio did different to different kinds of flange.The restriction from the fixed end made the compressive stress of the outer wall around the fixed end increases and this affects the distribution of bending normal stress along the longitudinal to some degree.(4)The greater the width-to-thickness ratio,the smaller the ultimate lateral beaming capacity,the better the stretchability.Through experimental research,theoretical analysis and finite element simulation,I get the failure mode of a box-section member such as mentioned above and its influencing factors,and then I analyzed the effect of these factors.The results may be reference for enriching the relevant theory and follow-up study.