Research On The Flexural Behavior Buckling Of Q460 High Strength Steel Double Component Battened Columns Under Axial Compression

With the improvement of the productivity and production process,the strength and performance of steel have been continuously optimized in recent years,and the application of high-strength steel in large span buildings and high-rise buildings is becoming more and more common.The stability problem of steel members has been a hot topic of scholars all over the world.Therefore,with the application and development of high strength steel,more and more scholars have studied the overall stability performance of high strength steel with solid web section members such as channel and I-shaped.Latticed members have many advantages,such as reasonable material distribution,good torsion resistance and more industrialized.They are widely used in high-rise buildings,industrial plants,platform structures and high support system.Compared with the solid web section members,the latticed columns are easier to achieve the equal stability around the two spindles,and can guarantee the bending performance of the component under the same axial resistance,and save material.Therefore,it is necessary to study the overall stability performance of the high strength steel latticed members.In recent years,domestic and foreign scholars have made some remarkable achievements in the performance of bending buckling of high strength with solid web section axial compression members.But the flexural buckling properties of latticed columns with high strength steel are rarely studied,and the complete,accurate and reliable calculation methods still need to be studied.Therefore,according to the condition of our country,it is necessary to study the performance of bending buckling of high strength steel latticed columns under axial compression,and improve the relevant design method and put forward a new calculating formula of column curve.It is also meaningful to supplement and perfect the high strength steel code for structural design.The torsional buckling and flexural buckling hardly occurs when the latticed axial compression members losing overall stability,and the flexural buckling around the main axis of the cross section often occurs.Therefore,the performance of elastic and elastoplastic bending buckling of Q460 high strength steel axial compression double limbs battened column around the two main axis were analyzed at first.And the channel limb section(back to back,limb to limb),H-section and under the simply supported boundary condition were considered.Refer to engineering practice and relevant code,some main parameters were studied in this paper,such as the style and size of limb,the size of batten plate,the number of batten plate and the limb distance,and initial geometric defect(initial bending).The research showed that the elastic and the elastoplastic flexural buckling bearing capacity of the battened column around real axis increased with the increase of limb size,but the length of column was longer,the rate of increase was becoming smaller and smaller.The research showed that the elastic and the elastoplastic flexural buckling bearing capacity of the battened column around imaginary axis increased linearly with the increase of batten plate size;when the width of batten plate size was increased by 60%,the elastic and the elastoplastic flexural buckling ultimate bearing capacity increased about 5%on average;when the ratio of blank spacing of the batten plate to the length of the column is equal or greater than 0.1,increasing the number of batten plate can greatly affect the capacity of the elastic and the elastoplastic flexural buckling;however,when the ratio is less than that,the effect of increasing the number of batten plate is not obvious;when the length of battened column,the number of batten plate and the size of batten plate were fixed,the flexural buckling capacity the of the elastic and the elastoplastic flexural buckling of the battened column around imaginary axis increased with the increase of limb distance;but the increasing amplitude decreased gradually;with the increase of the overall initial bending rate,the ultimate bearing capacity of the battened column is obviously decreased,but the degree of reduction is becoming smaller and smaller.Then,the overall stability coefficient of 576 Q460 high strength steel axial compression double limb battened column around real and imaginary were calculated,and the material nonlinearity and geometric nonlinearity(initial bending)were considered.By comparing with the main design codes of steel structure at home and abroad,some suggestions for selecting the type of column curve of this kind of axial compression members are put forward.Finally,the overall stability coefficient of 124 Q460 high strength steel axial compression double limb battened column around real and imaginary were calculated,and the limb section was I-shaped,and the material nonlinearity,initial bending and residual stress were also considered.