Study On The Stability Performance Of Q460 High Strength Steel Columns With Two Stiffened Plates Under Eccentric Compression

With the continuous development of production technology,the application of high-strength steel in structural engineering such as buildings and bridges is becoming more and more common.Due to differences in the mechanical properties of materials,the effects of initial defects,and processing technology,the overall stability of high-strength steel members and ordinary strength steel members is significantly different.At present,scholars at home and abroad have conducted some researches on the overall stability performance of high-strength steel solid-web members,and have achieved certain results;little research has been done on the overall stability performance of high-strength steel lattice members.China's current steel structure design code for the overall stability design of high-strength steel compression-bend lattice members still follows the overall stability design method of ordinary strength steel,which does not give full play to the advantages of high-strength steel.In this paper,through a large number of finite element simulations,the stability performance of Q460high-strength steel biased double-limbed slab columns is studied comprehensively and systematically,and design methods and calculation formulas are proposed.In this paper,the finite element analysis is performed on the overall stability of the two-limbed slab columns with three types of limbs: channel steel limb to limb,channel steel back to back,and H-beam under simple support and eccentric compression at both ends.The effects of the number of slab plates,the distance between the limbs,the size of the limbs,the eccentricity and the overall initial bending on the ultimate bearing capacity of the slab columns were analyzed by the finite element variable parameters.The results show that the increase in the number of slab plates can significantly increase the ultimate bearing capacity of the slab columns in and out of the plane around the imaginary axis.The number of slab plates is most reasonable when the ratio of the net distance of the slab to the column length is about 0.1.The effects on the overall stable bearing capacity of the stigma columns with different limbs around the virtual axis are different,and are expressed as: channel steel back-to-back> channel steel limbs to limbs> H-shaped steel;As the size increases,the ultimate bearing capacity in the plane of the bending moment acting on the slab columns is increasing and the growth rate is increasing;the ultimate bearing capacity in the plane acting on the bending moment of the slab columns is increasing but the growth rate is decreasing.;Stub columns with larger limb sizes are less affected by the column height,and changes in column height have a greater impact on the ultimate bearing capacity of the slab columns outside the plane;changes in eccentricity have a limit on slab columns with smaller lengths The effect of bearing capacity is greater than the effect on the ultimate bearing capacity of slab columns with relatively long slenderness.When the overall initial bending changes fromL/1000 to L/100,the ultimate bearing capacity of slab columns decreases by about 26%.When bending increased from L/3000 to L/1000,the patch panel The ultimate bearing capacity dropped by 3%,and Q460 high strength steel plate column conjugated affected initial bending deformation is less than Q235 plate column conjugated affected the overall initial bending.Compared with ordinary strength steels,high-strength steels are less sensitive to geometric initial defects.In addition,this paper calculates the overall stability coefficients of 420 Q460high-strength steel eccentrically-compressed double-limbed slab columns with eccentric compression in the form of bending moments around the virtual axis and out of the moments;the calculation results are compared with the design of steel structures in China For comparison,the selection of the curve type of this type of slab column is recommended.At the same time,based on the formula of the stability coefficient calculation formula in China's steel structure design code,the defect coefficient in the formula was improved,and the Q460high-strength steel biased double-limbed slab columns were subjected to the bending moment in-plane and out-of-plane moments around the virtual axis.A more accurate calculation formula has been formulated for the overall stability coefficient,which provides a reasonable and reliable design method for engineering applications and research.