Mechanical Analysis And Design Method Research On Fabricated Special-shaped Steel Lattice Column

In the field of prefabricated steel structure,research institutes and enterprises have developed new prefabricated steel structure systems.However,the steel tube bundle columns and multi-cavity steel tube columns studied at present still have problems such as complex structure,inflexible layout and low standardization of components.In order to improve the exposed column problem of traditional prefabricated steel structure buildings,a new type of prefabricated special-shaped steel lattice column（SSLC）was proposed.As a new structure,SSLC does not have academic research as a theoretical support,and there is a lack of supporting theoretical calculation formula and design method.Therefore,the mechanical analysis and design method of SSLC was studies in this paper.The main work is as follows:（1）The theoretical calculation formulas of SSLC are deduced.The basic size of SSLC is determined according to the structural requirements in the specification.The lateral stiffness calculation formula of SSLC is derived by using the Vierendeel Truss Theory.The calculation formula of ultimate bearing capacity of SSLC is obtained by double coefficient product method,and the calculation formulas of slenderness ratio influence coefficient₇)and eccentricity influence coefficient₀)are given.This paper gives the design method and suggestion of SSLC（2）The compression performance of SSLC is analyzed.A total of 75 ABAQUS finite element models were designed to study the influence of section form,slenderness ratio and eccentricity on the ultimate bearing capacity of SSLC.The results show that the ultimate bearing capacity of SSLC is positively correlated with the number of columns.With the increase of column height,SSLC gradually changes from strength failure to instability failure,and the influence of column height on the ultimate bearing capacity of L-SSLC is more significant.The ultimate bearing capacity of SSLC under eccentric compression decreases,but the ductility increases.The finite element simulation verifies that the ultimate bearing capacity formula proposed in this paper is feasible,and the safety factor is 1.11～1.64.（3）The lateral performance of SSLC is analyzed.The variable parameter analysis of SSLC is carried out to study the influence of the sectional inertia moment of column limb,spacing of column limb,sectional inertia moment of lace plate and the number of lace plate.The research shows that the main lateral force resisting components of SSLC are column limbs and lace plates along the load direction,and other column limbs provide sufficient safety reserves for SSLC.Compared with other parameters,changing spacing of column limb has the greatest impact on the lateral stiffness of SSLC.The finite element simulation verifies that the calculation formula of lateral stiffness proposed in this paper is feasible and the error is less than 13.5%.（4）The mechanical properties of SSLC in the framework are analyzed.The mechanical properties,deformation and failure process of the frame under monotonic horizontal load and low cyclic load are analyzed respectively.The research shows that the stiffening girder can make the column limbs work together.The mechanical properties,deformation and failure process of SSLC in the framework are basically the same as those of a single column.SSLC framework has good seismic performance and energy dissipation performance,and the positive and negative mechanical properties maintain high consistency.