Studies On Mechanical Behavior And Design Method Of Steel Bending-Torsion Box-Section Member And Lattice Dentritic Column

In Suzhou Taiping Finance high-rise Building,steel bending-torsion boxsection members were widely used and cross-pulling-beam lattice dentritic columns were used as vertical support members to satisfy the architects’ demands for hemline-like large scale steel structure.Steel bending-torsion boxsection member is the box-section member that twists around the centroid axis and bends longitudinally.Nowadays,bending-torsion box-section member has been widely applied in long-span spatial structure at home and abroad because the member is able to adapt to complex building shape.The limb columns,that are formed by hot bending,of cross-pulling-beam lattice dentritic column are tied by cross-pulling-beams.It has better mechanical behavior and overall performance compared with traditional solid-web dentritic column and planar Y-type column.The studies on steel bending-torsion box-section member mainly focus on the examination for engineering,but the design method of bending-torsion box-section member is lacked which results in the difficulty on widely use in actual engineering.The studies on dentritic column concentrated on mechanical performance of Y-type column under axial compression.The test study on cross-pulling-beam lattice dentritic column and test data are lacked.The steel bending-torsion box-section members used in Suzhou Taiping finance high-rise building was studied.The numerical analysis models of steel bending-torsion box-section member were formulated by the FE software ABAQUS.The mechanical performance and the failure mode were researched and the design calculation formulas were proposed.The axial compression and pseudo static tests were launched on two scale models.The mechanic performances of crosspulling-beam lattice dentritic column under axial compression and pseudo static were investigated.The work of this paper is as follows:(1)The steel bending-torsion box-section members used in Suzhou Taiping finance high-rise building was counted and the standard section was proposed.On the basic,the numerical analysis models of steel bending-torsion box-section member under axial tension,axial pressure,positive bending moment and negative bending moment were formulated by the FE software ABAQUS.The correction of the models were verified by the tests on papers.(2)A large number of numerical analysis calculations for steel bending-torsion box-section member were calculated,the mechanic performances and failure modes were known.The parameters of the steel strength,the bending degree,relative twist angle and the steel plate thickness were studied to obtain their effects on the yield bearing capacity of the bending-torsion box-section member.The design calculation formulas of steel bending-torsion box-section member under axial tension,axial pressure,positive bending moment and negative bending moment were proposed.(3)The cross-pulling-beam lattice dentritic column used in Suzhou Taiping finance high rise building was taken as an example.The axial compression and pseudo static tests were launched on scale models of cross-pullingbeam lattice dentritic column.The axial compression performance and seismic performance of cross-pulling-beam lattice dentritic column were known.The numerical analysis models of cross-pulling-beam lattice dentritic column under axial compression and pseudo static were formulated by the FE software ABAQUS.The correction of the models were verified by the tests.(4)The parameters of the steel strength,the number of cross-pulling-beam,the high of column,the high of inflexions of branches and the steel tube thickness were studied to obtain their effects on the mechanic performance and failure mode of the cross-pulling-beam lattice dentritic column.Different structure methods were analysed to obtain the effects on axial compression and seismic bearing capacity which provide theory evidence for design and application in actual engineering.