The Overall Stability Bearing Capacity Of Cut-T Section Struts

Hot-rolled cut-T section struts are widely applied for processing and manufacture. As a kind of common monosymmetric section, overall stability bearing capacity of hot-rolled cut-T section struts deserved in-depth study.This method and finite element calculation through the combination of theoretical analysis, hot-rolled cut-T section struts about axis of symmetry generated flexural-torsional buckling and flexural buckling. The result were compared with that of the experimental result obtained before, get a series of guiding significance for engineering design. The research contents and the conclusions as follows:1、Simplified formula of the stability coefficient φb for flexural-torsional buckling of hot-rolled cut-T section struts.The calculation of stability bearing capacity of pressure bending members involves overall stability coefficient φb. In the current Code for design of steel structures(GB 50017—2003), approximate formula of stability coefficient φb for flexural members are given because of the complicity of the former. The latter is mainly used in the calculation of flexural-torsional buckling of beam-columns. In the final draft of the revised version of Code for design of steel structures, the overall stability calculation of beams has been changed to a large extent, but is still rather complicate, so that new simplified formulas of stability coefficient φb are given for I-section and H-section members under bending moment. A simplified formula for calculating out proper flexural-torsional buckling stability coefficient of cut-T section struts by fitting through the formula for computing evenly bending cut-T section strut bending member’s overall stability coefficient in conjunction with the analysis comparison on various φb computational formulas in pertinent literatures. The stability coefficient simplified formula article suggests can ensure design safety and avoid too conservative determination of stability coefficient value, and is appropriate for the calculation of stability bearing capacity out-of-plane of truss strut which flange is pressed by bending moment.2、Overall stability bearing capacity of hot-rolled cut-T section struts under different stress conditionsThis study calculates stability bearing capacities of middle flange cut-T section(TM) and narrow flange cut-T section(TN) through standard computing method and ANSYS finite element analysis. The result were compared with that of the experimental result obtained before. It is concluded that, buckling load of shear center loading is greater than that of centroid loading in elastic stage, which is suitable for ideal struts. However for T-struts with defect such as fabrication error, load eccentricity and residual stress, when moving the compression force from the centroid axis to the shear center axis, buckling load of centroid loading is greater than that of shear center loading. In the T-section steel truss design, moving the compression force action line from the centroidal axis to the shear center axis will cause errors in design and insufficient stability bearing capacity of truss members. Project planners should pay attention to this point.