Study On Stablity Capacity Of Q460 High-strength Steel Single-Angle Compression Members

High-strength angle steel has been widely used in transmission towers because of their excellent high yield strength, constructional suitability and economy. To study the application of Q460 high-strength hot-rolled equal-leg single-angle in the design of transmission tower, according to three kinds of connection forms about leg members in transmission tower, design-ed 48 single-angle axial compression members,48 single-angle compression members with a concentric load at one end and normal framing eccentricity at the other end, and 48 single-angle compression members attached by one leg. A total of 144 compression members were tested under static loading to investigate failure process, bearing capacity, deformation performance and strain distribution of high-strength angle steel when having with different section types, different slenderness ratios and different end supports. For further theoretical analysis and engineering design proposals provide the basis test material.The experiment result showed most of the small slenderness members were controlled by local buckling, and the large ones were controlled by overall buckling. The greater the slenderness ratio, the higher the test value than the theoretical value, using the existing standard design high-strength angle compression members will be more secure. The larger width-thickness ratios, the greater impact to torsion effect of middle section of the small slenderness members. Axial compression test can use double knife-edge bearing to instead spherical hinge bearing; for the single-angle with an eccentric load at one end and normal framing eccentricity at the other end, the axial laod end can use double knife-edge bearing or spherical hinge beraing; for single-angle steel struts connected by one leg, the experiment result shows'Guide for design of transmission tower'(ASCE10-1997) by American Society of Civil Engineers considered favorable constraint effort at end of members. Comprehensive three-dimensional finite element models were presented for test specimens using the ANSYS11.0 nonlinear finite element program. The material nonlinearity, geometric nonlinearity and contact nonlinearity were considered when simulation analysis. The deformation modes, the ultimate bearing capacity, the influence of slenderness on torsion angle, the influence of width-thickness ratio on bearing capacity and the influence of residual stress were investigated. FEM results were agree well with the experimental results, The residual stesses affected the ultimate load-carring capacity by about 5%.The new stability factor curve models were proposed based on experimental study and simulation analysis, according to the formula of stability factor to establish appropriate design method. By parameter analysis, the stability capacity practical formula on designing Q460 high-strength angle steel compression members. Comparison between the proposed formulas and experimental data demonstrated that they can accurately predict the stability capacity of compression members, which showed these methods are feasible.These experimental and theoretical results about Q460 high-strength angle compression members can guide engineering design or research reference.