Study On The Stability Of Large Limb Width Of High-strength Equilateral Angle Steel

With the continuous development of high voltage transmission line towers, high-strength angle has been widely used. High strength angle can alleviate the complicated joint structure and make lighter installation, which also reduces the consumption and investment in transmission tower structures. Recent years, many studies on the stability of high-strength angle have been carried out in China. However, the research on stability for the large limb width of high-strength angle is scarce. In order to meet the demands of the current project, the overall stability and local stability of 300mm limb Q420 structural steel are studied both theoretically and experimentally. The main research results are as follows:(1) L300 × 30 and L300× 35 two specifications were carried out under axial compressive load. The classification of 300mm limb width equal angle steel section take as an A-level by comparing the analysied test results and the relevant specification. The instability of the shape and angle stable bearing capacity were discussed. The morphology of instability around the minor axis is bending instability. The stress and strain of the middle position are the largest.(2)L300×20 and L300×24 two specifications were analyzed with the finite element analysis software. Combined with the overall stability factor, a simple and practical formula of stability is put forward. The formula provides a reasonable and reliable design method for engineering application and research.(3) Axial compression test of L300×20 and L300x24 two specifications were carried out. Bearing capacity and failure mode of the overrun width to thickness ratio component were discussed. The unstable form of the width to thickness ratio is local instability, and the damage position of the component depends on the slenderness ratio.(4) The 26 angle steel stability of L300x20 and L300x24 two specifications were analyzed with the finite element analysis software, combined with strength reduction factor of overhead line tower design technology of electric regulation, the results were summarized and analyzed, we can know the different strength reduction factor and standard 300mm wide limb member in the strength reduction factor. For L300 x 20 and L300 × 24 specifications of the angle, strength reduction factor in the slenderness ratio of less than 60 is a decreasing trend, slenderness ratio greater than 60, the strength reduction factor increments.