The web system of the regular trian

The web system of the regular triangular section arm adopts a herringbone layout, and the trolley luffing mechanism is easy to process and arrange. The web members are triangular. For the triangular structure, the upper chord is made of round steel pipe, and the lower chord is welded by angle steel, which is also used as the running track of the trolley. The truss can be regarded as a cantilever beam on the plane of rotation, bearing the lateral load. The upper chord of the inverted triangle structure is usually round steel pipe, and the I-beam of the bottom chord is also used as the running track of the trolley. The root of the boom is connected with the tower body through a pin, and the boom is provided with a lifting point, which is connected to the top of the tower cap by a steel wire rope or a steel tie rod. In order to facilitate the installation, transportation and composition of booms of different lengths, the boom is generally divided into several sections, consisting of a root section, an end section and several standard sections, and each section is connected by bolts and pins.Truss-type horizontal booms mostly use equilateral triangular cross-sections, so here we choose equilateral triangular cross-sections as shown in Figure a.