Use of Computers in Transmission Tower Design

A computer program for the design and analysis of steel transmission towers or general trusses is presented. Successive iterations between analysis and design, with a tolerance controlled by the designer, are performed within the program to achieve convergence to the final solution. The program capabilities consist of: (1) Generating symmetric portions of geometry; (2) identifying and stabilizing planar (unbraced) nodes; (3) handling tension only members; (4) accounting for the buckling of members by using a bilinear force-displacement relationship; and (5) varying some key nodes to optimize the tower geometry. The redistribution of force due to buckling is achieved by modifying the force matrix only. The buckling and post-buckling behavior is similar to the actual behavior of such members in the transmission towers. The frontal equation solver with an automatic numbering skill has made the program more efficient.