Non-linear analysis on steel transmission tower using beam-column method

Abstract

For reflecting the actual working of the tower transmission, requirements about analysis model and review during processes used in the design must be determined and clearly assessed.The non-elastic analysis will directly overcome the disadvantages of methods that were based on linear elastic analysis above-mentioned. Main advantage of this method which based on direct analysis of nonlinear geometric effects and nonlinear materials is: (i) without using coefficientof computed length because nonlinear geometric effects are integrated directly; (ii) the interaction due to plastic flow and gradual instability as per increasing load is taken into account; (iii) to provide results of internal forces of the entire structure with consideration over the internal force redistribution as true status of the system; (iv) to predict the stiffness of the structures transmission tower with a more accuracy; (v) to figure out the nonlinear behavior of the system, order and modes of failure of structures and structural systems, as well as ultimate bearing capacity of the system; (vi)to apply suitably and reasonably all kind of frame structures including unbracing frame, bracing frame and mixed frames.In this paper, following problems have been solved: Beam-column method using stability function with plastic hinged in both ends in order to describe the nonlinear behavior of structural steel transmission tower, then a nonlinear algorithm for analyzing the system subjected to static load was created. A practicable Fortran program for analyzing nonlinear system rigid frame, bracing frames, steel frames and power supply towers was established. After then, the reliability of the developed program has been evaluated and compared to that ofSAP2000 results. Finally, developed programs was used to design electricity transmission towers