Optimal Design of Lattice Towers Under Earthquake Loading

Abstract

Two methods are proposed and evaluated for discrete variable optimization of structures subjected earthquake loads. The first method, called the two-phase method, uses a combination of continuous and discrete optimization algorithms and the second one, called an adaptive discrete assignment method (ADAM), uses only a continuous optimization algorithm. The proposed methods are applicable to any discrete variable problem that can be formulated as a continuous problem. A lattice tower is solved to demonstrate the methods. In addition, the problem is solved with a genetic algorithm (GA). Efficiency and practicality of the proposed methods are compared to those of the GA. From the results, it is concluded that GA is a very straightforward method to use for discrete problems; however, it requires a significant amount of CPU time. On the other hand, the two-phase method and ADAM do not require as much computational effort but the discrete designs found with them are more expensive. Also they require more effort for their computer implementation.