APPLICATION OF NSGA-II TO DESIGN MULTIPLE MITIGATION DEVICES IN SLENDER STRUCTURES

In this paper, the multi-objective evolutionary algorithm, Non Dominated Sorting Genetic Algorithm (NSGA-II), is applied to solve the design of passive mitigation devices, commonly referred to as Tuned Mass Dampers (TMD). A common challenge is obtaining a set of optimal Pareto Points, evenly distributed along the Pareto Front. Two usual states are used as objective functions to articulate the multi-objective optimization procedure. The Serviceability Limit States (SLS, objective number 1) can be evaluated through the accelerance frequency response functions and the Ultimate Limit States (ULS, objective number 2) is considered by evaluating the drift between storeys when undergoing, for example, a particular earthquake. The results have shown that NSGA-II is able to obtain the Pareto Front, indicating the TMD or TMDs to install, considering those two objective functions, under the condition that the mass of the TMDs to be put is bounded.