Otimização de escadas de concreto armado baseada em confiabilidade dependente do tempo.

Abstract

Reinforced concrete structures are often subject to deleterious effects of an uncertain nature that change over time. Which are generally considered based on deterministic analyses, not taking into account their random behaviors. Given the possibility of structural failure resulting from the action of these effects, it is relevant to consider them in structural reliability problems as time-dependent random variables (stochastic process). Furthermore, it is already common practice in a structural engineer's day-to-day life to use optimization techniques, which provide safe and economical projects. The present research aims to develop optimization routines in Matlab for the design of reinforced concrete stairs, based on time-dependent reliability. Initially, a routine for calculating the time-dependent probability of failure was developed, using the Monte Carlo Simulation method and the Autoregressive Moving Average (ARMA) time series model. After, the Particle Swarm Optimization (PSO) metaheuristic optimization algorithm was coupled. The routines presented satisfactory results, given that in the problem addressed, all restrictions were respected, especially the 10% threshold for probability of failure. Obtaining a cost of R$ 1,979.00, referring to the steel and concrete used in the stairs. Which ensures the economy and reliability of the structure.