Pouyan PressJournal of Soft Computing in Civil Engineering2588-28722220180401Reliability Analysis of Structures Using Modified FA_PSO Algorithm891015614410.22115/scce.2018.114034.1045ENHamidreza Shahmoradi QomiPh.D. Student, Faculty of Civil Engineering, Semnan University, Semnan, IranPavlo VoitenkoPh.D. Candidate, Graduate Research Assistant, Department of Civil Engineering, Auburn University, Auburn, United StatesMajid TaheriPh.D. Student, Faculty of Civil Engineering, Semnan University, Semnan, IranJournal Article20180108Designing buildings with a very high safety factor is one of the main purposes of a civil engineer. Since in the structural design process, there are several no-confidence; we cannot achieve a perfect safe design. In these cases, we face amount of the probability of failure. So the theory of reliability used to assess the uncertainty. This theoretical for expression the safety of a system uses the reliability index, so it can be said that the calculation of reliability index is an important part of the theory. By the theory of structural reliability, uncertainties arising from the nature of the statistical parameters can be written mathematical equations and considerations of safety and performance of the structure into the design process. Since classical methods are not capable of solving complex functions, metaheuristic algorithms used. In fact, a metaheuristic algorithm is a set of concepts, which significantly able to solve many complex issues, which they can reach an optimal solution in a short time. In this paper, the particle swarm algorithm combined with Firefly and to assess the reliability theory has been used. Reliability index is calculated by searching the shortest distance between the origin and the closed point of Limit State Surface in the Standard normalized space.Mathematical and engineering studies on the issues indicated; Hybrid Firefly and particle swarm algorithm are with great accuracy and speed.http://www.jsoftcivil.com/article_56144_f0cee50ff42acdfe7b214aef94a04a3a.pdf