Optimum design of three-dimensional steel frames with prismatic and non-prismatic elements

In the present article, optimal seismic design of three-dimensional steel frames is carried out. The frames are subjected to gravity and earthquake loadings and are designed according to the LRFD-AISC design criteria. Here, ordinary moment frames are considered having lateral resisting systems. Two types of frames consisting of prismatic frames and non-prismatic frames are optimized and results are compared. Stresses of the elements and drift of the stories are limited in accordance with the AISC-LRFD. Analysis of the frames is performed by utilizing the response spectrum analysis (RSA) method. Three metaheuristic algorithms are utilized for optimizing the example 1, and the most competent algorithm is identified, and the remaining examples are optimized using the identified algorithm. The results of the optimization show lower weight for the non-prismatic frames compared to their prismatic counterparts.