Structural Analysis and Optimization of Dissipative Steel Frame Structures

Damages incurred by structures during seismic events and the associated elevated post-seismic repair costs led to the development of capacity design which ensures that seismic energy is dissipated through specific parts of the structure undergoing plastic mechanisms while other parts remain elastic. Fuse-like elements have been proposed over the last few decades as devices capable of dissipating earthquake energy and granting seismic resilience to structures during strong earthquakes. Existing studies propose innovative steel brace systems equipped with dissipative links which have proven their effectiveness through experimental and numerical analyses in the existing literature. The study presented here investigates the sensitivity of the dissipated hysteresis energy to parameters like geometry variations, strength distributions, and position of knee elements to optimize the seismic performance of these types of structures. The optimization of this steel structure equipped with dissipative links is accomplished using numerical models developed with OpenSees and a genetic algorithm (GA) executed with the appropriate objective function. The sensitive parameters to the dissipator element and the overall structure are determined after each seismic response of the case study structures and considered as individual genes. The methodology employed involves the randomized generation of a population within a predefined range of variation, and the evolution of this population through crossover and mutation until the appropriate performancestopping criteria is reached. The results demonstrate that GA can efficiently generate optimal parameter distributions satisfying seismic performance requirements which can be evaluated in terms of structural response and hysteresis energy dissipation.