Seismic pre-dimensioning of irregular concrete frame structures: Mathematical formulation and implementation of a learn-heuristic algorithm

Irregular frame structures can exhibit an inefficient dynamic behavior, such as undesirable torsional effects and asymmetric displacements, that can severely affect structural performances in case of a seismic event. To mitigate the influence of geometric irregularities, the predimensioning of structural elements is crucial to achieve the best possible seismic behavior. Identifying the optimal solutions in terms of elements' cross-sections and orientations is a non-trivial problem that in general designers tackle following trial-and-error attempts which can become numerous in the most complicated cases. This paper formally describes the pre-dimensioning problem and presents a Learn-heuristic that hybridizes a Genetic Algorithm and a k-Means algorithm procedure for its solution. The algorithm is validated on a diverse set of 3D reinforced concrete structures and through a Structural Pre-dimensioning challenge, where the performances of the algorithm are compared against those accomplished by a group of Ph.D. candidates. The computational results evidenced that the proposed optimization framework achieves pre-dimensioning solutions that significantly improve the designs provided by the Ph.D. students, thus suggesting a favorable inclusion of the proposed solution method in classical pre-dimensioning processes.

Automated summary

The study discusses the pre-dimensioning problem and presents a hybrid algorithm for its solution, which significantly improves design efficiency compared to traditional methods.