Optimized design of concrete-filled steel columns

Abstract

The objective of this paper is to present the formulation of the optimization problem and its application to the design of concrete-filled composite columns with and without reinforcement steel bars, according to recommendations from NBR 8800:2008, NBR 16239:2013 and EN 1994-1-1:2004. A comparative analysis between the aforementioned standards is performed for various geometries considering cost, efficiency and materials in order to verify which parameters influence the solution of the composite column that satisfies the proposed problems. The solution of the optimization problem is obtained by using the genetic algorithm method featured in MATLAB’s guide toolbox. For the examples analyzed, results show that concretes with compressive strength greater than 50MPa directly influence the solution of the problem regarding cost and resistance to normal forces.

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“…Genetic algorithms have proven to be very effective in these optimizations. Among different works using GA, we can mention: Breda, Pietralonga, and Alves [6] composite floor system; Lourenção et al [7] Tubular composite columns filled with concrete; Liu, Hammad, and Itoh [8] and Cho, Min, and Lee [9] who proposed the optimization for recovery and life cycle assessment of bridges, respectively, to reduce structural recovery costs and minimize the degree of deterioration of the work; Kuan-Chen Fu, Zhai, and Zhou [10]; Kociecki and Adeli [11] , Prendes-Gero et al [12] and Kripakaran, Hall, and Grupta [13] spatial steel frames; Papavasileiou and Charmpis [14] optimized the cost of composite steel and concrete beams and columns intended for multi-story buildings built in regions prone to earthquakes. In addition to GA, another evolutionary algorithm that stands out is the Particle Swarm Optimization (PSO), initially proposed by Kennedy and Eberhart [15], with variable applications in structural engineering, as can be highlighted in the works of the following authors:…”

“…The constraint group 𝐺 J = {𝐶(1), 𝐶(2), 𝐶(3), 𝐶(4), 𝐶(5)}, formed by equations 10 to 14 has a very similar form to the group 𝐺 ! = {𝐶(6), 𝐶 (7), 𝐶(8), 𝐶(9), 𝐶(10)}, formed by equations 15 to 18. The constraints of these groups represent, respectively: the web slenderness limitation, the degree of interaction, the ultimate limit state (ULS) for bending, ULS for shear, ELS of permissible deflection.…”