OTIMIZAÇÃO SIMULTÂNEA DO CUSTO E DA CONSTRUTIBILIDADE DE PILARES EM CONCRETO ARMADO

Resumo

Structural design, in general, consists of an iterative process developed with base on the
intuition and previous experience of the designer. This strategy makes the design exhaustive and
makes difficult to obtain the best solution. In addition, usually only one design criterion is adopted,
being usually cost or weight. If other issues are considered, such as the environmental impact or
construction facility, a more complex problem need to be solved. In such context, the aim of this work
is to present the development and implementation of a formulation for obtaining optimal sections of
reinforced concrete columns subjected to uniaxial flexural compression, taking as objectives the
minimization of the cost and the maximization of the constructability. The constraints of the problem
are based on the verification of strength proposed by the Brazilian code ABNT NBR 6118/2014. To
the optimization of the column section, Simulated Annealing optimization method was adopted, in
which the amount and diameters of the reinforcement bars and the dimensions of the columns cross
sections were considered as discrete variables. The total cost is composed of the cost of steel bars,
concrete, and formworks, and the maximization of constructability is obtained by minimizing the total
number of steel bars. The optimized sections were compared to those obtained considering only the
cost as the objective function. To the example considered, it was observed that a significant reduction
of the number of steel bars can be achieved with a small increase on the section cost.