Sustainable Design Optimization of Reinforced Concrete Frames Considering CO2 Emission Minimization

Abstract

Nowadays, the environmental consequences of global warming are of major concern. Worldwide, efforts are being made to reduce the CO2 (carbon dioxide) emissions in order to mitigate the greenhouse effect. Construction sustainability is gaining increasing relevance in the last years to cope with the large environmental impact of construction industry. Considering this the structural design should aim to obtain economical, structurally efficient and “environmentally-friendly” solutions. In this work a numerical model for the sustainable optimum design of reinforced concrete (RC) frames was developed. The structural analysis includes all the actions and relevant effects, namely, dead and live loads, the time-dependent effects and the geometrical nonlinearities. The analytical discrete direct method is used for sensitivity analysis. The sustainable design of RC frames is formulated as a multi-objective optimization problem with objectives of minimum construction cost, minimum CO2 emissions, minimum deflections and stresses and a Pareto solution is sought. The minimax solution is found by the minimization of a convex scalar function obtained through an entropy-based approach. The displacements and stresses design goals are established according to the Eurocode 2 recommendations for the design of framed structures. The design variables considered are the beams and columns cross-sectional dimensions and the steel reinforcement area. The features and applicability of the developed numerical model are demonstrated by a numerical example concerning the optimization of a real sized RC frame.