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The Scientific World Journal
Volume 2014, Article ID 456826, 9 pages
Research Article

An Efficient Approach to Obtain Optimal Load Factors for Structural Design

Institute of Engineering, Universidad Nacional Autonoma de Mexico, Coyoacan, 04510 Mexico City, DF, Mexico

Received 8 May 2014; Accepted 27 June 2014; Published 15 July 2014

Academic Editor: Joseph Assaad

Copyright © 2014 Juan Bojórquez and Sonia E. Ruiz. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


An efficient optimization approach is described to calibrate load factors used for designing of structures. The load factors are calibrated so that the structural reliability index is as close as possible to a target reliability value. The optimization procedure is applied to find optimal load factors for designing of structures in accordance with the new version of the Mexico City Building Code (RCDF). For this aim, the combination of factors corresponding to dead load plus live load is considered. The optimal combination is based on a parametric numerical analysis of several reinforced concrete elements, which are designed using different load factor values. The Monte Carlo simulation technique is used. The formulation is applied to different failure modes: flexure, shear, torsion, and compression plus bending of short and slender reinforced concrete elements. Finally, the structural reliability corresponding to the optimal load combination proposed here is compared with that corresponding to the load combination recommended by the current Mexico City Building Code.