Concrete structures

me sive tim rosi lev lifetime-oriented design the amount and location of the steel reinforcement and the value of the concrete cover play a crucial role for the optimal achievement of the desired lifetime structural performance. 2009 Elsevier Ltd. All rights reserved. res un on sim itions., water limit t Based on these premises, life-cycle approaches to structural optimization of deteriorating systems have been proposed to high-light the fundamental role played by the time-variant performance in the optimal maintenance planning and selection of the optimum structural design [1–13]. Reliability-based life-cycle optimization approaches to deteriorating RC structures have been reported in a Monte Carlo simulation. The role played by a lifetime approach to structural optimization is shown by comparing the optimal solu-tions obtained with a classical time-invariant formulation, which considers the initial undamaged state only, and the proposed life-time formulation, where the time evolution of the structural per-formance is taken into account. The obtained results show that in a lifetime-oriented design the minimum feasible area of rein-forcement is not associated with the maximum depth of the steel bars over the concrete cross-section, as expected in a classical time-invariant approach, but the amount and location of the rein-forcement and the value of the concrete cover play a crucial role