A parametric study of optimum earth-retaining walls by simulated annealing

This paper examines the economic optimization of reinforced concrete earth-retaining walls used in road construction. The simulated annealing algorithm is the proposed method to optimize walls. The formulation of the problem includes 20 design variables: four geometrical ones dealing with the thickness of the kerb and the footing, as well as the toe and the heel lengths; four material types; and 12 variables for the reinforcement set-up. The study estimates the relative importance of factors such as the base friction coefficient, the wall-fill friction angle and the limitation of kerb deflections. Finally, the paper presents a parametric study of commonly used walls from 4 to 10 m in height for different fills and bearing conditions. Average expressions are calculated for the total cost, the volume of concrete, the thickness of the kerb and the footing, the lengths of the footing and the heel, which may be useful for the practical design of walls. An upper bound of 50 kg/m3 of reinforcement in the kerb and 60 kg/m3 for the overall wall is reported.