The economy of design is a crucial factor in all engineering disciplines. In prestressed concrete structures, it is a challenge and a matter of competition among the engineers to lessen the weight of the structures and reach an optimum design. In the present work, a design procedure incorporating the generalized reduced gradient (GRG) method is used for optimization of prestressed concrete simple beams. The objective function is chosen to be the total materials’ cost of the structure, subject to strength and serviceability requirements as per the latest Egyptian Code Specifications. The basic design variables categorized into continuous and discrete variables. The continuous variables are the cross sectional-dimensions and the amount of prestressing steel. The discrete variables are steel and concrete strengths. The design constraints are strength in bending, strength in shear, ductility, minimum amounts of longitudinal and shear reinforcements, and deflection. Three examples of fully prestressed simple beams are presented to demonstrate the efficiency of the optimization technique. Different starting points are tested for each example. The obtained results show the accuracy and robustness of the technique. |
