Optimization of Prestressed Concrete Flat Plates

Abstract

Mathematical programming techniques are used for the solution of a comprehensive optimal design problem formulation. The formulation, based on American codes of practice, includes constraints related to service, ultimate, and collapse limit states, as well as relevant technological constraints. Solutions to the nonlinear programming problem are obtained with an appropriate computer program, OPTIMAL. This is used for solving a wide range of typical flat plate designs with varying span‐to‐depth ratios, live loads, cable layouts, limit states, and allowable tension stresses. A related sensitivity study enables the comparison of optimal and standard solutions based on the following parameters: (1) Rate of equivalent prestressing and total external load; (2) average concrete stress in compression; (3) active design constraints; (4) material costs; (5) dead to total external load ratio; (6) reinforcement index; and (7) partial prestressing ratio. Some areas of possible improvement of current standard procedures are identified.