Sensitivity analyses of the optimum design parameters of prestressed post-tensioned I-girder and deck-slab system

Abstract

The main objective of this paper is to analyze the sensitivity of the optimum design parameters of a girder-deck system and hence obtain an effective solution. The optimization problem by which optimum values of design parameters are obtained is based on a global optimization algorithm named “Evolutionary Operation”. This problem contains a total of 14 design parameters and bounded by 14 explicit constraints along with 46 implicit constraints. For sensitivity analyses, deviations of these parameters are considered on both the upper and lower sides of the optimum solutions which reflect their realistic possible ranges of deviations. For small deviations, compliance with the explicit and implicit constraints are examined. Characteristics of cost variations are also identified. It is observed that deck slab thickness is the most sensitive parameter in terms of structural adequacy. The approach is applied to a real-life bridge project. The slab thickness parameter in the conventional design procedure is less sensitive compared to optimized slab thickness. Finally, an attempt is taken to obtain an effective solution for optimum design with reduced sensitivity.