Post tensioned simply supported prestressed concrete (PC) I-girder bridges are
widely used bridge system for short to medium span (20m to 50m) highway bridges due to its moderate self weight, structural efficiency, ease of fabrication, low maintenance etc. In order to compete with steel bridge systems, the design of PC I-girder Bridge system must lead to the most economical use of materials. In this paper, cost optimization approach of a post-tensioned PC I-girder bridge system is presented. The objective is to minimize the total cost in the design process of the bridge system considering the cost of materials, fabrication and installation. For a particular girder span and bridge width, the design variables considered for the cost minimization of the bridge system, are girder spacing, various cross sectional dimensions of the girder, number of strands per tendon, number of tendons, tendons configuration, slab thickness and ordinary reinforcement for deck slab and girder.