Flexural Behavior Degradation of Corroded Aashto Type II Pretensioned Concrete Girder-Deck System

Abstract

Precast-prestressed concrete (PC) girders are among the most cost-effective type of girders used on highway bridges. Compared with conventional reinforced concrete bridges, PC bridges have higher load-carrying capacity and better crack control. Unfortunately, in corrosive environment, corrosion of strands may result in cracking or spalling of concrete, cross-section loss of strands and degradation of material properties, which affect the flexural behavior of PC bridges. PC bridges are more susceptible to corrosion damage since the bond between prestressing strands and concrete is vital to transfer prestressing force and prestressing strand normally experiences a higher stress level. However, study on the flexural behavior of corroded prestressed concrete girders are very limited. This paper presents an in-depth analysis of flexural behavior of corroded AASHTO Type II pretensioned PC girders with a cast-in-place (CIP) concrete deck using finite element analysis (FEA). The FEA model developed considered bond deterioration between corroded strands and surrounding concrete, deterioration of material properties and cross-section loss of corroded strands. Over three hundred pretensioned concrete girder-deck systems were investigated using the developed FEA model. The following parameters were the primary variables: (1) span-depth ratio, (2) prestressing reinforcement ratio, (3) corrosion level, (4) number of corroded strands, and (5) corrosion length. Failure modes, residual flexural strength, and ductility were analysed for each FEA model. It was concluded that corrosion of prestressing strands significantly influenced the failure mode, residual flexural strength, and ductility of pretensioned concrete girder-deck systems. Corrosion level and number of corroded strands have major impacts on the remaining load-carrying capacity of the corroded system.