Date of Award

May 2019

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Civil and Environmental Engineering


Riyad S. Aboutaha

Subject Categories



Precast-prestressed concrete (PC) girders are among the most cost-effective type of girders used on highway bridges. Unfortunately, in corrosive environments, corrosion of strands may result in cracking or spalling of concrete, cross-section loss of strands and degradation of material properties, which in turn reduces the load-carrying capacity of PC bridges.

This research presents an in-depth analysis of residual flexural strength of corroded AASHTO Type II pretensioned PC girders with a cast-in-place (CIP) concrete deck. The investigation involved development of a detailed Finite Element Analysis (FEA) model of the pretensioned girder-deck system subjected to corrosion. The FEA model developed for this research considered bond deterioration between corroded strands and surrounding concrete, deterioration of material properties and cross-section loss of corroded strands. The FEA model was verified against experimental data from relevant research studies and showed good agreement. Over three hundred pretensioned concrete girder-deck systems were investigated with the developed FEA model. Several design parameters were considered: 1) span-depth ratio, 2) prestressing reinforcement ratio, 3) corrosion level, 4) number of corroded strands, and 5) corrosion length. Results from the FEA model were used to develop a detailed analytical model to study the residual flexural strength of the girder-deck system. Then, the analytical model was applied to study the impact of those five parameters listed above on the residual flexural strength of investigated girder-deck systems.

It was concluded that corrosion of prestressing strands significantly influenced the failure mode and load-bearing capacity of pretensioned PC girder-deck systems. When corrosion level was lower or equal to 7.5%, the girder-deck system failed by crushing of the concrete in the compression zone. For a corrosion level higher or equal to 12.5%, the girder-deck system exhibited a rupture failure of prestressing strands. The girder-deck system that was corroded to a mass loss between 7.5% and 12.5% failed either by crushing of the concrete or strand rupture, depending on parameters such as span-depth ratio, prestressing reinforcement ratio, number of corroded strands, and corrosion length.

When a corroded pretensioned girder-deck system failed by crushing of the concrete, the decrease in flexural capacity was affected mainly by the number of corroded strands and corrosion levels. Impacts of corrosion length, span-depth ratio and prestressing reinforcement ratio on the strength reduction were negligible. When a corroded pretensioned girder-deck system failed by strand rupture, the impact of corrosion length on the strength reduction should also be considered.

Finally, a simplified practical model has been developed to estimate the residual flexural strength of corroded pretensioned girder-deck systems. The simplified model was tested against the data of analytical and FEA models, and showed good agreement.


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