Graduation Year


Document Type




Degree Name

MS in Civil Engineering (M.S.C.E.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Rajan Sen, Ph.D.

Co-Major Professor

Gray Mullins, Ph.D.

Committee Member

Alberto Sagüés, Ph.D.


FRP, GFRP, Destructive Testing, NDT Testing


The Friendship Trail Bridge connecting Tampa to St. Petersburg was demolished in 2016. Thirteen 20 inches. by 20 inches. reinforced concrete piles supporting its superstructure were part of research studies conducted between 2004 and 2008 to explore the role of glass fiber reinforced polymers (GFRP) in corrosion repair. During demolition, piles were typically cut at the pile cap and in the splash zone. The resulting segments varied in length between 3 to 4 ft. These remnants were transported to the University of South Florida (USF) campus for postmortem analysis. The overarching goal was to establish the role of GFRP in reducing the corrosion rate in steel.

Eight piles were selected for the postmortem study. Two were unrepaired controls. Of the remaining six, one was wrapped in 2004, two in 2006 and three in 2008. Except for the 2004 repair that had six glass layers, all piles had two glass layers extending over the entire pile segment that had been retrieved.

The piles were left outdoors at USF and postmortem studies initiated in March 2018. Following delamination and spall survey, the glass fiber wraps were carefully removed, and non-destructive studies initiated. They consisted of half-cell potential measurements, resistivity measurements, and cover-depth measurement using ground penetrating radar (GPR). Subsequently, chloride samples were extracted from the pile cap along lengths of 1 ft and 3 ft at five different depths to the rebar in accordance with ASTM C1152 to determine the total chloride content. The segments were then destroyed, and eight bars retrieved from each of the eight piles. The profile of each of the 64 bars were measured in 120-degree directions along the circumference at every 5 inches using a digital caliper. Metal loss was calculated at each measured location and the highest loss was in one of the controls at 9.2%. Losses were generally below 5%. This was because the chloride concentration at the level of the rebar was below the critical threshold.