Graduation Year

2020

Document Type

Thesis

Degree

M.S.C.E.

Degree Name

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

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Gray Mullins, Ph.D.

Committee Member

Michael J. Stokes, Ph.D.

Committee Member

Christopher L. Alexander, Ph.D.

Keywords

Concrete, Prestress, Splash Zones, Strain, Marine, Lateral Capacity

Abstract

Of the 12,741 bridges accounted for by the Florida Department of Transportation (FDOT), approximately 50% were built between the 1950s and 1960s. During this period, bridges were typically constructed in coastal environments using pile bents. Now, the main threat to bridges in these environments is corrosion, which occurs in the splash zones of most bridge piles. These zones contain high concentrations of chlorides, oxygen and moisture, the corner stones of a highly corrosive environment. Corrosion compromises steel reinforcement in these areas leading to cracking, spalling and an inevitable loss of capacity.

In recent years, significant strides have been made in the development of bridge maintenance criteria, repair methods and materials to combat this problem. One set of materials typically used in corrosion mitigation are carbon fiber reinforced polymers (CFRP). These materials are high-strength and extremely durable and are now used as added protection for structures even before corrosion is apparent. CFRPs have been found to supply resistance of axial loads on a structure by resisting expansion however the lateral capacity benefits of this material have not been fully investigated.

This study utilizes CFRP wrap to repair one-third scaled bridge piles corroded over 20 years. Preliminary investigations concluded that all lateral capacity of the piles was lost since no viable steel reinforcement was found in the corroded sections. A repair method was then derived based on a modelled repair using simulated CFRP wrap. Piles were then repaired with CFRP wrapping according to the repair method outlined by the model and used to construct a one-third scaled bridge bent for a lateral capacity test. Results indicate that CFRP repair regains all lateral capacity lost due to corrosion.

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