Date of Award

4-2019

Document Type

Thesis - Open Access

Degree Name

Master of Science in Civil Engineering

Department

Civil Engineering

Committee Chair

Jeff Brown, Ph.D.

First Committee Member

Ashok H. Gurjar, Ph.D.

Second Committee Member

Dan Su, Ph.D.

Abstract

In 2012, the federal government estimated that $17.5 billion was spent on inspection, rehabilitation, maintenance, and replacement of the nation’s bridges. While the average lifespan of steel and reinforced concrete bridges is 50 years, certain bridges subjected to extremely aggressive marine environments may not reach this desired target. This research paper investigates using fiber-reinforced polymer (FRP) materials as primary bridge girders in medium span bridges (30 ft. to 75 ft.). The goal of this research is to identify the most efficient and cost-effective alternative for these corrosion-resistant materials and potentially extend the lifespan of these bridges up to 75 years. Three distinct profiles were investigated in this research: U-shaped, concrete-filled FRP tubes, and Double Web I-Beams (DWB). Finite Element Modeling (FEM) was used to study the overall stiffness of FRP girder bridges with a cast-in-place concrete deck. Girder distribution factors for moment were also computed using reliability analysis tools and FEM. These results were then compared to existing AASHTO methods. Once the most efficient cross-section was identified (U-shaped girder), a preliminary study investigating the vacuum infusion manufacturing process was conducted to verify that the required thicknesses of FRP can be achieved. Simple bending tests were completed on small-scale FRP beams to demonstrate the strength capacity and evaluate any difficulties using the vacuum infusion process (VIP). The results in this research study conclude that the U-shaped bridge girder is the most cost-effective alternative, yet fabrication remains challenging and complicated.

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