Date of Award

Summer 8-23-2019

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Department

Civil Engineering

Advisor

William Davids

Second Committee Member

Roberto Lopez-Anido

Third Committee Member

Warda Ashraf

Abstract

Reinforced concrete is a widely used structural system in conventional construction. It is used to create beams, columns, slabs, walls, bridge decks, dams, and many other structures. Concrete is a relatively inexpensive material that is much stronger in compression than in tension. This leads to the need to combine concrete with other materials to make an efficient hybrid structure. In conventional construction, steel reinforcing bars (rebar) are often used to carry the tension in the structure, as they are widely available and their design is well understood. There are some situations where rebar is not effective such as highly corrosive environments. A continuous fiber-reinforced thermoplastic (CFRTP) panel could be used as non-corrosive tension reinforcement in concrete structures to replace steel rebar. In this research, three sets of composite CFRTP-concrete specimens were designed, manufactured, and tested to evaluate their use as a replacement for steel rebar in reinforced concrete construction. To function as the tension reinforcement for the structure, a shear connection mechanism was needed to create composite action between the CFRTP panel and the concrete. For this research, E-glass fiber-reinforced thermoplastic polyethylene terephthalate glycol (PETg) was selected for its good mechanical and hygro-thermal properties and relatively low cost compared to other thermoplastic composites. Each

set of composite CFRTP-concrete beams was designed to meet the requirements for a bridge deck with stay-in-place formwork given in the AASHTO LRFD Bridge Design Specifications. The first set of specimens consisted of a flat CFRTP panel with friction welded thermoplastic shear studs as the shear transfer mechanism. When loaded in four-point bending, the specimens failed at the CFRTP-concrete interface at a load that corresponded to about 50% of the ultimate strength of the shear connection from stud testing. For the second and third iterations of testing, modifications were made to the CFRTP panels to increase their flexural stiffness, allowing them to function as stay-in-place formwork for the structure. This would reduce installation costs and times as formwork and shoring would not need to be erected or removed. The second set of specimens consisted of a corrugated CFRTP panel with steel dowels run through the webs as a shear transfer mechanism. The corrugations were created by stamp forming a flat panel in a mold. The corrugated hybrid beams were tested in four-point bending and reached 117% of the required design loading prior to failure. The final set of specimens consisted of a stiffened CFRTP panel where holes were cut into the stiffeners, allowing concrete to flow into the holes creating a concrete dowel that would bear directly onto the CFRTP to transfer shear. The stiffened panels were created by bonding angle- shaped CFRTP panels to a flat CFRTP panel. The stiffened hybrid beams were tested in four-point bending and reach around 128% of the required design loading prior to failure.

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