Semester

Fall

Date of Graduation

2021

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Hota GangaRao

Committee Member

John Quaranta

Committee Member

Ruifeng Liang

Abstract

Sheet piles consist of numerous interlocked segments that form temporary or permanent support walls and serve as the primary foundational component across a variety of civil infrastructural applications, such as below-grade parking structures or sea walls. The installation of sheet piles is particularly advantageous in coastal areas, as dewatering of the site is unnecessary. Steel is commonly used for sheet piles due to its strength and ease of manufacturing; however, in the presence of saltwater steel begins to rust. Contrary to steel and concrete, fiber reinforced polymer (FRP) composite sheet piles are resistant to chlorides and have considerably higher corrosion resistance. However, varying mechanical properties of FRP composite sheet piles in length and width direction as well as stress risers at the corners of the corrugations cause the soil-structure interaction to be a challenging design issue.

The purpose of this study is to develop a standardized test procedure to determine moment capacity of composite sheet piles. Specifically, the moment incurred at any given point on a sheet pile is proportional to the stress experienced in conjunction(interaction) with soil pressures and a function of failure mode. Testing is conducted using an MTS actuator or winch that is connected to 1 inch diameter threaded rods centered on a wale section that is attached to the sheet pile components at its top. The pile is fixed at the bottom with a sand-concrete mixture of ~70 psi compressive strength (shear strength of ~35 psi) that extends to a height of 3 feet, while the free-standing section of the sheet pile extends an additional 10 feet above mud line. Strain gages and LVDTs are installed strategically on pile surface at both the above and below mud line to monitor its condition during testing and to collect data to establish load vs strain response.

This report concludes that failure occurs along the weak axis of the sheet pile when flexural stress is incurred on the test specimen. A net pressure distribution diagram is created using strain data obtained in laboratory testing and compared with diagrams shown in literature. The diagrams indicate pressure along the depth of the sheet pile, which is used to determine the bending moment. Several sheet piles have been tested with consistent results that correlate well with theoretical sheet pile design calculations. The results from each test were also compared with field test data and are found to correlate well. Results from this study suggest that this test can become a useful resource for engineers and will assist in designing the most economically feasible and structurally efficient sheet pile structure. The test procedure developed herein will be a basis to propose ASTM test procedure to establish load capacity of sheet piles as a function of soil properties and embedment length.

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