Date of Graduation

12-2017

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

Prinz, Gary S.

Committee Member

Hale, W. Micah

Second Committee Member

Riveros, Guillermo

Keywords

CFRP; Fatigue; Lockgate; Mitigation; Pre-Stress; Retrofit

Abstract

Lock gates are an important part of the transportation infrastructure within the United States (US), having many economic, safety, and environmental benefits over rail and highway transportation systems. Unfortunately, many existing lock gates throughout the US have reached or exceeded their initial design life and require frequent repairs to remain in service. Unscheduled repairs often increase as gates age, having a local economic impact on freight transport which can create economic ripples throughout the nation. Fatigue and corrosion are key causes of unscheduled service interruptions, degrading lock gate components over time. Additionally, because lock gates are submerged during operation, crack detection prior to component failure can be difficult, and repair costs can be high.

This thesis presents an analytical and experimental investigation into fatigue damage within common lock gate geometries, and develops fatigue mitigation strategies capable of extending gate service-life. The goal of the research program is to identify critical fatigue regions and locally extend gate component fatigue life. Detailed finite element analyses are combined with fatigue and fracture mechanics theories to predict critical fatigue regions within common gate details and develop retrofit strategies for mitigating fatigue cracking. Full-scale experimental fatigue testing of a critical lock gate component is conducted to provide a baseline for evaluation of retrofit strategies. Retrofit strategies using carbon fiber reinforced polymer (CFRP) plates having optimized pre-stress levels are discussed.

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