Semester

Fall

Date of Graduation

2025

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Onur Avci

Committee Member

Greg Michaelson

Committee Member

James Bryce

Abstract

The Short Span Steel Bridge Alliance (SSSBA) is a group of bridge and buried soil steel structure industry leaders who have joined together to provide educational information on the design and construction of short span steel bridges in installations up to 140 feet in length. Press-brake-formed-tub-girders (PBFTGs) were developed by a technical working group within the SSSBA in response to a rising demand for rapid infrastructure replacements for short span bridge applications. PBFTGs are produced from structural steel plate and can be finished as weathering steel or galvanized. After being cold bent to the appropriate shape, shear studs are welded onto the top flanges. The PBFTG system provides numerous concrete deck options. In situations where time is critical, decks can be pre-cast in a fabrication shop and delivered to the jobsite ready to be placed. In other cases, girders can be placed on site where the deck can be cast-in-place.

The scope of this project was to better understand the flexural behavior of PBFTG system at various angles of skew, and in turn, expand the applicability and usability of the PBFTG system. This was performed in four stages. First, a complete understanding of recent PBFTG research was provided. Next, destructive pseudo-static flexural testing was performed on one composite 30º Valmont U18 PBFTG to collect data and observe the flexural behavior of the system. Then, a rational methodology based on previous PBFTG research at West Virginia University (WVU) was used to build analytical, three-dimensional, finite element analysis (FEA) models to serve as a benchmark against the experimental test data. Lastly, a sensitivity study was performed on 406 PBFTG bridge models. More specifically, this study aims to discover, across all varied parameters, at what degree of skew can PBFTGs still be considered compact.

Results of this project demonstrate that skew angels up to 20º do not significantly affect the flexural capacity of PBFTG. Furthermore, this study demonstrates that PBFTG have a larger range of applicability and can be more competitive in the market if the American Association of State and Highway Transportation Officials Load Resistance and Factor Design Bridge Design Specifications (AASHTO LRFD BDS) adopts the recommendation to classify PBFTGs as compact sections up to skew angles of 20º.

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