Author ORCID Identifier

https://orcid.org/0000-0002-3138-4604

Semester

Fall

Date of Graduation

2023

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Karl Barth

Committee Member

Gregory Michaelson

Committee Member

Onur Avci

Committee Member

Dimitra Pyrialakou

Abstract

Press-brake-formed tub girders (PBFTGs) offer innovative solutions for short-span steel bridge applications, possessing efficiency, versatility, and sustainability. These girders are galvanized shallow trapezoidal boxes fabricated from cold-bent structural steel plates. Depending on the design requirements, a concrete deck or other deck options, such as a steel sandwich plate system, can be placed on the girders. The Short Span Steel Bridge Alliance (SSSBA) extensively researched the steel PBFTG bridge system. As a testament to its potential, the AASHTO Innovation Initiative (AII) recognized it as a 2021 Focus Technology. AII has shown commitment to promoting the adoption of PBFTG among its member associations, local agencies, and industry partners, aiming to enhance the U.S. infrastructure. Given the growing recognition and support from industry leaders and organizations, PBFTGs are poised to be crucial in addressing the U.S. infrastructure challenges.

This project aims to improve the design and analysis of PBFTGs regarding live load distribution factor (LLDF) prediction. Field testing performed on PBFTG bridges showed that the empirical equations found in the American Association of State Highway and Transportation Officials’ Load and Resistance Factor Design Bridge Design Specifications (AASHTO LRFD BDS) are conservative when used for PBFTG bridges. Hence, there is a potential for improving and refining the AASHTO LRFD BDS provisions related to PBFTGs and their LLDFs. The live load distribution behavior of a matrix of 207,696 PBFTG bridges with varied parameters was analyzed using three-dimensional finite element analysis. From the analysis result, statistical models were employed to produce simplified and enhanced empirical equations that can better predict live load moment distribution in PBFTGs. The prediction power and accuracy of the simplified equations were assessed using a comprehensive statistical analysis. In addition, the impact of the improved LLDF predictions was examined by using design feasibility and applicability to commercially available shallow steel tub girder bridges, contrasting the AASHTO LRFD BDS's empirical formulas against the newly proposed ones.

This study demonstrated that the developed equations significantly improve the prediction of live load distribution of PBFTGs from a statistical perspective. Hence, they are recommended for adoption in AASHTO LRFD BDS. Integrating these proposed equations can substantially streamline the design process for shallow steel tub girder bridges, broadening their applicability.

Embargo Reason

Publication Pending

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Available for download on Friday, December 06, 2024

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