Author ORCID Identifier

https://orcid.org/0009-0004-1540-7564

Semester

Spring

Date of Graduation

2024

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

James Bryce

Committee Member

Onur Avci

Abstract

The development of press-brake-formed tub girders (PBFTGs) has offered innovative solutions for short-span steel bridge applications and helps meet the demand for rapid infrastructure replacement solutions. The Short Span Steel Bridge Alliance (SSSBA) comprises bridge and buried soil structure industry leaders who aim to provide essential educational information to bridge and highway professionals on the design and construction of short-span steel bridge installations (SSSBA, 2020). The American Association of State and Highway Transportation Officials (AASHTO) provides design standards, specifications, and guidance for the analysis and construction of PBFTGs. Currently, the AASHTO Load Resistance and Factor Design Bridge Design Specifications (AASHTO LRFD BDS) classifies PBFTGs as noncompact sections under any skew angle, which places a limit on the flexural capacity to the yield moment (My). This specification greatly limits the applicability of PBFTGs in bridge design, as the plastic moment capacity (Mp) cannot be achieved when designing a PBFTG bridge using the current AASHTO LRFD BDS.

The scope of this research project was to better understand and characterize the flexural behavior of PBFTGs under low-skew angles to expand the applicability of the PBFTG system. This project was performed in four stages. Experimental pseudo-static flexural testing was first performed on two composite 15-degree PBFTGs to collect data and observe the ultimate capacity of each system. 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 benchmark against the experimental test data. A sensitivity study was developed by modeling a matrix of 3,509 PBFTG bridges using the three-dimensional finite element modeling software Abaqus. Girders were modeled with varied parameters before analyzing the impact of each parameter on the ultimate flexural capacities. The analysis specifically was employed to further verify that skewness does not impact the ultimate flexural capacity and that the behavior can be considered compact for PBFTGs with skew angles up to 20 degrees.

Results of this research project show that low-skewed PBFTGs perform with an ultimate flexural resistance exceeding the first yielding moment. This study demonstrates that PBFTGs have a more comprehensive range of applicability and can be a strong competitor in the bridge market if the AASHTO LRFD BDS adopts the recommendation to classify PBFTGs with skews up to 20 degrees as compact sections. Integrating this concept will broaden the applicability of PBFTGs and benefit the design process of shallow steel tub girder bridges.

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