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Title: Field Testing and Refined Load Rating of a Concrete Pan Girder Bridge

Author(s): Nuzhat Kabir, Tevfik Terzioglu, Mary Beth D. Hueste, Stefan Hurlebaus, John B. Mander, Stephanie G. Paal

Publication: Symposium Paper

Volume: 352


Appears on pages(s): 135-154

Keywords: bridges, concrete pan girders, finite element method, live load distribution factors, load rating, load testing

DOI: 10.14359/51734861

Date: 5/31/2022


Load rating procedures can include conservative assumptions, which may result in load posting bridges that have sufficient load carrying capacity. This study investigated the accuracy of live load distribution factors (LLDFs) and potential refinements to the load rating process for simple span concrete pan girder bridges. A typical load-posted simple-span concrete pan girder bridge, without as-built drawings, was selected as a representative case study. The behavior of the bridge, including live load distribution, was studied through finite element method (FEM) modeling and field testing. The results obtained from the field tests were used to calibrate the FEM model. The FEM model captured the measured distribution of loads across the bridge width with reasonable accuracy. The AASHTO Manual for Bridge Evaluation provides guidelines for load rating bridges using Load and Resistance Factor Rating, Load Factor Rating, and Allowable Stress Rating. The AASHTO Standard Specifications LLDFs for interior girders were found to be slightly conservative, while those in the AASHTO LRFD Specifications were quite conservative. Although the impact on load rating for this particular bridge was found to be relatively small, the verified modeling approach provides useful guidance for load rating similar bridges using refined analysis.