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Iowa State University--Becoming the Best

Buchanan County IBRD Bridge Project: Evaluation of a Folded Plate Girder Bridge System


Principal investigators:

Project status


Start date: 03/01/13
End date: 06/30/17


Report: Evaluation of a Folded Plate Girder Bridge System (11.45 mb pdf) June 2017

Tech transfer summary: Evaluation of a Folded Plate Girder Bridge System (673.63 kb pdf) Jun 2017



About the research


With the assistance of the Iowa Department of Transportation (DOT) and the Institute for Transportation (InTrans) at Iowa State University, Buchanan County, Iowa was awarded a Federal Highway Administration (FHWA) Innovative Bridge Research and Deployment (IBRD) Program grant to help construct and evaluate an innovative short-span bridge (i.e., the Amish Sawmill Bridge). The bridge was designed and constructed using folded plate tub girders.

This bridge utilizes a folded plate girder superstructure supported on geosynthetic-reinforced soil (GRS) abutments. To evaluate the structural behavior of the bridge, the researchers conducted laboratory and field testing with the goal of validating the adequacy of the folded plate girder for short-span bridge construction.

The research team conducted three laboratory tests on a folded plate girder specimen similar to the girders that were used on the completed bridge to study the girder’s construction-stage behavior, flexural behavior, and shear behavior. The researchers conducted live load field tests immediately after completion of the bridge with the girders and one year after bridge construction to evaluate the behavior of the bridge and its components. Full-scale finite element models of the bridge were established to interpret the test results. The researchers drew the following conclusions from experimental and numerical evaluation results: