Title: Evaluation of In Service Reinforced Concrete Box Culverts through Diagnostic Load Testing and Refined Analysis

Author(s): Amir Gheitasi

Publication: Web Session

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Date: 10/17/2021

Abstract:
According to the Texas Department of Transportation (TxDOT) Inventory, there are more than 19,000 reinforced concrete box culverts in service. The majority of these culverts have been carrying unrestricted traffic for many years with no significant signs of structural distress or deteriorations. However, recent load rating analysis of a select population of these culverts indicated insufficient capacity in carrying design and legal loads, which would trigger posting requirements as well as traffic restrictions. WSP USA was tasked with comprehensive performance evaluation, including load testing and refined analysis, to improve the load ratings of forty representative in-service culverts. The select culverts were in different districts across the state and deemed to be representative of the state’s broad culvert inventory, covering a wide range of geometrical configurations, material properties, design loads, and design standards. Diagnostic load testing was conducted on ten out of the forty culverts to valuate in-service performance and gain a better understanding of the actual load distribution behavior (i.e., load attenuation) in this class of culverts. The results of load testing were then used to calibrate a series of full 3D Finite Element (FE) models including the effects of soil-structure interaction. Calibrated 3D FE models were leveraged to adjust key assumptions and attributes in a series 2D FE models for load rating purposes on all forty culverts. This paper describes details of load testing and FE modeling to refine the load ratings of the select forty culverts. Results from this investigation indicated significant improvement in load ratings of the evaluated culverts in the presence of more realistic modeling and consideration of soil-structure interaction and its impacts on live load distribution behavior of reinforced concrete box culverts.