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Project Information
Project ID:   FHWA-PROJ-11-0108
Project Name:   Characterizing Unknown Foundations to Improve Bridge Safety
Project Status:   Active
Start Date:  April 2, 2012
End Date:  January 31, 2014
Contact Information
Last Name:  Jalinoos
First Name:  Frank
Telephone:  202-493-3082
E-mail:  frank.jalinoos@dot.gov
Office:   Office of Infrastructure Research and Development
Team:   Hazard Mitigation Team [HRDI-50]
Program:   IRT (Infrastructure Research and Technology)
Laboratory:   J. Sterling Jones Hydraulics Laboratory
Project detail
Roadmap/Focus area(s):   Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:   The unknown bridge foundations issue remains one of the most persistent problems facing the bridge engineering community. The National Cooperative Highway Research Program (NCHRP) Project 21-5 devoted considerable effort in developing new test methods to address this issue and some good progress was reported (Olson et al., 1996). However, there are still concerns on the reliability of the available technologies and associated costs, especially when they require the drilling of a borehole adjacent to the foundation. This activity would develop a multiyear research program to solve the Nation’s unknown foundations problem and increase bridge safety. Innovations to be further pursued include identification that could lead to characterizing bridges with unknown foundations in terms of foundation type, material(s), depth, and integrity. One or more workshops will be conducted to identify approaches, reaching out to groups within and outside the normal bridge community. The product of these workshops will be a report detailing the best approaches to be taken and a plan of action to resolve this issue. The centerpiece of this program could be a full-scale outdoor laboratory to develop, test, and validate new and existing technologies for effective characterization of unknown foundations. Technologies to be developed, enhanced, and evaluated could include, but not be limited to, acoustic/seismic, electrical, magnetic, and radar.  The exact nature of the program will be determined after receiving input from workshop participants.
Goals:  
The key project objective of this research is to develop a multiyear research program to solve the Nation’s unknown foundations problem. The goal is to evaluate new and existing technologies for characterizing bridges with unknown foundations in terms of foundation type, material(s), depth, and integrity. 
Background Information:   As of December 2010, the National Bridge Inventory (NBI) includes 473,628 bridges and 130,827 culverts (i.e. 604,455 total structures) with a span greater than 20 ft (6 m). Of those structures, 502,698 have the service under the bridge coded as waterway or a combination that includes a waterway. For a large number of older non-Federal-aid highway bridges (i.e. those on local roads or rural minor collectors), and to a lesser extent Federal-aid highway bridges, as-built plans are not available. Currently, 59,658 bridges over waterways (riverine and tidal) in the NBI database are identified as having unknown foundation characteristics. The number of bridges in the NBI database that are coded "U" under Item 113 (for “unknown foundations”) have been reduced considerably over the years. In 1996, 104,000 were quoted in the National Cooperative Highway Research Program (NCHRP) Research Results Digest 213; in 2001, 89,000 were quoted in the Federal Highway Administration (FHWA) Hydraulic Engineering Circular (HEC) No. 18; in 2005, 86,000 bridges were quoted at the Denver’s “Unknown Foundation Summit”; and, in 2007, the NBI database identified 67,002 bridges. The main reasons for this reduction can be attributed to efforts by each State Department of Transportation (DOT) in finding the lost plans, conducting field nondestructive evaluations, and performing risk-based assessments such as that recommended in NCHRP Document 107 (Stein and Sedmera, 2006), or the recent 2009 FHWA memorandum.
Product Type:   Article
Research report
Techbrief
Technical report
Test Methodology:   Through a broad agency announcement (BAA), multiple studies would be conducted to identify economical methods to address unknown foundation characteristics. These studies would result in products and/or methodologies for further development and field trails.
Expected Benefits:   Not having the above foundation information exposes bridge owners and the public to unnecessary risk. Following the catastrophic collapse of the Schoharie Creek Bridge on the New York State Thruway in April 1987, national attention has been focused on the bridge scour problem. Foundation characteristics are needed for accurate scour analysis, which was nonexistent for the Schoharie Creek Bridge. Therefore, as a result of addressing scour vulnerability of bridges, the unknown foundation also became a national priority.
Deliverables:   Workshop/meetings.
FHWA Topics:   Roads and Bridges--Hydraulics
TRT Terms:   Bridge Foundations
Scour
Types of Bridges
Infrastructure
Research
Bridges
FHWA Disciplines:   Hydraulics
Geotechnical
Subject Areas:   Hydraulics and Hydrology
Geotechnology
Bridges and other structures
Design

 

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