PMSS Project Details

Project ID:	FHWA-PROJ-11-0039
Project Name:	Radiographic Inspection of Gusset-Plate Connections
Status:	Completed
Contact:	Last Name: Ocel First Name: Justin Telephone: 202-493-3080 E-mail: justin.ocel@dot.gov
Organization:	Federal Highway Administration - Turner-Fairbank Highway Research Center (TFHRC)
Office:	Office of Infrastructure Research and Development
Team:	Bridge and Foundation Engineering Team
Roadmap/Focus area(s):	Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:	The project needs to evaluate existing radiographic inspection technologies and post-processing for inspection of gusset-plated truss connections. The project would have to evaluate and recommend techniques needed to produce effective images through multiple gusset plates, and then demonstrate the ability to determine where different density changes (i.e., corrosion loss) exist. This would include recommendations for radiation intensity, required number of images, required standoff distances, etc. Finally, the technique should be deployable without the need to shut down traffic for radiation concerns if at all possible. This project will run in parallel with the National Cooperative Highway Research Program project (NCHRP 12-84) research and use two of those research specimens on which to test the technique.
Laboratories:	Structures Laboratory
Start Date:	May 9, 2011
End Date:	August 31, 2011
Funding Amount:	$20,000.00
FHWA Program Name:	Innovative Bridge Research and Deployment
Goals:	To determine the efficacy of using radiographic testing (RT) for the inspection of multilayered gusset-plated connections to find corrosion hidden from typical visual inspections.
Project Type:	Onsite
Background Information:	The National Transportation Safety Board (NTSB) outlined five safety issues as part of the I-35W bridge (Minneapolis, MN) collapse investigation. One of the safety issues was the apparent inadequate use of technologies to assess the condition of gusset plates on truss bridges. This applies in particular to the inability for inspectors to quantify section loss on the interior surfaces of gusset plates of congested connections. The National Transportation Safety Board (NTSB) recommended ultrasonic nondestructive evaluation to determine section loss. However, ultrasonic inspection can only reliably determine thickness through one steel plate, though gusset plate connections often utilize multiple layers of thinner steel plates to define the total gusset plate. Radiographic inspection has the ability to perform density measurements through multiple steel plates, and in terms of gusset plate inspection, may be far superior to ultrasonic techniques. Radiographic inspection is not a new technology, but new developments in digital film and computer post-processing of digital images make the technology easier and faster to use effectively. In addition, the inherent shielding of the steel connection itself reduces the standoff distances to where traffic shutdowns would not be necessary.
Test Methodology:	Full-scale experimental.
Other Information:	Data not yet available
Partners:	Data not yet available
More Information URL(s):
Fieldtest:	Data not yet available
Expected Benefits:	Reduced inspection time and more reliable assessment of remaining section in multilayered gusset plates.
Deliverables:	Name: Final report. Product Type(s): Techbrief Description: This report will be written by the contracted agency and will include a description of their radiographic testing inspection method, results attained, and interpretations of the data collected. Audiences: State highway agencies Secondary Audiences: Publication URL(s): http://www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge/12071/
Related URL(s):
Project Findings:	Data not yet available
FHWA Topics:	Roads and Bridges--Asset Management Roads and Bridges--Structures Research/Technologies--Turner-Fairbank Highway Research Center (TFHRC)
TRT Terms:	Radiography Gusset Plates Corrosion Inspection Infrastructure Bridge Trusses
FHWA Disciplines:	Structures
Subject Areas:	Bridges and other structures Research Maintenance and Preservation