Selected Field Results: San Francisco Oakland Bay Bridge Acoustic Emission Monitoring Program

Following the discovery of a significant crack in an eyebar (fracture critical element) on the San Francisco-Oakland Bay Bridge (SFOBB), the California Department of Transportation (Caltrans) explored possible remote monitoring solutions. The design of the structural health monitoring system (SHM) would continuously monitor the entire length of selected eyebars for the earliest possible detection and location of potential cracking in order to provide an additional safeguard for close to 277,000 vehicles crossing the bridge daily. Through a competitive bid, the Acoustic Emission (AE) method was chosen for this remote monitoring system as the most viable solution of available technologies. The SHM system would complement the quarterly inspections performed by Caltrans and assist in monitoring several critical areas that were extremely difficult to inspect. Since early 2012 the system has been on-line and collecting data. This unique project represents the largest known SHM application in which only 640 AE sensors monitor the entire length of 384 eyebars for an approximate total length of 3.94 miles. This paper will discuss field deployment of the AE SHM system and a few of the results from the automated alarm “events” identified by the system. One of the triggered events identified a potential mechanism, which if gone unnoticed, could have resulted in additional damage to key structural elements and a potential repair cost of over $14 million. Including the cost of the AE SHM system, the cost of the repair, including labor and materials was less than 25% of the potential repair cost.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AFF40 Field Testing and Nondestructive Evaluation (NDE) of Transportation Structures.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Johnson, Michael B
  • Gostautas, Richard S
  • Tamutus, Terry A
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References;
• Pagination: 12p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Acoustic emission tests; Detection and identification systems; Fatigue cracking; Nondestructive tests; Remote sensing; Structural health monitoring
• Identifier Terms: California Department of Transportation; San Francisco-Oakland Bay Bridge
• Subject Areas: Bridges and other structures; Highways; Maintenance and Preservation; I60: Maintenance;

Filing Info

• Accession Number: 01515112
• Record Type: Publication
• Report/Paper Numbers: 14-2859
• Files: TRIS, TRB, ATRI
• Created Date: Feb 21 2014 3:16PM