Complementary Condition Assessment of Bridge Decks by High-Frequency Ground-Penetrating Radar and Impact Echo

Accurate assessment of the condition of bridges leads to their economic management. Ground penetrating radar (GPR) and ultrasonic seismic methods, impact echo (IE) in particular, can be successfully used for this purpose by evaluating changes in material characteristics and detection of development of defects and zones of deterioration. One of the most common problems in concrete bridge decks is corrosion induced deck delamination. The current practice of deck inspection by chain dragging or hammer sounding is, with respect to early detection, of limited value. The assessment by chain dragging or hammer sounding is significantly compromised by the fact that those identify delamination at stages where the deterioration has already progressed to such an extent that major rehabilitation is needed. GPR and IE successfully overcome the limitations of those techniques in the ability to detect early signs of bridge deck deterioration and delamination, and the ability to quantify the degree of deterioration. The current practice of GPR bridge deck condition assessment is based on identification of deteriorated sections of the deck from the attenuation of radar reflections from the top layer of rebar. While typical bridge deck delaminations are not visible in GPR scans, the higher the attenuation, the higher is the potential for deck delamination. On the other hand, IE does not provide much information about the material deterioration, but it enables detection of delaminations as reflectors within a bridge deck. Results of a comparative study of application of three high frequency GPR antennas are presented. The antennas used in this study included: a 2GHz air coupled (horn) antenna, a new 2.6 GHz ground coupled antenna, and a lower 1.5GHz ground coupled antenna. While the ground coupled antennas provide higher vertical (time) resolution, the three antennas provide similar condition assessment of bridge decks based on the signal attenuation. GPR attenuation maps are also compared to the IE condition assessment maps, demonstrating benefits of complementary use of GPR and IE bridge deck evaluation and monitoring.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Gucunski, Nenad
  • Rascoe, Carl
  • Parrillo, Robert
  • Roberts, Roger L
• Conference:
  • Transportation Research Board 88th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2009-1-11 to 2009-1-15
• Date: 2009

Language

• English

Media Info

• Media Type: DVD
• Features: Figures; Maps; Photos; References;
• Pagination: 14p
• Monograph Title: TRB 88th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

• TRT Terms: Bridge decks; Condition surveys; Delamination; Deterioration; Ground penetrating radar; High frequency; Inspection; Ultrasonic detectors
• Candidate Terms: Impact echo tests
• Uncontrolled Terms: Bridge inspection
• Subject Areas: Bridges and other structures; Highways; Maintenance and Preservation; I61: Equipment and Maintenance Methods;

Filing Info

• Accession Number: 01128720
• Record Type: Publication
• Report/Paper Numbers: 09-1282
• Files: TRIS, TRB
• Created Date: May 19 2009 7:48AM