Ninety-seven concrete deck structures (282 spans) in Michigan were surveyed by using a pachometer to determine the average depth and variation of the concrete cover. Fifteen structures (36 spans) were surveyed by using the wet-depth method. It is believed that, if the clear-cover target value is increased to 7.62 cm (3.0in) (and no attempt is made to control process variation), fewer than 3 percent of the structures will have less than 5.08 cm (2.0in)of clear cover over more than 10 percent of their surface area. Increases in the cover specification have had no measurable effect on the mean span variation. For most structures, the distribution of measurements for individual spans is consistent with approximately 95 percent of the measurements within 1.9 cm (0.75in) of the average value. Wet-depth measurements do not compare favorably with pachometer measurements and, in more than 50 percent of the spans, the mean difference between the two methods was greater than 0.64 cm (0.25in). to adequately determine the depth of concrete cover, 100 measurements/span or one measurement for each 2.32 sq m (25 sq ft), whichever is less, should be taken. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; Tables;
  • Pagination: pp 36-41
  • Monograph Title: Bridge design, evaluation, and repair
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00195912
  • Record Type: Publication
  • ISBN: 0309028191
  • Files: TRIS, TRB
  • Created Date: Aug 15 1979 12:00AM