Development and operation of a portable instrument for recording strain events in bridges under field-service conditions are described. The instrument consists of a transducer, which is lamped to the flange of a bridge by four allen screws; a set of mechanical counters driven by electronic logic circuity; a battery pack; and a tamper-proof enclosure. As much as 80 d of continuous operation can be realized before batteries must be serviced. Each counter is incremented every time the strain reaches the triggering level selected for that counter. Triggering levels are selected to be distributed over a range slightly greater than the strain range expected in the bridge. For the usual case, in which the triggering levels are all in the elastic range, a simple hand calculation will produce a stress histogram from the counter readings. The theory and a procedure for predicting bridge life from the collected data are also presented. Results of a short field test indicate that the instrument provides a practical and economical means by which relatively unskilled personnel can collect stress-history data. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 25-29
  • Monograph Title: Bridge tests
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00179378
  • Record Type: Publication
  • ISBN: 0309026741
  • Files: TRIS, TRB
  • Created Date: Aug 27 1978 12:00AM