LOSS OF BOLT TENSION IN STEEL BRIDGES

Tension in each of sixty 7/8" diameter A-325 structural steel bolts was monitored for a period of 45 days. Primary variables were paint treatments on the clamped plates before insertion of the bolts and tightening method. Two types of red lead and an inorganic zinc paint were applied in varying thicknesses. Both the calibrated-impact-wrench and turn-of-the-nut methods of tightening were used. In bolts tightened by the turn-of-the-nut method, initial tensions were higher and more uniform than in those tightened by the calibrated-impact-wrench method, and could therefore tolerate greater losses without falling below the minimum specified tension. /FHWA/

• Record URL:
  https://spexternal.modot.mo.gov/sites/cm/CORDT/MCHRP77-2.pdf
• 
• Supplemental Notes:
  • Sponsored by the Missouri State Highway Department. Prepared in cooperation with DOT and FHWA.
• Corporate Authors:

  University of Missouri, Columbia

  Department of Civil Engineering, 2509 Engineering Building East
  Columbia, MO  United States  65211
• Authors:
  • Baldwin Jr, J W
  • Murphy, D D
• Publication Date: 1978-1

Media Info

• Pagination: 52 p.

Subject/Index Terms

• TRT Terms: Bolts; Lead (Metal); Metal bridges; Paint; Steel bridges; Tension; Zinc rich paint
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00178823
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: FHWA-RD-78-S0730 Final Rpt., FCP 45F2-442
• Files: TRIS, USDOT
• Created Date: Sep 14 1978 12:00AM