PROBLEMS OF HIGH STRENGTH BOLTED CONNECTIONS IN STEEL CONSTRUCTION. EFFECTS OF WEATHERING ON THE COEFFICIENTS OF FRICTION OF UNPROTECTED AND PROTECTED FAYING SURFACES

In slip-proof connections of steel structural elements by means of high-strength bolts, the transfer of forces depends, inter alia, upon the coefficient of friction between the faying surfaces. Previous tests carried out in the context of Question D 90 have investigated the effect upon the coefficient of friction of different methods of preparation and protection of the faying surfaces. This report describes tests designed to investigate the effects of exposing the faying surfaces to weathering before assembly. Grit-blasted and flame-cleaned surfaces, with and without protective coatings, were exposed for periods of three to five months in industrial and marine atmospheres. After assembly, the values of the coefficient of friction were determined under short-term static loading. The results obtained indicate that weathering, either industrial or marine, may in some cases significantly alter the coefficient of friction. With grit-blasted unprotected faying surfaces, the mean value of the coefficient of friction is reduced by exposure in an industrial environment, but virtually unaffected by exposure in a marine environment. With flame-cleaned unprotected faying surfaces which were flame-cleaned again after exposure, a noticeable increase in the coefficient of friction was found. In the case of unprotected faying surfaces, the effect of the different methods used for the first cleaning (prior to weathering) is however generally nullified by three months' exposure. Further tests would be required to confirm that the additional expense of flame-cleaning after exposure, instead of the cheaper cleaning with an appropriate brush, is justified.

• Supplemental Notes:
  • Restrictions on the use of this document are contained in the explanatory material.
• Corporate Authors:

  International Union of Railways

  Office of Research and Experiments
  Utrecht,   Netherlands 
• Publication Date: 1968-10

Media Info

• Features: Figures; Tables;
• Pagination: 22 p.

Subject/Index Terms

• TRT Terms: Corrosion protection; Protective coatings; Tests; Weathering
• Old TRIS Terms: Question d90
• Subject Areas: Construction; Railroads;

Filing Info

• Accession Number: 00052899
• Record Type: Publication
• Source Agency: International Union of Railways
• Report/Paper Numbers: D90/RP 3/E
• Files: TRIS
• Created Date: Nov 17 1976 12:00AM