This paper describes research by the British Ceramic Research Association into the strength of modern vitrified clay pipes on minimum beddings. It is mainly concerned with examining the need for the present strict specifications for class "D" trimmed trench bottom: line contact bedding. After setting out the theoretical considerations, the authors give an account of three series of trials that they made both in the laboratory and in the field. Results showed that settlements on sand varied with material, moisture content and particle size distribution, and on the hardness of clay. Load ratios for pipes supported on rubber bearers, hard clay, dried unfired bricks and flat fired bricks were found to accord with the theoretical equation for a critical gap of 20-25 per cent of the pipe length, whereas results on sand beds gave no indication of a critical gap length. The authors continue by setting out present regulations relating to minimum beddings together with tables of proposed lower limits for trimmed bottoms, untrimmed bottoms, sand heaps and granular material. Suggested bedding factors are also given. The authors discuss design and economic considerations and conclude with details of a suggested method for laying pipes so as to achieve the appropriate bedding factors. /TRRL/

  • Corporate Authors:

    Institution of Public Health Engineers

    32 Eccleston Square
    London,   England 
  • Authors:
    • BLAND, CEG
    • Ricken, R N
  • Publication Date: 1973-4

Media Info

  • Features: Figures; Tables;
  • Pagination: p. 200-224
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00128132
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Apr 21 1976 12:00AM