This paper is concerned with the possibility of using very high strength steels (with a 0.2 per cent proof stress of 750 to 1000 n/square metre) as reinforcement in concrete. The author points out that cp100 limits steel to a value of 460n/square metre because of the serviceability problem (excessive crack widths and deflections) with higher strength steels. Prestressing overcomes the problem but is difficult to carry out with in-situ concrete in multi-storey structures. The use of a mixture of normal reinforcing steel with high strength steel is discussed. The concept is that the low strength steel will be used near its full strength capacity and the very high strength steel take over to provide additional strength beyond the working load, providing the safety margin against collapse. In this area excessive cracking and deflection are said to be of no concern to the designer. The author outlines the basis of design calculations which employ the ultimate resistance moment using the cp110 strain compatability method in the analysis of a reinforced concrete T-Beam as used in multi-storey structures, and illustrates it with a worked example. Comments are made on the economics of the use of very high strength steel where its cost would depend on demand. Mention is made of how the proposed system would allow the use of the mild steel component as a steel channel forming the soffit of the beam (the high strengh steel being within the channel) which would facilitate construction, because their low depth (as compared with i-shaped joists) would allow the use of transverse pre-cast units or low cost permanent shuttering. /TRRL/

  • Availability:
  • Corporate Authors:

    Cement and Concrete Association

    52 Grosvenor Gardens
    London SW1W 0AQ,   England 
  • Authors:
    • TAYLOR, R K
  • Publication Date: 1975-7

Media Info

  • Features: Figures;
  • Pagination: p. 35-36
  • Serial:
    • Volume: 9
    • Issue Number: 7
    • ISSN: 0010-5317

Subject/Index Terms

Filing Info

  • Accession Number: 00128304
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Apr 7 1976 12:00AM