The need for joints in high yield ribbed reinforcement used in reinforced concrete and their requirements are examined. The relative merits of joints made by welding and the use of sleeves are discussed. The method of threading the ends of the bars to be joined and running them into a coupler is described in detail. The parent bar is cold threaded using hardened steel dies. This process work hardens its surface raising the proof strength locally producing threads with greater strength than cut threads. Three methods of taking up the clearance between the bar and the coupler threads before loading are given. Fatigue testing has been carried out on 50 mm ribbed bars with a Whitworth thread. Elongation testing on the three types of joints is also described. Resin infilling between the threads gave the most consistently low elongation values. Extension tests have been carried out on 25 mm, 32 mm and 40 mm bars with optimum size threads. Although the concrete cover usually gives adequate corrosion protection, other forms of protection are discussed. Recent contracts using coupled joints include the Humber Bridge, the Ninian Oil Platform and the Gatwick Airport Terminal Building. /TRRL/

  • Availability:
  • Corporate Authors:

    Cement and Concrete Association

    Wexham Spring
    Slough SL3 6PL, Buckinghamshire,   England 
  • Authors:
    • Wright, M S
  • Publication Date: 1978-3

Media Info

  • Features: Photos;
  • Pagination: p. 32-34
  • Serial:
    • Volume: 12
    • Issue Number: 3
    • ISSN: 0010-5317

Subject/Index Terms

Filing Info

  • Accession Number: 00182665
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Dec 29 1978 12:00AM