The importance of special tests to optimize or check design assumptions and to pinpoint practical considerations relating to construction and stressing is emphasized. The monitoring of the overall anchor rock structure system is discussed, and comments are made on the service behavior of production anchors. The special tests may be summarized as dynamic and static tests. The former class of tests which involve progressive and continual loading of the anchor until failure is induced, provide data on the ultimate capacity of certain elements e.g. grout/tendon bond or rock/grout bond. Static tests involving load time relationships are determined to investigate the anchorage effectiveness. Basic tests used to ascertain the suitability of any ground anchor system (temporary or permanent) in Germany are described. In France, the basic test anchors are categorized by geometry and ground type, and the minimum number of test anchors is related to the number of production anchors in one category. Monitoring of the behavior of the structure, rock mass and anchors, individually or in groups, facilitates study of the short and long term interaction between different components of the complete system. The long-term behavior of rock anchors in service is discussed with reference to the load-retaining characteristics of anchors for periods in excess of 24 hours after final stressing. Information relating to the relaxation and creep properties of steel tendons is presented, and some case histories are assembled to illustrate the importance of the phenomena causing load loss. It is recommended that each anchor should be subjected to an initial proof loading stage, and attention is drawn to the possible conflicts between new design concepts and existing code recommendations.

  • Availability:
  • Corporate Authors:

    Ground Engineering

    7 Ongar Road
    Brentwood CM15 9AU,   England 

    Foundation Publications Limited

    7 Ongar Road
    Brentwood CM15 9AU, Essex,   England 

    Wells (Edward) and Sons, Limited

    143/145 Camberwell New Road
    London SE5,   England 
  • Authors:
    • Littejohn, G S
    • Bruce, D A
  • Publication Date: 1976-5

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 8 p.
  • Serial:
    • Volume: 9
    • Issue Number: 4
    • ISSN: 0017-4653

Subject/Index Terms

Filing Info

  • Accession Number: 00141090
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 6 1976 12:00AM