Anchorage of Large-Diameter Reinforcing Bars in Ducts

One method of connecting a column to a cap beam in bridge bents is to precast the column with projecting bars, which are then grouted into ducts in the cap beam. Bar-duct systems can be assembled rapidly if a few large bars and ducts are used to connect the column and cap beam. However, the required anchorage lengths for the large bars can exceed the length available. This study evaluates the anchorage requirements for this situation by performing 14 pullout tests on bars with sizes up to No. 18. The tests and a nonlinear finite element model showed that, under conditions similar to those tested, large bars can develop their yield strength in as few as six bar diameters and fracture strengths in as few as 10 bar diameters. In all the tests, failure occurred either by formation of a cone near the grout surface combined with shearing along the confined bar-grout interface or by bar fracture. The specimens did not fail by duct pullout or concrete splitting. Polypropylene fiber reinforcement typically lowered the peak pullout strength of the bar and had mixed impact on the post-peak response.

  • Availability:
  • Authors:
    • Steuck, Kyle P
    • Eberhard, Marc O
    • Stanton, John F
  • Publication Date: 2009-7


  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 01141728
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 11 2009 8:48PM