EFFECTS OF CONCENTRATED PRESTRESSING FORCES IN BOX GIRDERS

EFFETS DES FORCES DE PRECONTRAINTE CONCENTREES DANS LES POUTRES CAISSONS

This theoretical and experimental study deals with the anchorage of a prestressing cable in a reinforced concrete slab with free edges by means of backsetting. Mention is made of the fact that, if problems of anchorage at the butt joints of beams and of anchorage systems sunk in a slab have been widely investigated, backsetting Anchorage has not been sufficiently analyzed. This arrangement creates an operational mechanical disymmetry and gives a three-dimensional aspect to the problem. A test was carried out on a concrete slab with an anchorage system in the middle. Results show that backsetting markedly reduces tensile stresses behind the anchorage and improves the distribution of the prestressing force. Three theoretical approaches are outlined. The first is an adaptation of the method developed by Schleeh for the case of a submerged anchorage. It enables the average stresses in the slab to be correctly calculated. The second, based on the method of the cuts which separate the backsetting from the two adjoining slabs, enables the stresses in the slab to be calculated taking account of flexural effects. The 3rd method uses a three-dimensional finite element technique; it gives additional data on the stresses in the backsetting. In the conclusion, details are given of simple reinforcement arrangements with a view to ensuring the correct design of the anchorage zone in the case of the slab with free edges. /TRRL/

  • Availability:
  • Corporate Authors:

    Central Laboratory of Bridges & Highways, France

    75732 Paris,   France 
  • Authors:
    • Lyviere
  • Publication Date: 1977-9

Language

  • French

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00184072
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Research Report 68 Monograph
  • Files: ITRD, TRIS
  • Created Date: Jan 13 1979 12:00AM