MECHANISM OF ANCHORAGE AND DISTRIBUTION OF THE PRESTRESSING FORCE IN CONCRETE BEAMS PRESTRESSED BY PRETENSIONING

MECANISME D'ANCRAGE ET DIFFUSION DE LA FORCE DE PRECONTRAINTE DANS LES POUTRES EN BETON PRECONTRAINT PAR FILS ADHERENTS.

PRETENSIONING IS WIDELY USED TODAY ALTHOUGH THERE EXISTS NO ACCURATE KNOWLEDGE OF HOW PRESTRESSING OCCURS AND IS DISTRIBUTED THROUGH THE CONCRETE. AN EXPERIMENTAL INVESTIGATION IS DESCRIBED INTO THE AUTOMATION OF RELAXATION AND MEASUREMENT OPERATIONS. THIS OFFERED THE POSSIBILITY OF CONTINUOUSLY OBSERVING THE CONDITIONS OF THE BEAMS DURING PRESTRESSING AND OF STUDYING SOME ASPECTS OF DEFORMED BARS. HOWEVER, IN SPITE OF THE RESULTS OBTAINED THE ANCHORAGE MECHANISM IN PRESTRESSING BY PRETENSIONED THE EXPERIMENTAL INVESTIGATION IS NOT SUFFICIENT TO GIVE A COMPLETE PICTURE OF THE CONDITIONS OF THE CONCRETE IN THE IMMEDIATE VICINITY OF THE REINFORCEMENT WHERE PLASTIFYING AND FISSURATION PHENOMENA CAN OCCUR AND AFFECT THE ANCHORAGE OF THE REINFORCEMENT. IT WAS ENVISAGED TO USE THE FINITE ELEMENT METHOD TO OBTAIN A SATISFACTORY KNOWLEDGE OF STRESSES IN CONCRETE. UNFORTUNATELY THE BOUNDARY CONDITIONS OF THE PART OF THE CONCRETE IN CONTACT WITH THE REINFORCEMENT ARE UNKNOWN. THEY CAN HOWEVER BE DETERMINED EXPERIMENTALLY BY EXTENSOMETER MEASUREMENTS. TWO CASES USING THIS TECHNIQUE ARE DESCUSSED. IN THE FIRST CASE, THE CONCRETE IS ASSUMED TO BE ELASTIC. IN THE SECOND, IT IS ASSUMED TO BE AN ELASTO-PLASTIC MEDIUM FULFILLING A PLASTICITY CRITERION JUDICIOUSLY SELECTED. THE CALCULATIONS MADE IN BOTH HYPOTHESES GIVE SOME INFORMATION ON THE FORMATION OF A PLASTIFIED CONCRETE LAYER AT A SHALLOW DEPTH IN THE PROXIMITY OF THE REINFORCEMENT. THE EFFECT OF THIS PLASTIFYING MECHANISM ON STRESSES AND DEFORMATION SEEMS IMPORTANT; IT MAINLY AFFECTS THE CIRCUMFERENTIAL AND LONGITUDINAL STRESS VALUES.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/04585860
• Authors:
  • ATALLAH, R
  • HAKAKIAN, K
  • BONNET, A
  • BRACHET, M
• Publication Date: 1975-3

Language

• French

Media Info

• Pagination: 65-80
• Serial:
  • BULL LIAISON LAB PONTS CHAUSS
  • Issue Number: 76
  • ISSN: 0458-5860

Subject/Index Terms

• TRT Terms: Anchorages; Beams; Calculation; Concrete; Deformation; Elasticity (Mechanics); Finite element method; Measurement; Physical distribution; Plasticity; Prestressed concrete; Pretensioning; Strain gages; Stresses; Tests
• ITRD Terms: 3420: Anchorage; 3472: Beam; 6464: Calculation; 4755: Concrete; 5595: Deformation; 9016: Distribution (gen); 5912: Elasticity; 6490: Finite element method; 6136: Measurement; 5922: Plasticity; 4796: Prestressed concrete; 4798: Pretensioning; REINFORCEMENT (I.E. CONCRETE) ; 5562: Strain gauge; 5575: Stress (in material); 6255: Test
• Subject Areas: Construction; Freight Transportation; Materials; I32: Concrete;

Filing Info

• Accession Number: 01307044
• Record Type: Publication
• Source Agency: Institut Francais des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)
• Files: ITRD
• Created Date: Nov 21 2010 11:04AM