LOSS OF PRESTRESSING FORCE IN POST TENSIONED STRANDS
PERDIDAS EN LA FUERZA DE PRETENSADO EN ELEMENTOS POSTESADOS.
BASED ON THE STUDIES OF GUYON, SOME EXPRESSIONS ARE DEVELOPED FOR CALCULATING THE LOSS OF FORCE IN PRESTRESSING STRANDS. TWO TYPES OF LOSS ARE DISTINGUISHED: INITIAL LOSS WHICH OCCURS DURING TENSIONING OR IMMEDIATELY AFTER ANCHORAGE; AND DEFERRED LOSS WHICH OCCURS DURING THE FIRST TWO OR THREE YEARS. TAKING THE FIRST CASE, THE LOSSES DUE TO FRICTION ARE ANALYSED: FRICTION IN THE JACK, AT THE ANCHOR BLOCK OUTLET, INSIDE THE SLEEVES AND CONDUITS, AND THOSE DUE TO PARASITE EFFECTS; FRICTION DUE TO DEFORMATION OF THE ANCHORAGE, TO POSSIBLE SLIPPING OF REINFORCEMENT, OR TO NON-SIMULTANEOUS STRETCHING WHICH CAUSES THE DEFORMATION OF SOME CABLES AS SUBSEQUENT ONES ARE TENSIONED. IN THE SECOND CASE SOME OF THE CONTRIBUTING FACTORS ARE CONCRETE SHRINKAGE, RELAXATION OF THE STEEL (ABOUT 8 TO 10% OF THE ORIGINAL TENSION), AND THE CREEP OF THE CONCRETE. THESE THREE CAUSES ARE SIMULTANEOUS AND THE RESULTANT STRESS LOSS IS AFFECTED BY FACTORS WHICH DEPEND ON THE TENSION-DEFORMATION DIAGRAM OF THE STEEL AND LAWS OF THE CREEP OF THE CONCRETE. AN APPLIED EXAMPLE IS GIVEN.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/00201022
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Authors:
- POGGIO, M A
- Publication Date: 1974-3
Language
- Spanish
Media Info
- Pagination: 105-30
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Serial:
- ING CIV (CUBA)
- Volume: 25
- Issue Number: 2
- ISSN: 0020-1022
Subject/Index Terms
- TRT Terms: Anchorages; Calculation; Concrete; Creep; Deformation; Friction; Jacks (Mechanical equipment); Loss and damage; Mechanical relaxation; Modulus of elasticity; Posttensioning; Shrinkage; Stresses; Time
- ITRD Terms: 3420: Anchorage; 6464: Calculation; 4755: Concrete; 4732: Creep (mater); 5595: Deformation; 5452: Friction; 3831: Jack; 9040: Loss; 5919: Modulus of elasticity; 4789: Post tensioning; REINFORCEMENT (I.E. CONCRETE) ; 5407: Relaxation (mech); 4743: Shrinkage; 5575: Stress (in material); 5414: Time
- Subject Areas: I32: Concrete;
Filing Info
- Accession Number: 01298475
- 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 6:46AM