SHEAR FORCE OPTIMUM REINFORCEMENT IN CONCRETE GIRDERS

L'ARMATURE OPTIMALE D'EFFORT TRANCHANT DANS LES POUTRES EN BETON

THE METHOD PROPOSED IS BASED ON A MODEL OF THE LATTICE BEHAVIOUR OF THE WEB UNDER ULTIMATE STRESS. BASED ON THE ORIGINAL IDEA BY RITTER AND MORSCH BUT GENERALIZED AND COMPLETED WITH THE HELP OF LIMITATIONS AND CORRECTIONS DEVELOPED FROM THE RESULTS OF NUMEROUS TESTS CARRIED OUT OVER HALF A CENTURY. A NEW APPROACH TO THE METHOD OF CONTROL BY SHEAR FORCE (PROPOSED BY THE CEB-FIP STANDARD MODEL) IS THE FREEDOM LEFT TO THE PROJECT ENGINEER TO CHOOSE THE ANGLE OF INCLINATION (T) OF THE CRACKS. THE VALUE OF THIS ANGLE INFLUENCES THE DESIGN OF THE STIRRUPS AND OF THE ADDITIONAL LONGITUDINAL REINFORCEMENT NEEDED BECAUSE OF THE SHEAR FORCE. THOSE TWO STEEL SECTIONS - STIRRUPS AND LONGITUDINAL REINFORCEMENT - EVOLVE IN OPPOSITE DIRECTIONS, EG, IF, COMPARED TO A PREVIOUS CALCULATION, (T) = 45 DEGREES ACCORDING TO THE CONVENTIONAL LATTICE CONCEPT BY MORSCH, THE ANGLE (T) ADOPTED MUST BE MODIFIED SO THAT MORE STEEL GOES INTO THE STIRRUP. THE ADDITIONAL SECTION OF LONGITUDINAL REINFORCEMENT DECREASES. THE QUESTION REMAINS TO KNOW WHETHER AN OPTIMUM ANGLE (T) EXISTS, FOR WHICH THE OVERALL QUANTITY OF STEEL, IN THE FORM OF STIRRUPS AND ADDITIONAL LONGITUDINAL REINFORCEMENT, IS MINIMUM. THIS ARTICLE IS AN ATTEMPT AT SOLVING THIS PROBLEM.

Language

  • French

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 01290170
  • 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 2:06AM