FURTHER RESULTS ON THE EQUILIBRIUM METHOD OF LIMIT DESIGN

THE BASIC PRINCIPLES OF THE EQUILIBRIUM (SERVICEABILITY) METHOD OF LIMIT DESIGN FOR REINFORCED CONCRETE STRUCTURES ARE REVIEWED. THE GENERALITY OF THE METHOD IS ILLUSTRATED BY FIVE DIFFERENT APPROACHES TO THE DESIGN OF REINFORCED CONCRETE CONTINUOUS BEAMS. TWO FRD (FULL REDISTRIBUTION DESIGN) APPROACHES TEND TO MAXIMIZE INELASTIC MOMENT REDISTRIBUTION AND THREE OLD (OPTIMUM LIMIT DESIGN) APPROACHES TEND TO MINIMIZE THE MATERIAL CONSUMPTION. THESE APPROACHES ARE APPLIED TO THE DESIGN OF A LARGE NUMBER OF CONTINUOUS BEAMS WITH EQUAL SPANS AND THE SAFETY, SERVICEABILITY AND EFFICIENCY OF RESULTING SOLUTIONS ARE EXAMINED. THE ECONOMY OF A LIMIT DESIGN RELATIVE TO THE ELASTIC DESIGN IS EVALUATED BY AN EFFICIENCY INDEX THAT IS DEFINED AS THE RATIO OF CORRESPONDING FLEXURAL STEEL VOLUMES. THREE TYPES OF OBJECTIVE FUNCTIONS, REFLECTING A VARIETY OF REINFORCEMENT DETAILING PRACTICES, ARE CONSIDERED. THE INFLUENCE OF GEOMETRY, LOADING, TYPE OF OBJECTIVE FUNCTION AND DESIGN APPROACH ON THE EFFICIENCY OF LIMIT DESIGN SOLUTIONS IS STUDIED IN DETAIL. IT IS FOUND THAT FRD AND OLD SOLUTIONS ARE INFLUENCED IN A SIMILAR WAY BY THE ABOVE PARAMETERS, THAT BOTH ACHIEVE FULL REDISTRIBUTION, THAT, THE EFFICIENCY OF FRD IS ONLY A FEW PERCENT SMALLER THAN THAT OF OLD SOLUTIONS, AND THAT USE OF THE EQUILIBRIUM (SERVICEABILITY) METHODS AIMED TOWARD FULL REDISTRIBUTION (INPREFERENCE TO THE MORE COMPLEX OPTIMAL METHODS) IS A REALISTIC PROPOSAL FOR DESIGN PRACTICE AND INVOLVES ONLY A MINOR PENALTY IN STEEL CONSUMPTION. /RRL(A)/

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Filing Info

  • Accession Number: 00208711
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Apr 18 1971 12:00AM