LIMIT DESIGN OF CONTINOUS CONCRETE BRIDGE GIRDERS

A LIMIT DESIGN METHOD FOR CONTINOUS REINFORCED CONCRETE GIRDERS IS PRESENTED, WHICH RESULTS IN STRUCTURES SATISFYING COLLAPSE AND SERVICE CONDITIONS. THE GIRDER IS DESIGNED SUCH THAT IT WILL RESIST ANY LOADING CONDITION BEFORE THE ULTIMATE LOAD LEVEL IS REACHED. ELASTIC BEHAVIOR IS ASSURED AT WORKING LOADS AS WELL AS ACCEPTABLE MAXIMUM STRESSES, CRACKS AND DEFLECTIONS. THE DESIGN PROBLEM REDUCES TO DERIVING A SET OF REDUCTION FACTORS (OR YIELD SAFETY PARAMETERS) OF THE ELASTIC MOMENT ENVELOPE. THESE UNKNOWNS ARE DETERMINED FROM LIMIT EQUILIBRIM EQUATIONS ASSOCIATED WITH POSSIBLE MODES OF COLLAPSE OF THE GIRDER. A SIMPLE TECHNIQUE FOR DETERMINING THE UNKNOWN YIELD SAFETY PARAMETERS AND A GRAPHICAL PROCEDURE FOR PRACTICAL DESIGN ARE PRESENTED. TWO SUGGESTED DEFINITIONS FOR THE ULTIMATE LOAD ARE INVESTIGATED AND RELATIVE STEEL CONSUMPTION FOR WORKING STRESS, ULTIMATE STRESS AND LIMIT DESIGN METHODS ARE COMPARED. IT IS CONCLUDED THAT THE PRESENTED LIMIT DESIGN APPROACH, BESIDES BEING SAFE AND SERVICEABLE, CAN PRODUCE WORTHWHILE STEEL SAVINGS WHEN APPROPRIATE LOAD FACTORS ARE USED. /RRL/A/

• Supplemental Notes:
  • No 23, pp 423-426, 8 FIG, 2 TAB, 12 REF
• Corporate Authors:

  Intl Symp Concr Bridge Des Proc /Can

  ,    
• Authors:
  • Gerstle, K N
  • Cohn, M Z
• Publication Date: 1969

Subject/Index Terms

• TRT Terms: Beams; Breaking loads; Collapse; Continuous structures; Cracking; Deflection; Elasticity (Mechanics); Equations; Girders; Load factor; Reinforced concrete bridges; Steel; Stresses; Ultimate load design
• Uncontrolled Terms: Continuous beams
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00208694
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: Nov 18 1970 12:00AM