THE ULTIMATE LOAD CAPACITY OF BEAM AND SLAB BRIDGES

A LIMIT DESIGN PROCEDURE IS PRESENTED FOR THE DETERMINATION OF THE ABNORMAL LOAD CAPACITY OF A BEAM-AND- SLAB BRIDGE SYSTEM. IN MAKING SUCH CALCULATIONS, IT IS ASSUMED THAT ULTIMATE MOMENT CAPACITIES IN BENDING AND TORSION MAY BE CALCULATED INDEPENDENTLY AND INTERACTION MAY BE NEGLECTED. THE CONTRIBUTION TO ULTIMATE LOAD CAPACITY MADE BY DIAPHRAGMS IS SMALL AND MAY BE NEGLECTED. IF IT IS INCLUDED, A REASONABLE ESTIMATE OF THE TORSIONAL CAPACITY OF A SECTION MAY BE OBTAINED FROM THE SAND HEAP ANALOGY NEGLECTING THE CONTRIBUTION OF REINFORCEMENT. THE CONTRIBUTION TO ULTIMATE LOAD CAPACITY MADE BY THE SLAB IS SIGNIFICANT. A TWO-BEAM BRIDGE WITHOUT ANY INTERIOR DIAPHRAGMS WAS CONSIDERED. THESE DIAPHRAGMS MAKE NO SIGNIFICANT CONTRIBUTION TO LOAD CAPACITY FOR SINGLE-LANE LOADING AND INCREASE THE POSSIBILITY OF SHEAR-TORSION FAILURES.THE AMOUNT OF WEB REINFORCEMENT IN THE LONGITUDINAL BEAMS OF TWO- AND FOUR- BEAM REINFORCED CONCRETE BRIDGES REQUIRED BY AASHO AND CSA-S6 CODE PROVISIONS SEEMS TO BE INSUFFICIENT TO CARRY THE ADDED TORSIONAL SHEAR STRESS CAUSED BY ABNORMAL LOADS. THE AMOUNT OF ADDITIONAL TORSIONAL REINFORCEMENT REQUIRED CAN BE CALCULATED USING THE SUGGESTED MECHANISMS OF FAILURE. WHEN HIGH STRENGTH REINFORCEMENT IS USED, THE FULL STRENGTH MAY BE USED IN CALCULATING FLEXURAL CAPACITIES OF INDIVIDUAL MEMBERS.

• Supplemental Notes:
  • Rr 159, 23 PP, 21 FIG, 8 TAB, 8 REF, 1 APP
• Corporate Authors:

  Ontario Dept Hwys Jt Hwy Res Prog /Can

  ,    
• Authors:
  • Lash, S D
  • Nagaraja, R
• Publication Date: 1970-5

Subject/Index Terms

• TRT Terms: Beams; Bending; Breaking loads; Bridge construction; Bridge foundations; Bridges; Concrete; Construction; Diaphragms (Engineering); Material reinforcement; Reinforced concrete; Shear stress; Slabs; Torsion; Ultimate load design; Webbing
• Uncontrolled Terms: Concrete beams
• Old TRIS Terms: Diaphragms
• Subject Areas: Bridges and other structures; Construction; Highways;

Filing Info

• Accession Number: 00209241
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 17 1970 12:00AM