STUDY OF LONG SPAN PRESTRESSED CONCRETE BRIDGE GIRDERS

NEW SAFETY STANDARDS ADOPTED BY THE AASHO COMMITTEE ON BRIDGES FOR INTERSTATE AND OTHER HIGH SPEED HIGHWAYS RECOMMEND THAT THE RIGHTHAND PIERS ON UNDERCROSSING BE ELIMINATED AND THAT 30-FOOT MINIMUM LATERAL CLEARANCES ON EITHER SIDE OF ALL TRAVEL LANES BE PROVIDED. COMPLIANCES ON EITHER SIDE OF ALL TRAVEL LANES BE PROVIDED. COMPILANCE WITH THIS CRITERIA ON A TWO-WAY, FOUR-LANE UNDERCROSSING REQUIRES A GIRDER SPAN OF 112 FT. FOR A RIGHT ANGLE CROSSING. THE SPAN INCREASES TO 160 FT. FOR A 45 DEG SKEW CROSSING. FOLLOWING THE SAME CRITERIA ON ONE-WAY, TWO LANE UNDERCROSSINGS THE REQUIRED GIRDER SPAN BECOMES 130 FT. FOR A RIGHT ANGLE CROSSING AND INCREASES TO 175 FT. FOR A 45 DEG SKEW CROSSING. THE LARGEST PRESTRESSED GIRDER PRESENTLY BEING BUILT IN THE COLORADO AREA IS A TYPE IV AASHO, WHICH WILL ECONOMICALLY SPAN ABOUT 105 FEET. THUS IT BECAME OBVIOUS THAT IF THE PRESTRESSED INDUSTRY IN THE COLORADO AREA INTENDED TO CONTINUE TO PARTICIPATE IN THE BRIDGE GIRDER BUSINESS, IT HAD TO DEVELOP A NEW STANDARD GIRDER SECTION OR SYSTEM OR PRECAST GIRDER SEGMENTS THAT WOULD ECONOMICALLY SPAN ABOUT 150 FEET. CREATION OF SUCH A SECTION ENTAILED DEVELOPMENT OF TWO COMPUTER PROGRAMS. ONE GENERATES UNIVERSAL GIRDER DESIGN CHARTS THAT ALLOW FINAL GIRDER DESIGNS FOR VARIABLE GIRDER SPACINGS AND SPANS TO BE READ DIRECTLY FROM GRAPHS. ANOTHER GENERATES COST DATA THAT ALLOWS FINAL BRIDGE COSTS TO BE COMPARED USING OPTIMUM GIRDER SPACING COST CURVES. NINE GIRDER SECTIONS ARE STUDIED IN DEPTH: TYPE IV, V, AND VI AASHO SECTIONS, THE WASHINGTON STATE 120 AND 100 SERIES SECTION, AN OREGON STATE SECTION, AND FOUR PROPOSED COLORADO STANDARD SECTIONS. DATA IS DEVELOPED FOR BOTH STONE AND LIGHTWEIGHT CONCRETE GIRDERS WITH CONCRETE STRENGTHS VARYING FROM 5000 TO 7000 PSI. DRAWING FROM THIS STUDY, THE COLORADO DIVISION OF HIGHWAYS HAS ADOPTED A NEW COLORADO STANDARD GIRDER SECTION, THE G-68. THIS IS AN INTERMEDIATE DEPTH GIRDER CAPABLE OF SPANNING ABOUT 130 FEET. /AUTHOR/

  • Authors:
    • Jacques, F J
  • Publication Date: 1970-11

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  • Accession Number: 00209805
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 2 1973 12:00AM