POST-TENSIONING PLUS SPECIAL VIBRATION SYSTEM AIDS PRODUCTION OF GIANT PRECAST PRESTRESSED GIRDERS

THE REPORT DESCRIBES THE PRODUCTION OF GIANT PRECAST, PRESTRESSED CONCRETE, BRIDGE GIRDERS. THE HEAVILY REINFORCED SECTIONS HAD TO BE CAST ON A RELATIVELY TIGHT TIME SCHEDULE. TO CONSOLIDATE THE CONCRETE, SPECIAL EXTERNAL VIBRATORS WERE DEVELOPED WHICH WERE PERMANENTLY MOUNTED TO THE FORMS. THE VIBRATORS ARE ATTACHED TO THE CHANNELS WELDED TO BOTH SIDES OF THE FORMS BETWEEN THE GUSSETS ON ALTERNATING 60- OR 80-IN. CENTERS MOUNTED HIGH AND LOW. A SPECIAL BRACKET USED TO MOUNT THE VIBRATORS AFFORDED FAST REMOVAL FOR EASY TRANSFER FROM FORM TO FORM. DETAILS ARE GIVEN OF THE HUGE ANCHOR-CANTILEVER GIRDERS AND ILLUSTRATIVE FIGURES ARE PRESENTED. THE CASTING METHOD FOR THESE MEMBERS WAS TO PLACE THE CONCRETE IN FIVE OR SIX LIFTS, FILLING FROM THE CENTER TO THE ENDS OF THE FORM. EACH BEAM REQUIRED APPROXIMATELY 30 CU YDS OF CONCRETE AND SIX VIBRATORS WERE OPERATED SIMULTANEOUSLY TO CONSOLIDATE THE MIX. ONE INTERNAL VIBRATOR WAS REQUIRED TO SATISFY STATE SPECIFICATION. A FEATURE OF THE CONSTRUCTION WAS THE FIELD SPLICE BETWEEN THE 90 FT, 47-TON ANCHOR GIRDER AND THE 82-FT 6-IN., 58-TON ANCHOR-CANTILEVER GIRDER. THESE SECTIONS WERE POST-TENSIONED ON A BARGE BEFORE ERECTION. EXTERNAL VIBRATORS MOUNTED ON THE STEEL FORM WERE USED TO CONSOLIDATE THE CONNECTING DIAPHAGM CONCRETE. THE 120-FT DROP-IN GIRDERS WERE PLACED BETWEEN THE DAPPED ENDS OF THE TWO ERECTED CANTILEVERS AND THEIR CONNECTING DIAPHRAGM WAS MADE.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/08879672
• Publication Date: 1973-7

Media Info

• Features: Figures;
• Pagination: p. 33-6
• Serial:
  • PRECAST/PRESTRESSED CONCRETE INSTITUTE. JOURNAL
  • Volume: 18
  • Issue Number: 4
  • Publisher: Precast/Prestressed Concrete Institute
  • ISSN: 0887-9672

Subject/Index Terms

• TRT Terms: Bridge design; Bridges; Cantilevers; Concrete; Consolidations; Diaphragms (Engineering); Girders; Posttensioning; Precast concrete; Structural design; Vibration devices; Vibratory equipment
• Uncontrolled Terms: Anchors
• Old TRIS Terms: Concrete vibrators; Diaphragms; Vibrators
• Subject Areas: Bridges and other structures; Construction; Highways;

Filing Info

• Accession Number: 00215676
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 19 1974 12:00AM