CONSTRUCTION PRACTICES FOR PLACING 48-INCH PRECAST, PRESTRESSED CONCRETE PILING IN DEEP WATER

THE PROPOSAL TO CONSTRUCT A STRUCTURE ACROSS MORE THAN A MILE OF OPEN WATER UP-TO 80 FT DEEP WAS THE BEGINNING OF AN EXTENSIVE ENGINEERING ECONOMIC ANALYSIS TO DETERMINE THE TYPE AND LENGTH OF STRUCTURE TO FIT THE SITE. A COMPOSITE I-BEAM STRUCTURE 5655.5 FT. LONG SUPPORTED ON A DRIVEN PILE BENT WAS CHOSEN. THE PILE BENTS CONSISTED OF EITHER 8 OR 12 PILES, WITH EACH PILE 48 IN. IN DIAMETER. EACH OF THE 276 PILES WOULD BE A PRESTRESSED, PRECAST CONCRETE CYLINDER PILES. SOIL BORINGS INDICATED THE LENGTH WOULD VARY FROM 25 TO 176 FT. TO WITHSTAND HANDLING AND DRIVING, THE WALL THICKNESS WOULD BE 5 IN. WITH SPIRAL REINFORCING, STRESSING TENDONS AND 8 NO. 4 BARS. EACH OF THE SIXTEEN 7/16-IN. DIAMETER PRESTRESSING CABLES WAS TENSIONED TO STRESS THE 7000-PSI CONCRETE TO 1100 PSI. DRIVING SPECIFICATIONS REQUIRED THE PILING TO BE SEATED WITH 50 BLOWS PER INCH BY A 60,000 FT-LB HAMMER IN NIOBRARA CHALK. THE CONTRACTOR ELECTED TO CAST THE PILING AT THE SITE. THE FIRST METHOD OF PILE PLACEMENT USED A THREE-FINGER JET TO PLACE THE PILING NEAR CHALK AND A HAMMER TO DRIVE THE PILE INTO CHALK. THIS METHOD PROVED INEFFECTIVE, AND SUBSEQUENTLY A SINGLE JET WAS ATTACHED TO THE PILE AND THE PILE JETTED AND DRIVEN SIMULTANEOUSLY WITH THE FINAL SEATING FOR BEARINGS AFTER REMOVAL OF THE JETS. AFTER EACH BENT WAS DRIVEN THE PILES WERE BACKFILLED WITH SAND, CLASS C AND CLASS A CONCRETE. SOME OF THE PILES WERE DRIVEN A TOTAL OF 7000 BLOWS. AFTER THE BENTS WERE COMPLETED, CRACKS WERE OBSERVED IN THE PILING IN JANUARY 1964. INSPECTION REVEALED 52 PILES THAT WOULD REQUIRE REPAIR. THE DAMAGED PILES WERE OPENED UP, CLEANED AND BACK-FILLED WITH DRY-PACK CONCRETE, AND A STEEL REINFORCING SHELL WAS EPOXIED AND BOLTED INTO PLACE. SUCCESSFUL USE OF THESE PILES REQUIRE A KNOWLEDGE OF THE LENGTH TO CAST EACH PILE AND AN ACCURATE BEARING ESTIMATION. DURING CONSTRUCTION, PROPER SUPERVISION MUST BE EXERCISED TO INSURE A SOUND PILE. /AUTHOR/

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• Supplemental Notes:
  • No 287, pp 1-11, 13 FIG
• Authors:
  • Grimes, W W
• Publication Date: 1969

Media Info

• Serial:
  • Highway Research Record
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Backfilling; Bents; Bolts; Chalks; Construction management; Economic analysis; Epoxides; Hydraulic jetting; I beams; Location; Material reinforcement; Pile driving; Pile groups; Precast concrete; Prestressed concrete; Reinforcing steel; Sand; Spirals; Support piles
• Uncontrolled Terms: Cylinders; Jetting
• Old TRIS Terms: Epoxy; Placement; Prestressed concrete piles
• Subject Areas: Construction; Economics; Highways; Maintenance and Preservation;

Filing Info

• Accession Number: 00215212
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Dec 22 1994 12:00AM