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AASHTO Subcommittee on ConstructionVirginia Beach, Virginia
August 2, 2011
Barry D. Siel, P.E.Senior Geotechnical Engineer
FHWA-RC
AASHTO Subcommittee on ConstructionVirginia Beach, Virginia
August 2, 2011
Barry D. Siel, P.E.Senior Geotechnical Engineer
FHWA-RC
Fabrication and Placement of Drilled Shaft Reinforcing CagesFabrication and Placement of Drilled Shaft Reinforcing Cages
Attributes of Rebar Attributes of Rebar Cages to Assure Good Cages to Assure Good ConstructabilityConstructability
Attributes of Rebar Attributes of Rebar Cages to Assure Good Cages to Assure Good ConstructabilityConstructability
Longitudinal ReinforcingLongitudinal Reinforcing
Selecting Bar Sizes: A Practical Selecting Bar Sizes: A Practical CompromiseCompromise
• Make Bars as Large As Possible for Better Flow Make Bars as Large As Possible for Better Flow Paths for Concrete (Constructability)Paths for Concrete (Constructability)
• Make Bars as Small As Possible to Minimize Make Bars as Small As Possible to Minimize Crack Size (Durability)Crack Size (Durability)
• SplicesSplicesUse Only Lap or Mechanical SplicesUse Only Lap or Mechanical SplicesLocate Splices As Deep As PossibleLocate Splices As Deep As Possible
Splice 50 ft Below Splice 50 ft Below Top of ShaftTop of Shaft
Transverse ReinforcingTransverse Reinforcing
Transverse ReinforcingTransverse Reinforcing
Cage Design for Constructability Cage Design for Constructability
• Clear Spacing Between All Bars Clear Spacing Between All Bars 5 D of Largest 5 D of Largest Coarse Aggregate or 5 inches, (whichever is Coarse Aggregate or 5 inches, (whichever is larger) to Allow Placement of Concretelarger) to Allow Placement of Concrete
Bundle Bars if NecessaryBundle Bars if Necessary
• Tie Transverse Steel Every LapTie Transverse Steel Every Lap
Concentric Rebar CagesConcentric Rebar Cages
External CentralizerExternal Centralizer
External CentralizerExternal Centralizer
External CentralizerExternal Centralizer
Concrete Cover and Location ToleranceConcrete Cover and Location Tolerance
Partial-LengthPartial-LengthRebar CageRebar Cage
• No Out-Hooks if Casing Method is PossibleNo Out-Hooks if Casing Method is Possible
• Make Cages Full Depth if Casing Method is Make Cages Full Depth if Casing Method is PossiblePossible
• Do Not Allow Welding Unless Weldable Steel is Do Not Allow Welding Unless Weldable Steel is SpecifiedSpecified
Essentials of Cage Design for Essentials of Cage Design for Constructability Constructability
Support Cage Above BottomSupport Cage Above Bottom
Internal BracingInternal Bracing
Internal BracingInternal Bracing
Cage with Internal BracingCage with Internal Bracing
Lifting CagesLifting Cages
Lifting CagesLifting Cages
Lifting CagesLifting Cages
Lifting CagesLifting Cages
Lifting CagesLifting Cages
Lifting CagesLifting Cages
Practical Tips on Storing and Handling Practical Tips on Storing and Handling Rebar Cages Rebar Cages
• Storage Storage Keep it cleanKeep it clean
• Cage Pick Up: Cage Pick Up: No permanent distortionNo permanent distortionUse of temporary stiffenersUse of temporary stiffeners
• Use of Centralizers: External & InternalUse of Centralizers: External & Internal
• NDT Access Tubes: Straight & ParallelNDT Access Tubes: Straight & Parallel
QUESTIONS?QUESTIONS?
AASHTO Subcommittee on ConstructionVirginia Beach, Virginia
August 2, 2011
Barry D. Siel, P.E.Senior Geotechnical Engineer
FHWA-RC
AASHTO Subcommittee on ConstructionVirginia Beach, Virginia
August 2, 2011
Barry D. Siel, P.E.Senior Geotechnical Engineer
FHWA-RC