AASHTO Subcommittee on Construction Virginia Beach, Virginia August 2, 2011 Barry D. Siel, P.E....

AASHTO Subcommittee on ConstructionVirginia Beach, Virginia

August 2, 2011

Barry D. Siel, P.E.Senior Geotechnical Engineer

FHWA-RC


August 2, 2011


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

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

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

Cage with Internal BracingCage with Internal Bracing

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?


August 2, 2011


FHWA-RC


August 2, 2011


FHWA-RC

AASHTO Subcommittee on Construction Virginia Beach, Virginia August 2, 2011 Barry D. Siel, P.E....

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