1. AASHTO Subcommittee on Construction Virginia Beach, Virginia August 2, 2011 Barry D. Siel, P.E. Senior Geotechnical Engineer FHWA-RC AASHTO Subcommittee on Construction Virginia Beach, Virginia August 2, 2011 Barry D. Siel, P.E. Senior Geotechnical Engineer FHWA-RC Fabrication and Placement of Drilled Shaft Reinforcing Cages

2. Attributes of Rebar Cages to Assure Good Constructability

3. Longitudinal Reinforcing

4. Selecting Bar Sizes: A Practical Compromise Make Bars as Large As Possible for Better Flow Paths for Concrete (Constructability)Make Bars as Large As Possible for Better Flow Paths for Concrete (Constructability) Make Bars as Small As Possible to Minimize Crack Size (Durability)Make Bars as Small As Possible to Minimize Crack Size (Durability) SplicesSplices Use Only Lap or Mechanical Splices Locate Splices As Deep As Possible

5. Splice 50 ft Below Top of Shaft

6. Transverse Reinforcing

8. Cage Design for Constructability Clear Spacing Between All Bars 5 D of Largest Clear Spacing Between All Bars 5 D of Largest Coarse Aggregate or 5 inches, (whichever is Coarse Aggregate or 5 inches, (whichever is larger) to Allow Placement of Concrete larger) to Allow Placement of Concrete Bundle Bars if Necessary Tie Transverse Steel Every Lap Tie Transverse Steel Every Lap

10. Concentric Rebar Cages

11. External Centralizer

14. Concrete Cover and Location Tolerance

16. Partial-Length Rebar Cage

17. No Out-Hooks if Casing Method is Possible Make Cages Full Depth if Casing Method is Possible Make Cages Full Depth if Casing Method is Possible Do Not Allow Welding Unless Weldable Steel is Specified Do Not Allow Welding Unless Weldable Steel is Specified Essentials of Cage Design for Constructability

18. Support Cage Above Bottom

19. Internal Bracing

21. Cage with Internal Bracing

22. Lifting Cages

28. Practical Tips on Storing and Handling Rebar Cages StorageStorage Keep it clean Cage Pick Up:Cage Pick Up: No permanent distortion Use of temporary stiffeners Use of Centralizers: External & InternalUse of Centralizers: External & Internal NDT Access Tubes: Straight & ParallelNDT Access Tubes: Straight & Parallel

29. QUESTIONS? AASHTO Subcommittee on Construction Virginia Beach, Virginia August 2, 2011 Barry D. Siel, P.E. Senior Geotechnical Engineer FHWA-RC AASHTO Subcommittee on Construction Virginia Beach, Virginia August 2, 2011 Barry D. Siel, P.E. Senior Geotechnical Engineer FHWA-RC