SEISMIC: Impact of Inspection Tube Placement on Structural Performance of CIDH Piles

The current Caltrans practice requires designers to show the location of inspection tubes in drilled shafts (wet pours) on the structural plans. A typical detail shown in Memo to Designers (MTD 3-1) for a Cast-In-Drilled-Hole (CIDH) pile requires the clear spacing between a tube and adjacent bars to be at least 3 inches, and the clear spacing between the bars adjacent to the tubes (on both sides) to be at least 8.5 inches. Per Caltrans Bridge Design Specifications, the maximum spacing for longitudinal bars in a column is 8" (center to center), which may be applicable to shafts as well. The purpose of this requirement is to provide enough support for cage stability and also to maintain the circular shape for confinement if plastic hinge is to form in the structural element. The above requirements are in conflict for pile shafts constructed under slurry displacement method.


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    • Status: Active
    • Funding: $435290
    • Sponsor Organizations:

      California Department of Transportation

      1227 O Street
      Sacramento, CA  United States  95843
    • Project Managers:

      Sikorsky, Charles

    • Performing Organizations:

      Regents of the University of California, San Diego

      San Diego, CA  United States 
    • Principal Investigators:

      Shing, P

    • Start Date: 20100122
    • Expected Completion Date: 20160430
    • Actual Completion Date: 0
    • Source Data: RiP Project 27730

    Subject/Index Terms

    Filing Info

    • Accession Number: 01466054
    • Record Type: Research project
    • Source Agency: California Department of Transportation
    • Files: RIP, STATEDOT
    • Created Date: Jan 3 2013 3:09PM