Mitigation of Anomalies In CIDH Piles

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Mitigation of Anomalies In CIDH Piles

• Anomaly Identification
• Design Concerns
• Remediation Methods
• Standard Mitigation Plan

One test is worth a thousand expert opinions...
Presented By Brian Liebich, P.E.
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Mitigation Process

• Anomaly Identification
• Design Review
• Contractor Plan
• Review / Approval
• Perform Repair
• Evaluation

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Mitigation of Anomalies in CIDH Piles

• Anomaly Identification

One test is worth a thousand expert opinions...
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Need for Non-Destructive Evaluation

• Visual Observation Difficult / Inadequate
• Structural Element Constructed Under Field
  Conditions
• Critical Design Requirements

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Non-Destructive Testing

• Gamma-Gamma Logging Primary Method
• Performance Evaluation for Homogeneity
• Test Every Wet CIDH Pile

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Sizing the Anomaly

• Representative Sample / Proportional
  Apportionment
• Can Use CSL to Further Define Anomaly

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Mitigation of Anomalies in CIDH Piles

• Design Concerns

One test is worth a thousand expert opinions...
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Designer Involvement

• Foundation Testing Knows Anomaly Location
• Designers Know Importance of an Anomaly
• Three Design Inputs Structural, Geotechnical,
  Corrosion

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Structural

• Usually Most Critical
• Lateral / Shear Cannot be Transferred
• Zone of Maximum Moment

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Geotechnical

• Significant Portion of Skin Friction Reduced
• End Bearing Compromised
• Axial Capacity Diminished

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Corrosion

• Corrosive Environment
• Water Table Influence / Oxygen
• Stray Current

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Identify Critical Defects Quickly
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Mitigation of Anomalies in CIDH Piles

• Remediation Methods

One test is worth a thousand expert opinions...
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Successful Repair

• No One Size Fits All
• Meets Design Requirements
• Assurance of Repair
• Timely Resolution

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How Mitigation Methods are Selected

• Contractor Selects
• Mitigation Committee Approves
• Competing Concerns Cost vs. Effectiveness

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Mitigation Methodologies

• Replacement / Supplement
• Structural Bridging
• Unearth and Recast
• Pressure Grouting

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Replace / Supplement

• Based on Design Concerns
• May not be Possible
• Typically Most Expensive

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Structural Bridging

• Core Drill Hole
• Insert Steel Supplement
• Grout into Place

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Unearth and Recast

• Physical Replacement
• Visual Inspection
• Access and Restoration

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Pressure Grouting

• Gain Access Usually PVC
• Wash and Clean Deleterious Material
• Inject Grout

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Field Inspection

• Contractor Follows Plan
• Washing Operations
• Water Test Results
• Grout Injection Volumes and Pressures

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Downhole Camera

• QA of Contractor Procedure
• Verify Anomaly Type / Extent
• Useful for Confirming Anomaly

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Mitigation of Anomalies in CIDH Piles

• Standard Mitigation Plan

One test is worth a thousand expert opinions...
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ADSC Standard Mitigation Plan

• No One Size Fits All But not Reinvent the
  Wheel
• Cooperatively Developed ADSC - Caltrans
• Accelerated Review of Repair Plans
• Basic Repair (A) or Grouting (B)

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Basic Repairs

• Expose / Unearth
• Chip Visible Anomaly
• Recast
• Restore Soil

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Pressure Grouting

• High-Pressure Water Jetting, Clean/Scour
• Water Test for Grout Selection
• Grouting Process Detailed
• Flowchart

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Mitigation of Anomalies In CIDH Piles

• Anomaly Identification
• Design Concerns
• Remediation Methods
• Standard Mitigation Plan

One test is worth a thousand expert opinions...