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August 2008DFI Case Histories Deep Foundations
Helical Pile Foundation for Alexan Broadway Parking
StructureHoward A. Perko, Ph.D., P.E.
Magnum Piering, Inc.
August 2008DFI Case Histories Deep Foundations
Outline
• Project Introduction• Foundation Design• Installation• Load Testing• Conclusions
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August 2008DFI Case Histories Deep Foundations
Project Introduction
• Brownfield Site in Denver, CO• 4-Story Parking Structure• Pre-cast Concrete Construction• 50 - 500 kip Column Loads• Shear Wall Loads = 50 kip/ft• 36,000 sf Footprint• Underground Storm Detention
August 2008DFI Case Histories Deep Foundations
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August 2008DFI Case Histories Deep Foundations
August 2008DFI Case Histories Deep Foundations
Subsurface Conditions
20 feet Trash Fill
10 feet Loose Sand
5 feet Expansive ClaystoneSandstone Bedrock
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August 2008DFI Case Histories Deep Foundations
Foundation Design
Magnum 6” Helical Piles
August 2008DFI Case Histories Deep Foundations
Lateral Pile Analysis
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August 2008DFI Case Histories Deep Foundations
Shear Wall Model
August 2008DFI Case Histories Deep Foundations
Shear Wall Results
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August 2008DFI Case Histories Deep Foundations
Foundation Plan
August 2008DFI Case Histories Deep Foundations
Green Alternative
• Efficient Design of Helical Pile Resulted in Reduced Carbon Footprint
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August 2008DFI Case Histories Deep Foundations
Installation
August 2008DFI Case Histories Deep Foundations
Installation
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August 2008DFI Case Histories Deep Foundations
Installation
• Monitor Torque Readings until Driving Criteria is Satisfied
• 42,000 ft-lbs
August 2008DFI Case Histories Deep Foundations
Compression Load Testing Helical pier compression test: Alexan Broadway Station
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Applied Load (Ibs)
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Ave Dial Readings
DL=100.00 kips
Figure 1
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August 2008DFI Case Histories Deep Foundations
Tension Load Testing Helical pier tension test: Alexan Broadway Station
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Applied Load (Ibs)
Dis
plac
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t (in
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Ave Dial ReadingsDL=50.00 kips
Figure 1
August 2008DFI Case Histories Deep Foundations
Conclusions
• Large Diameter Helical Piles Support Loads as High as 50-100 Tons
• Helical Piles are an Effective Foundation for Brownfield Sites
• Helical Piles are an Environmentally Friendly Foundation
• Quality Assurance through Calculations, Torque Monitoring, and Load Tests
