LARGE DIAMETER DRILLED SHAFTSMarie Masters Fisk, P.E.

Table of contents

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What is considered Large Diameter?

Use of Large Diameter under 2014 Spec

Why use?

Design & Construction Considerations

Control Measures

Example

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What is considered Large Diameter?

5’ dia or greater

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2014 Spec book use

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60" dia 66" dia 72" dia 78" dia 84" dia 92" dia 96" dia 108" dia 120" dia 132" dia 144" dia

32 7 14 3 12 2 8 3 7 1 2

2014 Spec book - # of time Bid Code has been used

Reasons to use Large Diameter DS?

Space

High Loads

Faster?

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Design Considerations

FD standard only goes up to 48” dia

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Construction Considerations

Cage

Install

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Control Measures

Thermal Integrity Profiler (TIP) testing – SS 4021

Item 405 – “Foundation Load Test.”

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Example TIP Results

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Example TIP Results

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When to use TIP testing?

Large diameter shafts

Mono-shafts

Shafts installed in water bearing sands (tricky

install)

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Load Test

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Statnamic Testing

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When to use Load Test?

When suspect deficient

When want to determine capacity

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Questions?

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