Richards Micro Pile Construction Methods and Materials
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Transcript of Richards Micro Pile Construction Methods and Materials
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Micropile ConstructionMethods & Materials
Presented BPresented ByTom Richards, Chief Engineer
Nicholson Construction CompanyNicholson Construction Company12 McClane Street, Cuddy, PA 1503112 McClane Street, Cuddy, PA 15031
Phone: 412.221.4500Phone: [email protected]@nicholsonconstruction.comt c a ds@ c o so co st uct o cot c a ds@ c o so co st uct o co
Including information fromDonald Bruce
GeoSystems, LP
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Soil Drilling Methods(excluding “Open Hole”)
• Single Tube Advancement (External flush)Single Tube Advancement (External flush)• Rotary Duplex• Rotary Percussive Duplex (Concentric)• Rotary Percussive Duplex (Eccentric)• Double Head Duplex• Auger• Auger• Sonic• “Self Drilling”
Slide Courtesy: GeoSystems LP
•Opening larger than casing size
External Flush Drilling
size•Risk of ground loss in cohesionless soils•Good cleaning of borehole•Tremie grouted through casing g g g- then pulled with tremie head or excess pressure - enhances lateral confinement
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Duplex Drilling
•Often specified- less risk•Minimal loss of ground in cohesionless soils•Grouted through the
i h ll dcasing - then pulled with tremie head or excess pressure
Duplex Drill Casing and Roller Bit
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Water Flush thru Duplex Ejector
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Rotary Eccentric Percussive Duplex DrillingWe call it Tubex
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Tubex Setup
Syst
ems,
rtesy
of C
on-T
ech
SB
C
“Self Drilling” Hollow Bars
Phot
o C
our
Vanc
ouve
r,
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Photo Courtesy of Con-Tech Systems, Vancouver, BC
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Rock Drilling Methods
• High Rotational Speed / Low Torque RotaryHigh Rotational Speed / Low Torque Rotary(e.g., coring)
• Low Rotational Speed / High Torque Rotary(e.g., tricone)
• Rotary Percussive• Top HammerTop Hammer• Down-the-hole Hammer
Slide Courtesy: GeoSystems LP
Micropiles – Classification Based on Grouting Method
Type A: Gravity
Type B: Pressureti th h igrouting through casing
Type C: Single, globalpost grout
Type D: Multiple,repeatable post grout
Slide Courtesy: GeoSystems LP & FHWA
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Type B Micropile(Same effect could be achieved through the drill head)
Slide Courtesy: GeoSystems LP
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Materials
St l C i• Steel Casing• Use Mill Secondary Oil Field
Casing• Typically Flush threaded joints• Typically Flush threaded joints • 80 ksi minYield Strength
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Typical Casing Joint
Casing End with Special Shear Rings
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Grooved Oversized Hole in Existing Foundation
Grooving Problems – AnkerBonder Manufacturer out of business
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Grooving Problem SolutionNichBonderdesigned by Tom Fleet with Danny Mirtand built by Tom Fleet, Star Iron, and
Tom JohnsonTom Johnson
Materials
• Grout• Neat Cement with
Water/Cement Ratio of 0.45• Compressive Strength of 4 6 ksi• Compressive Strength of 4-6 ksi
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Materials
• Reinforcing BarsReinforcing Bars• Grade 60• Grade 75• Grade 150• Centralizers are used
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Dywidag THREADBAR
• ASTM 615 & ASTM 722• Sizes #6 through #20 Grade 60 & 75• 5/8”, 7/8”, 1”, 1-1/4, 1-3/8”, 1-3/4”, 2-1/2” GR 150 / 160
Rebar with Centralizer Installation
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Syst
ems,
rtesy
of C
on-T
ech
SB
C
Ischebeck / Titan Bar Options MAI Similar
Phot
o C
our
Vanc
ouve
r,
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Quality Control
MATERIALSMATERIALS
Coupon Tests on Casing
Mill Certs on Bars
Grout Cubes - quality batching and mixing
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Equipment
DK 50
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Inside work completed at night
Photo Courtesy: GeoSystems LP
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Photo Courtesy: GeoSystems LP
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C 12
C14 - The only ones in North America!
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Photo Courtesy: GeoSystems LP
Basic Grouting Equipment
• Mixer• Mixer• Agitated hopper• Grout pump• Flow and pressure monitoring system• QC testing facility
Slide Courtesy: GeoSystems LP
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Grout Mixing Equipment
High-speed colloidal mixers are superior to standard slow-speed mechanical mixers
fbecause they produce grout of greater uniformity and with better hydration characteristics.
Slide Courtesy: GeoSystems LP
Grout Pumps
• Various types are available and should be• Various types are available and should be selected based on individual job requirements.
• Either piston pumps or progressive cavity pumps can be used.
• Mainly progressive cavity pumps are used• Mainly progressive cavity pumps are used.
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Photo Courtesy: GeoSystems LP
Photo Courtesy: GeoSystems LP
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REGROUT PUMPS
a.k.a Henderson Pumps
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Grout QC testing
Flow and pressure monitoring system