asce oc branch - geo-institute dinner presentation: fundamentals of torque down piles

FUNDAMENTALS OF TORQUE DOWN PILESOctober 24, 2017 Presentation to ASCE Orange County Geo‐Institute

• WHAT IS A TORQUE DOWN PILE?• General Description• History• Installation Procedures• Typical Capacities

• HOW DO TDPs WORK?• ADVANTAGES OF THE TDP• CASE HISTORIES

TORQUE DOWN PILES

• 12.75‐INCH‐DIAMETER STEEL PIPE (TYPICAL)

• CAN GO TO LARGER DIAMETER (NORTHRIDGE HOSPITAL)

• 3/8‐INCH WALL THICKNESS (TYPICAL)• CONCRETE‐FILLED STEEL PIPE PILE (CFSP) – CALTRANS DESIGNATION

WHAT IS A TORQUE DOWN PILE?


• 3/8‐INCH WALL THICKNESS• PATENTED TIP DESIGN



• 3/8‐INCH WALL THICKNESS• PATENTED TIP DESIGN• INSTALLED USING TORQUE AND CROWD


• DEVELOPED FOR A PROJECT IN SOUTHERN CALIFORNIA

• PROJECT REQUIREMENTS:• ALTERNATIVE TO DRIVEN PILES• LOW NOISE AND VIBRATION• NO SPOILS• EQUIVALENT CAPACITY• EQUIVALENT PRODUCTION RATES• COST

DEVELOPMENT OF THE TDP

HOW THE TDP IS INSTALLED

• PILE HOOKUP

INSTALLATION PROCEDURES

• PILE HOOKUP• LOFT PILE


• PILE HOOKUP• LOFT PILE• POSITION AND PLUMB PILE


• PILE HOOKUP• LOFT PILE• POSITION AND PLUMB PILE• INSTALL


• PILE HOOKUP• LOFT PILE• POSITION AND PLUMB PILE• INSTALL• WELDED SPLICE


• PILE HOOKUP• LOFT PILE• POSITION AND PLUMB PILE• INSTALL• WELDED SPLICE• INSTALL REBAR


• PILE HOOKUP• LOFT PILE• POSITION AND PLUMB PILE• INSTALL• WELDED SPLICE• INSTALL REBAR• FILL WITH CONCRETE


• DESIGN CAPACITY TYPICALLY CONFIRMED THROUGH STATIC LOAD TESTING

• TYPICAL ULTIMATE CAPACITIES:• DENSE SANDS: 400 – 800 KIPS• STIFF CLAYS: 200 – 400 KIPS• WEAK ROCK: TESTED TO 1000 KIPS

• CALCULATED LATERAL CAPACITY SIMILAR TO 14‐INCH‐SQUARE CONCRETE PILE

CAPACITY OF THE TDP

• FULL DISPLACMENT PILE• PILE IS SCREWED/TORQUED INTO PLACE

• GENERATES HIGH LATERAL STRESSES IN SURROUNDING SOIL

• IN GRANULAR SOIL, DENSIFIES SURROUNDING SOIL

• HIGH LATERAL STRESSES FROM DISPLACEMENT INCREASES ADHESION/SKIN FRICTION

HOW DOES THE TDP WORK?

• ABLE TO PENETRATE INTO DENSE GRANULAR SOIL LAYERS, WHICH INCREASES CAPACITY

• CAPACITY THROUGH SIDE FRICTION AND END BEARING

HOW DOES THE TDP WORK?

• LOW VIBRATION• LOW NOISE• FLEXIBILITY• OBSTRUCTIONS ARE MANAGEABLE – CAN UNSCREW PILE IF NEEDED

• LITTLE TO NO SPOILS• SAFETY• LARGE AMOUNT OF LOAD TEST DATA (100+ PROJECTS) AVAILABLE FOR DIFFERENT SOIL CONDITIONS

ADVANTAGES OF THE TDP

LOW NOISE AND VIBRATION

CAN CONFIRM SUBSURFACE DATA

FLEXIBILITY OF INSTALLATION

OBSTRUCTIONS ARE MANAGEABLE

LITTLE TO NO SPOILS

PREDRILLING

CASE HISTORIES

• Los Angeles International Airport, Modernization of Terminals 1 and 6

• Northridge Hospital Medical CenterService Elevator Tower

• Building 45 at Boeing Facility in Huntington Beach

• DESIGN‐BUILD OF NEW AIRPORT TENANT IMPROVEMENTS, INCLUDING PASSENGER BRIDGES

• MINIMAL IMPACT ON AIRPORT OPERATIONS

• ALTERNATIVE TO LARGE‐DIAMETER DRILLED SHAFTS

• DENSE TO VERY DENSE NATIVE SAND AT GROUND SURFACE

LAX TERMINAL 6

LAX TERMINAL 6

• CHALLENGE TO INSTALL PILES IN DENSE TO VERY DENSE SANDS TO ACHIEVE REQUIRED COMPRESSION AND TENSION CAPACITIES

• TEST PILE WAS INSTALLED IN CORED HOLES THROUGH EXISTING CONCRETE APRON

• REACTION PILES FOR LOAD TEST USED AS “INDICATOR PILES”

• R‐1 ATTEMPTED WITHOUT PREDRILLING – MET REFUSAL AT 16 FEET.

• R‐2 LOCATION PREDRILLED TO 25 FEET – HOLE CAVED TO 10 FEET

LAX TERMINAL 6

• R‐2 MET REFUSAL AT 19 FEET – VERY HIGH TORQUE BELOW A DEPTH OF 15 FEET

• PREDRILL DEPTH FOR R‐3 REDUCED TO 15 FEET –PILE INSTALLED TO DEPTH OF 17.7 FT

• TP‐1 PREDRILLED TO 15 FEET. HOLE CAVED TO 10 FEET. AFTER INITIAL REFUSAL AT 16 FEET, PILE INSTALLED TO DEPTH OF 17.9 FEET

• SOIL REMOVED TO DEPTH OF 5.4 FEET AROUND PILE, RESULTING IN TEST PILE LENGTH OF 12.5 FEET

LAX TERMINAL 6

LAX TERMINAL 6

LAX TERMINAL 6

• ULTIMATE COMPRESSION CAPAPACTY – 365 KIPS• ULTIMATE TENSION CAPACITY – 180 KIPS• USED COYLE & CASTELLO (1982) TO COMPUTE CAPACITIES• COMPUTED ULTIMATE END‐BEARING OF 225 KSF• COMPUTED ULTIMATE SKIN FRICTION OF 3.82 KSF USING

BACK‐CALCULATED K VALUE OF 5.0 AND FRICTION ANGLE BETWEEN PILE AND SAND OF 29 DEGREES

• RECOMMENDED LATERAL CAPACITIES OF 21 KIPS FOR FREE‐HEAD CONDITION AND 45 KIPS FOR FIXED‐HEAD @ 0.25 INCHES OF PILE‐HEAD DEFLECTION

• RECEIVED APPROVAL FROM CITY OF LOS ANGELES DEPARTMENT OF BUILDING & SAFETY

• TORQUE DOWN PILES AS ALTERNATIVE TO DRILLED SHAFTS• LADBS REQUIRED COMPRESSION, TENSION AND LATERAL LOAD TESTS AT 2

LOCATIONS – NORTH AND SOUTH CONCOURSES• 15 FEET OF UNDOCUMENTED FILL WAS TO BE IGNORED IN DETERMINING

VERTICAL AND LATERAL CAPACITIES

LAX TERMINAL 1

LAX TERMINAL 1

TEST PILE PROGRAM• TEST PILE 1:• INSTALLED WITHOUT PREDRILLING• REFUSAL MET AT DEPTH OF 33.7 FT

• TEST PILE 2:• INITIALLY INSTALLED WITHOUT

PREDRILLING – MET REFUSAL AT 25 FT• REINSTALLED TO DEPTH OF 31.6 FEET

AFTER PREDRILLING TO 30 FEET WITH 12‐INCH‐DIAMETER AUGER – AUGER REVERSED TO LEAVE CUTTINGS IN HOLE

LAX TERMINAL 1

LAX TERMINAL 1

• TEST PILE 1:• ULTIMATE COMPRESSION CAPACITY OF

580 KIPS (510 KIPS – DAVISSON)• ULTIMATE TENSION CAPACITY OF 400

KIPS (360 KIPS – DAVISSON)• LATERAL LOAD OF 58 KIPS FOR 0.5 INCH

OF PILE‐HEAD DEFLECTION

• TEST PILE 2:• COMPRESSION LOAD OF 700 KIPS

APPLIED WITHOUT REACHING FAILURE• TENSION LOAD OF 400 KIPS APPLIED

WITHOUT REACHING FAILURE• LATERAL LOAD OF 50 KIPS FOR 0.5 INCH

OF PILE‐HEAD DEFLECTION

COMPRESSION LOAD TEST SET‐UP

LAX TERMINAL 1

LAX TERMINAL 1

GAUGES SUPPORTED WITH FORK LIFT

• AFTER DISCOUNTING CONTRIBUTION FROM SKIN FRICTION IN FILL (ESTIMATED TO BE 130 KIPS) – RECOMMENDED ULTIMATE CAPACITIES OF 405 KIPS FOR COMPRESSION AND 195 KIPS FOR TENSION

• LATERAL CAPACITY OF 28 KIPS FOR FREE‐HEAD CONDITION AND 0.25 INCH OF PILE‐HEAD DEFLECTION

• NO REDUCTION FOR PREDRILLING ‐PRODUCTION PILES PREDRILLED TO 30 FEET

• BACK‐CALCULATED ULTIMATE END BEARING OF 238 KSF FOR TEST PILE 1 (WEAKER PILE)

• COMPUTED (ESTIMATED) SKIN FRICTION VALUES RANGING FROM 3 TO 4 KSF IN DENSE SAND AND 5 KSF IN VERY DENSE SAND

LAX TERMINAL 1

GAP REMAIING AFTER LATERAL LOAD TEST

NORTHRIDGE HOSPITAL –SERVICE ELEVATOR TOWER

• SERVICE ELEVATOR TOWER ADJACENT TO EXISTING HOSPITAL BUILDING

• BOTTOM OF SERVICE ELEVATOR CAP IS 18‐24 FEET BELOW GROUND SURFACE

• NO ACCESS FOR TEST PILE PROGRAM AT PROPOSED TOWER LOCATION

• OSHPD REVIEW• LARGER‐DIAMETER TORQUE

DOWN PILES REQUIRED TO MEET PILE DEFORMATION CRITERIA


TEST PILE PROGRAM• MODIFIED TORQUE DOWN PILES –

16‐INCH O.D. (.375‐INCH WALL THICKNESS) WITH TAPER AT END TO FIT NORMAL TIP

• TO DETERMINE THE IMPACT OF REMOVING 24 FEET OF SOIL, AMEC CALLED FOR TESTING TWO SETS OF PILES AT LENGTHS OF 24 AND 74 FEET (4 PILES TOTAL) IN BOTH COMPRESSION AND TENSION

• LATERAL LOAD TESTING OF BOTH 74‐FOOT‐LONG TEST PILES

• ACCEPTANCE CRITERIA FOR BOTH LOAD AND DEFLECTION


175 KIPS @ 0.15 INCHES


SOIL CONDITIONS• 0‐7 FT – CLAYEY SAND FILL (N = 17)• 7 – 17 FT – CLAYEY SAND/CLAYEY

GRAVEL (N = 8 – 17)• 17 – 30 FT – LEAN CLAY (N = 0 – 6) –

MOISTURE CONTENTS – 28‐35%• 30 – 61 FT – INTERBEDDED CLAY,

SANDY CLAY & CLAYEY SAND (N = 4 –20)

• 63 – 81 FT – CLAYEY SAND AND CLAY WITH SAND (N = 26 – 42)

• GROUNDWATER AT APPROX. 30 FT


REFUSAL MET AT 69 FEET FOR BOTH 74A AND 74B


24‐FOOT‐LONG PILE – TESTED IN COMPRESSION 12 DAYS AFTER INSTALLATION

69‐FOOT‐LONG PILE – TESTED IN COMPRESSION12 DAYS AFTER INSTALLATION


TEST PILE 74A – FIRST TENSION TEST PERFORMED 2 DAYS AFTER COMPRESSION TEST

TEST PILE 74A – SECOND TENSION TEST PERFORMED ON 12/10/11 ‐ 19 DAYS AFTER FIRST TENSION TEST

200 KIPS @ 0.3 INCH

200 KIPS @ 0.15 INCH


LATERAL LOAD TEST RESULTS –TEST PILE 74B

12.6 KIPS ‐ .044 INCH OF DEFLECTION


SUMMARY OF PILE LOAD TEST PROGRAM• COMPRESSION TESTS MET CAPACITY AND DEFORMATION REQUIREMENTS• TENSION TESTS MET CAPACITY BUT NOT DEFORMATION REQUIREMENTS FOR

INITIAL TENSION TESTS (PERFORMED 2 DAYS AFTER COMPRESSION TESTING OF SAME PILE)

• TENSION TESTS MET CAPACITY AND DEFORMATION REQUIREMENTS USING SECOND SET OF TENSION TESTS

• LATERAL CAPACITY GREATLY EXCEEDED ESTIMATED CAPACITY• AMEC CONSERVATIVELY USED INITIAL TENSION PILE LOAD TEST RESULTS AND

REANALYZED PILE GROUP BEHAVIOR


PRODUCTION PILE TEST RESULTS• PRODUCTION PILES INSTALLED

PRIOR TO EXCAVATION• COMPRESSION PILE INSTALLED ON

6/3/14 AND TESTED ON 8/16/14 –TESTED LENGTH OF 51.5 FEET

• COMPRESSION PILE LOADED TO 705 KIPS WITH 0.53 INCH OF DEFLECTION

• TENSION PILE INSTALLED ON 5/29/14 AND TESTED ON 8/16/14 –TESTED LENGTH OF 51.5 FEET

• TENSION PILE LOADED TO 492 KIPS WITH 0.45 INCH OF DEFLECTION

204 k ‐ .097 inch

313 k ‐ .134 inch

• RESEARCH FACILITY BUILT WITHIN EXISTING WAREHOUSE

• PROJECT COMPONENTS:• VERTICAL PILES• BATTERED PILES• SHORING• STATIC LOAD TEST

BOEING ‐ BUILDING 45

BOEING – BUILDING 45

BOEING – BUILDING 45

TESTED AFTER 2 DAYS OF SET‐UP

TESTED AFTER 26 DAYS OF SET‐UP

• NO VIBRATION, LOW NOISE, DRIVEN OR DRILLED PILE ALTERNATIVE

• TYPICAL ULTIMATE COMPRESSION CAPACITIES OF 300 TO 600 KIPS

• TYPICAL ULTIMATE TENSION CAPACITIES OF 200 TO 400 KIPS

• SIMPLE – INSTALLED USING CONVENTIONAL EQUIPMENT• FLEXIBLE – PILE LENGTHS ARE EASILY MODIFIED IN FIELD• SAFETY• LARGE AMOUNT OF LOAD TEST DATA AVAILABLE

SUMMARY

THANK YOU/QUESTIONS?

asce oc branch - geo-institute dinner presentation: fundamentals of torque down piles

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