Automated Recording System for Jack In Pile-Final Recording S… · · 2015-11-19. Learning &Application of Multi‐Engineering Disciplines • Geotechnical & Structural Engineering

Automated Recording System for Jack In PileIr. Liew Shaw Shong

Geotechnical Automation & Innovation• Back Ground & Objectives

• Problem Statement

• Solutions & Future R&D

• Learning &Application of Multi‐Engineering Disciplines

• Case History

• Concluding Remarks

July 22, 2012 2‐Day Seminar on Advancement in Ground Investigation and Geotechnical Instrumentation2

Pile Foundation SupportLoad Carrying Capacity & Safety Factor

Are these Loadings a Static or Dynamic Actions?

Settlement Performance & Stiffness Response


Static InjectionNewton’s 3rd Law : Action = Reaction

Proof Loaded by Kentledge Static Loading

Until Injection Refusal (Short term)


Jack In Piling SystemDead Weight Ballast

Self Service Crane

Power Pack

Hydraulic Gripping System

Hydraulic Injection System

Movable Bearing Sleepers


Jack In Piling SystemHydraulic Actuators (2 & 4 Concentric Pairs)

Hydraulic Gripping System

‐ Curvature of Gripping arch to fit pile diameter

‐ Contact area for gripping friction


Schematic


Problem StatementInjection Obstruction (Boulders, shallow & intermittent hard layers) ‐ Preboring

Buckling in Prebored Hole & Toe Relaxation –Backfilling/Grouting

Kick‐out (Pile flexural distress) – Pointed Pile Shoe

Pile Heave (Soil displacement) & Toe Relaxation ‐Rejacking

Creeping Settlement – Longer Holding Time

Erroneous Recording







Erroneous Recording







Erroneous Recording







Erroneous Recording


Kick‐Out of Pile Toe






Erroneous Recording


Load (kN)

Settlement (mm)

Pile Heave






Erroneous Recording


Creeping Behaviour :

• Dissipation of excess pore pressure (Cohesive fine materials)

• High component of pile capacity on End Bearing on Stiff Fine Soils

• Imposed load near to Ultimate Resistance (Plastic deformation in Progressive Load Transfer of LoadPile)


Buckling in Prebored Hole & Toe Relaation –Backfilling/Grouting



Creeping Settlement

Erroneous Recording ‐Automation


Pile Joint Welding

Carbon Footprint : Energy to install a Pile, E = F(x)dx

SolutionsReal‐time Monitoring System

Wire spring LVDT Penetration Decoder

Pressure transducers for Jacking Load Measurement & Flag of Pile Grip

LCD Panel


Advantages

• Continuous monitoring and recording of Jacking Load & Pile Penetration (Good record of jacking resistance rather than erroneous manual recording, pile jointing, etc )

• Criterion to either timely manually cease or automated Jacking on Sudden Reduction of Jacking Load

• Reduce the workload of jacking rig operator

• Prevent uncontrolled structural damage to pile resulting in the abandonment of original damaged jacked pile and more compensation piles and pilecap enlargement are needed

• Rejacking of under capacity pile to maximise usable capacity of piles at risky areas where pile damage is expected if jacking is not controlled


Pile ProductivityCooling Duration for Pile Joint Welding

Application of Anti‐Corrosion Paint

Investigation using Thermal Imaging Tool

Natural Cooling & Induced Air Flow Cooling

Flux Cored Arch Welding (FCAW) / Gas Metal Arch Welding (GMAW)


Flux Cored Arch Welding (FCAW) / Gas Metal Arch Welding (GMAW)


1)PILE INSTALLATION PROCEDUREChecklist:‐1) Rock head level (______m)2) 400mm ø spun pile Class B (Working Load =120 Tonne, Grade 80)3) Jacking Load =2 x WL = 2 x 120= 240 Tonne

START INSTALL THE PILE

PLOT GRAPH OF JACKING LOAD VS DEPTH

CHECK THE CHANGE IN LOAD‐DEPTH GRADIENT‐JACKING MUST BE STOPPEDAT 100%, 150% AND 200% WLAND AT 1M ABOVE ROCKHEAD TO VERIFY RECORDS

TERMINATE AT 2xWL. CHECK THE FLOW CHART OF TERMINATION CRITERIA

YES, WITH NORMAL CHANGE IF CHANGE IN GRADIENT OBSERVED

e.g. AT POINT C, SET TERMINATION LOAD TO 95% OF ONE READING LESS WHICH IS AT POINT B.

APPLY SET CRITERIA FOR DOWNGRADED TERMINATION LOAD

INSPECT IF PILE IS IN GOOD CONDITION (SEE STANDARD PROCEDURE)

NO, CONTINUE JACKING

CONSULT ENGINEER TO CHECK IF DOWNGRADING IS REQUIRED

YES, WITH ABNORMAL CHANGE

TERMINATION AT 2x WL

2) FLOW CHART OF TERMINATION CRITERIA

Once reach intended load

1st SetJack: 2 x WL or Downgraded LoadHold: 20 SecondsCheck Settlement : <2mmRelease Load

2nd SetJack: 2 x WL or Downgraded LoadHold: 20 SecondsCheck Settlement : <2mmRelease Load

3rd SetJack: 2 x WL or Downgraded LoadHold: 20 SecondsCheck Settlement : <2mmRelease Load

PASS

NOT OKOK

OK

FOR EACH SET STAGE

1) Before apply load4) Release Load

3) Hold 20 Seconds2) Apply 200% WL

<2mm

Wait 3 minutes

Wait 3 minutes

REFER TO THE PROCEDURE TO OBSERVE AND RECORD PILE HEAVING AFTER INSTALLATION

Change in Gradient

BA

C

*Change in Gradient (A‐B, B‐C)

95% OF LOAD AT POINT B

NORMAL ABNORMAL

3) STANDARD PROCEDURE FOR PILE INSPECTION OF DOWNGRADED PILES TO INSPECT POSSIBLE SIGNS OF DAMAGE

SHINE A TORCH‐LIGHT THAT IS TIED TO A MEASURING TAPE THORUGH THE CENTRAL ANNULUS OF SPUN PILE.

PILE CONSIDERED ACCEPTABLE ‐MEASURE THE DEPTH OF ‘DEFECTS’. ‐USE CAMERA FOR VIDEO RECORDING. (IFCONDITION PERMITTED)

YESNO

INSPECT THE LOCATION OF ‘DEFECTS’

RECORD THE FOLLOWING INFORMATION:‐I) Type and size of spun pileII) Jacking pressureIII) Length of pile installed IV) Number of pile sections and its individual lengthsV) Depth of defectsVI) Direction and orientation of the defects or tilting direction of

damaged pile segmentVII) Any observation of water seepages, rise of water or soil debris

inside spun pileVIII) Photograph records of internal an external pile conditionsIX) Possible mechanism of breakage

REFER TO THE PROCEDURE TO OBSERVE AND RECORD POSSIBLE PILE HEAVING AFTER INSTALLATION

PILE TERMINATED AT DOWNGRADED LOAD

ENGINEER TO ASSESS ACCEPTABILITY OF PILES

4) PROCEDURE TO RECORD POSSIBLE PILE HEAVING AFTER PILE INSTALLATION

CHECK THE PRECISE LEVELLING OF PREVIOUSLY INSTALLED PILES TO DETERMINE ANY HEAVING OF PILE OBSERVED

INDICATE THE PRECISE LEVEL OF THE SPUN PILE

INSTALLATION OF SPUN PILE COMPLETED.

LEVELLING STAFF SHALL BE LOCATED OVER THE TOP SURFACE OF CUT PILE

LEVEL

CUT OFF

AFTER THE LAST PILE WITHIN THE SAME GROUP HAS BEEN INSTALLED

Future R&D

Real‐Time Monitoring System• Laser Distance Ranging Measurement

• Independent Precise Level Measurement (for Rate of Pile Penetration at Termination)

• Higher scanning frequency data logger for timely response & pile creep measurement during load holding for pile termination and MLT

• Automation jacking control regime to prevent structural damage to piles

Jack‐In Hydraulic System• Pressure Control Hydraulic System (against existing constant fluid discharge pump system)• Pressure regulatory chamber (Air‐Fluid Phases)• Variable relief valve and back flow system• Low flow & high pressure pump

• Load Holding for MLT


Automation Control System

• Operational Criteria to Control Jacking• Rate of Jacking penetration• Threshold of Jacking Load Reduction• Rejacking Load for Downgrading Pile Capacity

Future R&D

Laser Detection & Ranging System Jack‐In Hydraulic System


http://www.dynexhydraulics.com/cbpump.htm

Learning &Application of Multi‐Engineering Disciplines• Geotechnical & Structural Engineering : Knowledge in Problem Identification and Solution

• Electronic & Mechanical Sensors : Means to achieving Measurements in Jacking Operation

• Hydraulic System in Mechanical Engineering : To expand Capability of Jacking Operation to performing Maintain Load Test

• System Control : Criteria Management for Potential Automation Control

• Psychology : Friendly Interaction between Human & Machine

July 22, 2012 Footer text here26

Case History• Site Area : 2.5 Acres

• 2 Blocks of 18‐Storey Towers (250 Units)


Ground Conditions• Mine Tailing Materials of Clayey SILT/Silty SAND

• SPT‐N : 5 to 20

• Limestone Bedrock : 16 to 40m bgl

• Groundwater : 3m bgl


Compliance Foundation Design• Bored piles and spun piles, with bored piles used at locations with large loads and where there are cavities


Alternative Foundation Design

• Key Objectives•Optimise Cost•Complete Foundation Construction in 100 days


Alternative Foundation Design• Change all Bored Piles to Class B Jack‐in Spun Piles

• Simplify Construction Works• Less Congestion on Site & Noise Pollution• Reduce Mobilisation Cost• Proof Loading every Piles

• Remove Pointed Pile Shoe & Open Ended• Less Lateral Soil Displacement• Allow Installation of Underpinning Micropile if needed

• Reduce Type of Spun Pile Sizes• Only 400mm & 500mm Spun Piles for Better Efficiency• Streamline the Jacking Operation


Pile Injection Trial Tests

PLT1

• Without instrumentation

• To verify maximum pile capacity

• The jacking load during installation was recorded manually at this stage as the real‐time monitoring device was not ready for the test pile installation.

PLT2

• with instrumentation using the Global Strain Extensometer (Glostrext) system

• to measure the movement of pile segments for global axial strain, load transfer behavior during jacking and also interpreted locked‐in/residual stress in the pile after the unloading cycle


Findings from PLT1 & PLT2

• Pile geotechnical capacity achieved for a 500mm diameter pile is much less than its structural capacity as in PLT2

• Existing weak ground condition does not permit jacking rig to take excessive reaction weight

• Hence, a smaller 400mm diameter pile with working load of 1,200kN was proposed


Final Alternative Pile Design


Pile Layout


Construction –Timing


Construction – Reduced Cooling Time After Welding• Thermal imaging to compare the rate of reduction in temperature of a naturally ventilated weld compared to one with forced ventilation using blower fan


Construction – Reduced Cooling Time After Welding• Cooling time reduced from 30min to 5min

• Production rate increased from 4 to 7 piles / rig / day


Daily Piling Production


Review of As‐built Statistics• 336 piles with capacities downgraded, out of which 305 piles have capacities > 2/3 original capacities

• 96 piles (8%) added to compensate for downgraded piles

• Pile wastages ~ 10%


Conclusions & Recommendations of Case Study• Case study on successful implementation of jack‐in pile system in limestone geology for two 18 storeys tower blocks

• Use of real‐time monitoring during jacking operation has enabled higher utilization factor and minimize risk of overstressing the piles

• Shorter cooling period for welding

• Achieve both Time & Cost Savings


Final Concluding Remarks• Technology advancement is possible if engineer is able to procure and practise a multi‐disciplinary knowledge. i.e. based on fundamental principle of mechanics & physics.

• Innovations : Use of ICT & Technology for Rapid Feedback Control in Automation to attain High Efficiency & Effectiveness of Construction

• Improvements : Construction Methodology, Materials, Workmanship

• Benefits : Faster, Less Wastage, Greener Construction, Better Assurance in Performance, Better Cost Economics, Less Human Errors


Engineering Process CycleStep 1 Design

Objectives

Step 2Problem

Identification

Step 3Option

Exploration

Step 4Execution of Solution

Step 5Performance Feedback


Thank You

Documents

Automated Recording System for Jack In Pile-Final Recording S… · · 2015-11-19. Learning &Application of Multi‐Engineering Disciplines • Geotechnical & Structural Engineering