CLASSROOM @ H.O.PILE LOAD TEST BY P.S.BANSOD 3 rd May 2013 21 June 2013 CLASSIFICATION OF PILES ACCORDING TO METHOD OF CONSTRUCTION • DRIVEN PILES (DISPLACEMENT PILES ) • BORED –CAST-IN-SITU (REPLACEMENT PILES ) DRIVEN PILES 1. Timber, steel, precast concrete, piles formed by driving tubes or shells and then casting concrete 2. Driven piles cause displacement and disturbance of adjacent soil 3. Driving can be done by repeatedly raising and dropping a weight on the pile head or anvil or in favorable conditions vibration can be used. DRIVEN PILES • • • • • DRIVEN TIMBER PILES DRIVEN STEEL PILES DRIVEN CAST-IN –SITU CONCRETE PILES DRIVEN PRE-CAST –CONCRETE PILES DRIVEN –CONCRETE –PIPE PILES Driven Piles A) timber or precast reinforced concrete, b) steel h pile, c) precast concrete shell pile, d) concrete pile cast as driven tube withdrawn (slip form) SHAFT CONSTRUCTION 1. Soil removed by boring or drilling to form a shaft 2. Concrete cast in a casing or without casing – depends on soil conditions 3. Tip can be expanded by under reaming 4. No disturbance to surrounding soil Shaft Construction Craig, 6th Ed. e) Bored pile (cast in-situ), f) Underreamed Bored Pile (cast in-situ) Ultimate Load, Qf Qf = Base Resistance + Shaft Resistance area of pile tip x pressure at tip area of shaft x frictional resistance of shaft Qf = qfAb + fsAs where qf = ultimate bearing capacity of soil at base tip of pile Ab = cross-sectional area of pile at base tip fs = skin friction between pile and soil As = surface area of pile shaft DRIVEN TIMBER PILES • 200MM Ø, 250 MM Ø,300MM Ø OR 200MM X 200 MM X10 M LONG 250MM X 250 MM X10 - 12M LONG 300MM X 300 MM X12 M LONG Length can be increased by splicing . POPULAR FOR RESIDENTIAL CONSTRUCTION IN SCANDINAVIAN COUNTRIES ,USA DRIVEN STEEL PILES • • • • DIAMETER RANGE FROM 600mm - 1874mm LENGTHS RANGE FROM 20m - 70 m WALL THICKNESS RANGE FROM 12mm-40mm GENERALLY PREFERRED FOR MARINE STRUCTURES IN MIDDILE EAST COUNTRIES EUROPE, USA ,SOUTH EAST ASIA and some AFRICAN COUNTRIES. • USE OF STEEL LARGER DIAMETERS WILL BE POPULAR IN FUTURE . AFCONS EXPERIENCE IN STEEL PILES . PARADEEP PORT PROJECT ORISSA -1997- 1998 NAGAPATTINAM JETTY PROJECT(TN) -1999-2000 SHELL –HAZIRA PROJECT(GUJRAT) - 2003-2004 MADAGASCAR JETTY PROJECT - 2007-2008 MAURITIUS CRUISE BERTH PROJECT - 2009 SOHAR BULK JETTY PROJECT(OMAN) -2010-2011 LNG JETTY AT DAHEJ(GUJRAT) - 2011-2013 AFCONS EXPERIENCE IN DRIVEN PRE-CAST-CONCRETE PILES 1.ADEN FLOUR MILL PROJECT –YEMEN (20042005) 2.PRECAST –CONCRETE PILES OF 450mm Ø HAD TO BE MOBILIZED FROM MALAYSIA THESE CANNOT BE DRIVEN IN DENSE SANDS WITH N> 60 OR WITH DENSE GRAVELLY SANDS. DRIVEN CAST –IN-SITU CONCRETE PILES • • • • • • DIAMETER RANGE FROM -300mm – 760 mm LENGTH RANGE FROM -20m -26 m CAPACITIES RANGE FROM -30T-120T VERY FAST CONSTRUCTION POSSIBLE TYPICAL CONSTRUCTION TIME 20-30 MIN/PILE HEAVY CRANE & PILE DRIVING HAMMERS ARE BASIC REQUIREMENTS . • GENERALLY PREFERRED IN COHESION LESS SOILS LIKE SILTY SANDS OR FINE SANDS OR GRAVELLY SANDS . TYPICAL RANGE OF DESIGN LOADS FOR PILES DIAMETER mm AXIAL LOAD (COMPRESSION ) IN T LATERAL LOAD IN T TENSION LOAD @60% COMPRESSION IN T 300 mm 30 500 mm 60 600 mm 120 760 mm 200 900 mm 360 1000 mm 400 1200 mm 500 1300 1500 mm mm 550 700 18 36 3 70 4 120 5 210 8 240 10 300 12 330 15 420 TYPICAL RANGES OF DESIGN LOADS FOR VERY LARGE DIAMETER PILES DIAMETER mm AXIAL LOAD (COMPRESSION ) IN T TYPE OF PILES 1600 1800 2000 2400 2500 3000 450 900 650 750 1000 2000 CONCRETE PILES STEEL PILES CONCRETE PILES CONCRETE PILES CONCRETE PILES CONCRETE PILES TYPICAL EXAMPLES LNG JETTY COCHIN SOHAR BULK JETTY RAJIV GANDHI BRIDGE BANDRA BY HCC GANGA BRIDGE BAKHTIARPUR BY NEC MEGHINA BRIDGE BANGLADESH TENDER MTHL BRIDGE MUMBAI TENDER BY AFCONS BY AFCONS TYPES OF PILE LOAD TESTS INITIAL LOAD TESTS : ON NON WORKING PILES FOR 2 TIMES X DESIGN LOAD 2.5 TIMES X DESIGN LOAD 3 TIMES X DESIGN LOAD FOR AXIAL LOAD CAPACITY (COMPRESSION) HORIZONTAL LOAD CAPACITY (LATERAL LOAD) UPLIFT LOAD CAPACITY (TENSION) TYPES OF PILE LOAD TESTS ROUTINE PILE LOAD TESTS ON WORKING PILES FOR 1.5 TIMES * DESIGN LOAD FOR AXIAL LOAD CAPACITY (COMPRESSION) HORIZONTAL LOAD CAPACITY (LATERAL LOAD) UPLIFT LOAD CAPACITY (TENSION) TYPICAL COMPRESSION LOAD TEST • • • • • • Typical Case of 1200mm Φ pile Design Load -400 T Type of Test – Initial Test Load – 400 T X 2.5 = 1000 T Required reaction load – 1000 T+250 T = 1250 T Ground Condition – on land 3 WAYS OF CONDUCTING THE TEST • BY KENTLEDGE METHOD UP TO 900 TO 1000 T • BY REACTION PILES METHOD FOR HIGHER LOADS • BY REACTION ANCHORS METHOD WHERE ROCK IS ENCOUNTERED AT SHALLOW DEPTHS KENTLEDGE METHOD • Main Requirements 1.Test Girder – Primary Girder 2.Load Distribution Girders – Secondary Girders 3.Grillage Beams for uniform transfer of loads 4.Concrete Blocks – For 1250 T kentledge and for support of girders. 5.Hydraulic Jacks of total 1500 T capacity 6.Dial Gauges – 8 nos. of 50mm range and 0.01 mm least count. STEPS IN CONDUCTING LOAD TEST 1 1. Construct test pile 2. Prepare pile head for test arrangement 3. Erect supports for girders at a distance of 2.5 X dia of pile from center of pile 4. Ensure that surrounding ground is strong enough with SBC of 20-25 T/m2 where concrete blocks for supports are being arranged STEPS IN CONDUCTING LOAD TEST 2 5.Place required no of hydraulic jacks symmetrically on top of test pile. 6.Place grillage beam on top of hydraulic jacks 7.Arrange supports for primary girder 8.Place primary girder on top of grillage beam, while maintaining a gap of at least 100mm between them STEPS IN CONDUCTING LOAD TEST -3 9.Arrange supports for secondary girders using timber beams or concrete blocks at required place where ground is strong enough with 25 T/m2 SBC 10.Arrange concrete blocks on top of secondary girders, systematically in a layer by layer manner 11. Follow the methodology/ drawings provided by design department/CPMG while arranging the concrete blocks in layers 12.Arrange datum bars in the vicinity of test pile using brick/concrete pillars or timber blocks 13.Fix 4 nos. of dial gauges on the test pile symmetrically with help of magnetic base clamps STEPS IN CONDUCTING LOAD TEST-4 14.Arrange power pack at a sufficient distance from the test pile. Connect all the hydraulic jacks to the power pack. Check for leakages at jacks, power pack etc. 15.Conduct the load test as per pre determined loading and unloading sequence 16.Maintain each load for a sufficient time, till rate of settlement of pile drops down to 0.125mm /30min 17.Take readings of settlement of all dial gauges during loading and unloading of pile STEPS IN CONDUCTING LOAD TEST-5 18.Compile field observations of Load/settlements in a systematic tabular manner. Take signatures of client/consultant’s representative on all the date recording sheets 19.Prepare a graph of load versus settlement from the field observations 20.From the graph estimate the load corresponding to 12mm settlement and 120mm settlement (if observed in the load test) STEPS IN CONDUCTING LOAD TEST-6 21.As per IS : 2911( Part 4), safe load is defined as the latest among the following two criteria a. 2/3 of the load at which pile attains a total settlement of 12mm b. ½ of the load at which pile attains a total settlement of 120mm 22. Prepare a systematic report on pile load test incorporating field observations, load Vs settlement graphs and interpretation of test result. STEPS IN CONDUCTING LOAD TEST-7 23. Remove dial guages ,hydraulic jacks, power packs from the test site . 24.Remove concrete blocks systematically from top to bottom ,remove secondary girders . 25.Remove primary girders . 26.Remove supporting concrete blocks . 27.Back fill the excavated pit around test pile and restore the ground to original condition . STEPS IN CONDUCTING LOAD TEST-8 28. Store hydraulic jacks and power packs ETC ,in well maintained condition in stores . 29. Store primary girders ,secondary girders and grillage beams in neatly arranged manner in stores . 30. Store concrete blocks ,wooden sleepers and other accessories in neatly arranged manner in stores . ADVANTAGES OF PILE LOAD TEST 1. Being used in India for last 60 years 2. Being used all over world for last 80 years 3. Sequence of loading simulates real life loading behavior of piles 4. One of the best way of assessing load displacement behavior of pile 5. Confirms the design of pile 6. A tool for ensuring quality assurance of pile construction LIMITATIONS OF STATIC LOAD TEST 1. Large space requirement (Approx. 12m X 12m in plan) 2. For kentledge method setting time 10 days 3. For reaction pile method setting time 30 days 4. For reaction anchors method setting time 30 days 5. Special fabrication of girders required 6. Quite a large cost involved Alternative Methods to Static Load Test 1. High Strain Dynamic Pile Load Test 2. Osterberg Load Cell Test • LOAD TEST PHOTOS OF NAD AL SHEBA RACE COURSE, DUBAI Load test by Kent ledge method Load test by Kent ledge method Nad Al Sheba Race Course, Dubai, Load settlement curve for TP2 LOAD SE TTLE ME NT CURVE FOR INITIAL PILE LOAD TE ST (TP2 M DN-1A) ON 1200m m DIA TE ST PILE AT NAD AL SHE BA RACE COURSE , DUBAI Applie d Load in Tons 0 0.00 -0.40 -0.80 200 400 600 800 1000 Observed Settlement of Pile (mm) First Cycle -1.20 -1.60 -2.00 -2.40 -2.80 -3.20 -3.60 -4.00 1. TOTAL SE TTLE ME NT = 1.54mm 2. NE T SE TTLE ME NT = 0.06mm 3. E LASTIC RE BOUND = 1.48mm Second Cycle Third Cycle RESULTS OF THREE CYCLES Load settlement curve for TP4 LOAD SETTLEMENT CURVE FOR INITIAL PILE LOAD TEST (TP4 MDN-3) ON 1200m m DIA TEST PILE AT NAD AL SHEBA RACE COURSE, DUBAI Applied Load in Tons 0 0.00 -0.40 -0.80 Observed Settlement of Pile (mm) 200 400 600 800 1000 First Cycle -1.20 -1.60 -2.00 -2.40 -2.80 -3.20 -3.60 -4.00 1. TOTAL SETTLEMENT = 3.74mm 2. NET SETTLEMENT = 0.07mm 3. ELASTIC REBOUND = 3.67mm Second Cycle Third Cycle RESULTS OF THREE CYCLES Nad Al Sheba Race Course, Dubai, SUMMARY OF PILE LOAD TESTS Test No. TP-2 TP-4 Pile Length 26.0m 17.55m Total Net Elastic Test Load Settlemen Settlemen Rebound t t 922.4T 1.54mm 0.06mm 1.48mm 930.3T 3.74mm 0.07mm 3.67mm MARINE PILE LOAD TEST-3 USING SAMRAT JACKUP AT DAHEJ SITE MARINE PILE LOAD TEST-3 USING SAMRAT JACKUP AT DAHEJ SITE • • • • • • • PILE DIAMETER PILE DIAMETER PILE TOP LEVEL TEST PLATFORM LEVEL PILE TOE LEVEL DESIGN AXIAL LOAD TEST LOAD 1422MM (OD) 1358MM (ID) +16.7 M C.D +13.2 MC.D -43.5 M C.D 8000 KN 12000 KN MARINE PILE LOAD TEST-3 USING SAMRAT JACKUP AT DAHEJ SITE • • • • • • HIGHEST WATER LEVEL LOWEST WATER LEVEL DEPTH OF WATER SEA BED LEVEL SCOUR DEPTH CURRENT AT TEST LOCATION +10.5 m C.D - 1 m C.D 19.7 M (-14.6 M C.D) -26.6 M C.D 6 KNOTS • LOAD TEST RESULTS OF BARRAPULLA DELHI Applied Load (T) 0 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 1200 1ST TO 4TH CYCLE 5TH CYCLE 6TH CYCLE SETTLEMENT (mm) 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00 7TH CYCLE 8TH CYCLE 9TH CYCLE LOAD Vs SETTLEMENT OF 1200 DIA PILE AT BARAPULLA 10 TH CYCLE Barrette pull out test at Chennai central THANK YOU FOR YOUR PATIENT HEARING AND ATTENTION .