Bored Pile Procedure

ContentBored Pile Procedure : 1. Set up the Location of Bored Pile2. Insert Casing3. Drilling4. Removing Slime5. KODEN-Test6. Insert of Steel Cage7. Insert Tremie Pipe8. Pouring the Concrete9. Removing CasingCycle Time of a Bored Pile

Bored Pile Procedure 1. Set up the location of Bored Pile

Bored Pile Procedure

We use Total Station instrument to survey each pile point.

Bored Pile Procedure2. Insert casing casing must be stand vertical ( by checking verticality of casing when insert casing )

Bored Pile Procedure use Vibrodriver or Vibrohamer to insert casing

Bored Pile Procedure3. Drilling Drilling Machine : weight : 130tons BG - 40 drilling depth : 49m diameter : 3m

weight : 96tons BG - 28 drilling depth : 39m diameter : 2.5m

weight : 91tons SD - 515 drilling depth : 36m diameter : 2.5m

BG - 40BG - 28SD - 515

Bored Pile Procedure4. Removing slimewhen finish drilling , we use Mechanical pump equipment to remove slime .

Bored Pile Procedure 5. KODEN TestKODEN test utilizes the principle of ultrasonic wave travel from sensor to the wall of drilled hole and reflect to the sensor through the bentonite slurry. Equipment KODEN equipment consists of two parts, recorder unit and winch unit .

Recorder Unit Winch Unit

Bored Pile ProcedureRecorder unit controls the operation and record the test result. On the other hand, winch unit lowers the probe (sensor) down the hole for ultrasonic reflection . Testing Procedure

1. Remove any obstacle around the hole area in order that the test equipment can access to the hole .

2. Place the winch unit over the top of drilled hole or on the steel casing. Position the sensor (probe) at the center of the hole .

3. Lower the sensor into bentonite slurry. Hold the sensor at depth approximately 1 to 1.5m .

4. Restore the sensor to the starting position and perform the test.

Bored Pile Procedure Test Result Test results are presented in graphical plot and show characteristics below :1. Profile along two perpendicular axes.

2. Average verticality of the hole.

3. Location or depth where abnormality Occurs such as reduction in diameter,or collapsed wall of the hole.

4. Depth of drilled hole.

Bored Pile Procedure 6. Insert of steel cage

Bored Pile Procedure 7. Insert Tremie

Bored Pile Procedure Type of tremie pipe : we have 3 types of tremie : 1m, 2m and 3m Length

3m Length1m Length2m Length

Bored Pile ProcedureHow to insert tremie pipe :Use mobile crane to hang the hopper Then connect each tremie pipe After that put it into the bored pile hole until bottom

When we pour concrete, we have to burythe tremie pipe into concrete as below :

Diameter of Bored PileBuried Length of Tremie10003 to 3.5m18002 to 2.5m

Bored Pile Procedure8. Pouring the concrete

Quality of Concrete : Max. size of Aggregate : 2.5cm Workability : 55cm ( Flow )

Bored Pile Procedure Strength of concrete : Design strength : fck =300kg/cm ( 28days cure concrete ) Strength of mix ( Target Strength ) : according to the Standard Specifications of Concrete ( Korea Concrete Institute )

Strength of mix ( Target Strength )

So, for Actual Concrete Strength : 400kg/cm

MaterialStrengthCalculation of fck ( Mpa )Strength of mix ( Mpa )Target Strength 21 > fckfck + 7( Standard specifications of concrete )21 fck 35fck + 8.5( Korea Concrete Institute )fck > 35fck + 10

fck300kg/cm = 29.42 MpaStrength of mix29.42 Mpa + 8.5 Mpa = 37.92 Mpa = 389 kg/cm Apply : 400 kg/cm

Bored Pile Procedure 9. Remove casing

Cycle Time of a Bored Pile

Step of Bored PileCycle time of each step ( hour)1. Set up location of Bored Pile0.32. Inserting Casing 23. Drilling84. Removing slime15. KODEN Test16. Inserting Steel Cage27. Inserting Tremie Pipe18. Pouring the concrete29. Remove casing1.5Total Cycle Time 18.8

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