Piling Work

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Tables of Contents

1. Pile Driving Work (Normal)

1.1 Pile Specification

1.2 Trial Pile Driving Test

1.3 Pile Driving Work

1.4 Handling Pile Head

1.5 Site Steel Pipe Pile Welding

1.6 Handling and Storing Piles

1.7 Changing Design

1.8 Pile Scrap Recycle Standard

1.9 Other

1.10 Reference

1.11 Transportation

1.12 Storage

1.13 Provisional driving criteria

1.14 Final driving criteria

1.15 Construction Report

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1. Pile Driving Work (Normal)

1.1 Pile Specification

1.1.1 Steel Pipe Pile

(1) For the steel pipe pile dimensions, refer to Appendix 1 『Steel Pipe Pile Manufacturing Specification』 of

this specification.

1.1.2 PC Pile (Pre-tension-way Centrifugal Pre-stress Concrete Pile)

(1) Pre-stressed concrete pile shall conform to JIS A 5335 or equivalent..

(2) Refer to the following table for the permissible tolerance for pile specification.

ClassificationPermissible Tolerance

D300 - D600 D700 - D1200

Length ±0.3% of the Pile Length

Outer Diameter + 5mm, - 2mm + 7mm, - 4mm

Thickness + Not Specified, - 1mm

1.2 Trial Pile Driving Test

1.2.1 Performing Trial Pile Driving Test

Before commencing the pile driving work in full scale, perform trial pile driving test. Comply with the instruction of

the supervisor or the inspector for the number of piles and the specification each area.

1.2.2 Selection of the Location for Trial Test

Location of all piles shall be set out at the points designated on the construction drawings.

1.2.3 Record of Trial Pile Driving Test

Using the equipments indicated in the design for trial driving test, perform pile driving test and check the Pile

Driving Record. The record of penetrated depth, dropping times per 50cm of hammer, cumulated times of

drop, average penetrated depth per 50cm and rebound curve is necessary using the equipments indicated

in the design document for trial.

1.2.4 Confirming Trial Pile Driving Test

For the test, drive the pile until the final bearing strata and compare and confirm with the boring data.

1.2.5 Adjusting Pile Specification

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The constructor shall review the result of the test to determine pile length and combination and before

procurement purchase and also examine whether or not the required bearing capacity is secured and

determine whether it is necessary to change pile specification by consulting with the supervisor or the

inspector.

1.3 Pile Driving Work

1.3.1 Preparation

Pile driving equipment and hammer shall be subject to review and approval by Supervisor, prior to mobilization.

The driving equipment, hammer and hammer cushion shall be selected to achieve the required pile

penetrations and capacities without pile damage. Unsuitable hammer discovered during piling operations

shall be replaced with a suitable hammer.

(1) Once pile driving is started, it shall be continued without interruption, except for splicing, until the pile has

been driven to the specified driving criteria.

The driving criteria shall be evaluated and resived by Supervisor based on the pile - driving data to the

early stages of piling and pile load tests, then it shall be used as the control measure for driving.

(2) Piles shall be placed as accurately as practicable within the tolerance in location and driven to the lines

shown on the engineering drawings. The driving equipment and pile shall be maintained accurately in

position during driving.

(3) During driving pile butt ends shall be protected by means of cushion made of hard dry timber. Type of the

cushion shall be approved by Owner prior to use.

(4) Piles shall be driven with fixed leads which will hold the pile in the proper position and have proper axial

alignment with hammer.

(5) In the following cases contractor shall report to Supervisor to determine the measures to be taken.

- When practical refusal is achieved at a tip elevation less than specified.

- When specified pile driving criteria is not achieved at the specified tip elevation.

- When obstructions are encountered during pile driving.

(6) For piles damaged below the cut-off elevation during driving or not driven within tolerances set forth below,

measures shall be immediately taken which may include repair of pile or otherwise instructed by

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Supervisor.

(8) Pile groups shall be driven from the interior outward to preclude densification and excessively hard driving

conditions on the interior.

(9) The Contractor shall plan the pile driving work so that harmful disturbance of the adjacent existing facilities,

structures, etc. does not occur by the pile driving operations and shall report to Owner to get his approval

prior to commence the work.

(10) In case it is necessary to provide advance hole before driving, due to the following conditions below, the

contractor shall report to Supervisor to get his approval prior to commence the work.

- In case there have been predetermined of the pile lengths from the static calculation then to achieve a

certain designed working load, in clay the diameter of the advance hole should not greater than 75% of the

pile size and in sands should not exceed 50% of the pile size. To obtain the full design length, the advance

hole should be stopped at least 3.0 meters above the designed penetration.

- In case it is necessary to minimize displacement in soft clay layer, and controlling the pile heave caused

by volume displacement the diameter of the advance hole drilled should not greater than 75% of the

outside size of the pile and at least 150 mm less than pile size.

- In case to anticipate the pile heave, it is necessary to establish a benchmark survey after the piles are

driven.

(11) Markings

Markings shall be made with spray paint at intervals over the entire pile length and figures shall be painted at

these intervals starting from the bottom of the pile. The top one-third of the pile shall be marked at 25 cm

intervals, bottom two-thirds at 50 cm intervals.

(12) Sequence of pile driving

The sequence of pile driving shall be planned so that harmful displacement of installed piles does not occur by

other pile driving operations.

(13) Blow count measurement

Blow count per every 100 cm marks shall be recorded for at least the final ten (10) blows rebound and ram fall

height shall be measured and recorded..

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1.3.2 Performing Pile Driving Work

(1) Diesel Hammer

An appropriate combination of equipment for pile driving work by pile diameter is shown in the table

below. The equipment described in the design documents shall be used on a priority basis; in case of a

need to change such equipment due to the difference between the design conditions and actual ground

conditions, however, approval from an inspector or a supervisor shall be obtained.

▶Appropriate combination of equipment for pile driving work by pile diameter (diesel hammer)

(2) Hydraulic hammer

Select the proper size for the hammer considering the pile length and soil conditions. The following are the

general criteria for selecting the hydraulic hammer:

Pile Diameter Diesel Hammer Crawler Crane

Conc. Pile φ400.0 ~ φ1000.0 - -

It is plan that decide by loading test.

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▶Criteria for selecting equipment by pile diameter (hydraulic hammer)

▶Criteria for adjusting the equipment dimensions

- Concrete pile: Raise the pile one level higher if the pile driving length is more than 10m and the earth

layer with N value of more than 30 is more than 3 m deep.

(3) Pile driving

In principle, pile driving shall be performed in the presence of an inspector or a supervisor . After

conducting trial driving for two or three times, adjust the leader a second time to make sure that the error in

perpendicularity of the pile is ±0. Continue driving the pile if it is proven to be driven perfectly following a

reexamination with the inspector or supervisor’s permission. Continue inspecting the perpendicularity of

the pile until the driving has been finished to ensure that its vertical position is maintained. Should the

slope of the pile exceed the permissible tolerance, stop the driving, adjust it, and restart the work.

▶Permissible tolerance for the perpendicularity of the pile during driving: 1/100 (0°34＇22.58＂)

▶Directions for pile driving using a hydraulic hammer

The ram falling height shall remain under 0.5m (driving with great force into the soft ground can cause the

pile to deviate significantly from its perpendicular position; thus making adjustment difficult).

(4) Deflection during pile driving

In case of deflection or damage to nearby piles while driving, measure the degree of deflection or other

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Pile

driv

ing

leng

th (

m)

Pile

driv

ing

leng

th

Pile driving diameter

Pile driving diameter(mm)

changes and report the result to the inspector or supervisor for appropriate instructions and take the

necessary measures.

(5) In case of expected damage to adjacent structures

(A) Driving shall start with the place nearest to the adjoining structures.

(B) Slow down during driving.

(C) If necessary, dig a pile hole in advance for pile insertion.

(D) Dig a hole when necessary to reduce earth pressure.

1.3.3 Completion

(1) Permissible Tolerance after Completing the Driving

Unless otherwise specified on the engineering drawings the following tolerance values shall be

acceptable.

▶ Central Space of Pile Head: Within ± 10cm

▶ 1 cm in 100 cm along the longitudinal axis of the slope for batter pile.

1.3.4 Record of Driving Pile

Record the date, pile number, pile specification, pile length, pile combination, number of driving, driving times,

welding time, rebound curve, and scrap length, etc. and keep the record.

1.4 Handling Pile Head

1.4.1 Cutting Pile Head

When the driving completes, cut the pile horizontally to the designed height as indicated in the design document.

Gas cutter is used for steel pipe pile, make sure to install the gas backfire protector for safety before cutting

the pile. Fill inside the pile with earth as soon as cutting the pile.

▶ Pile Top Elevation Permissible Tolerance: Within ± 1cm

Extended pc tendons shall be provided for pc pile as shown on the standard drawing.

Suitable means and tools, which subject to Supervisor approval, shall be used for cutting the pc piles in

order to prevent the pc piles from damage during pile cutting.

1.4.2 Reinforcing Pile Head

After filling inside the pile, reinforce the pile head according to pile head reinforcement standard drawing.

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(Refer to Civil Design Standard Drawing C01-0101)

Contents of the construction method concerning the length of pile head reinforcing bar, and the compression and

pulling out transferred to the foundation when reinforcing steel pile head

(1) Contents

ClassificationSteel Making Plant

PILE DIAAXIS-BAR

HOOP-BAR Lr (mm) Ls (mm)

PC Pile D 400 14-HD16 9-HD13 600 -

PC Pile D 500 16-HD16 9-HD13 600 -

PC Pile D 600 18-HD16 9-HD13 600 -

1.4.3 Disposing Scraps

The scraps produced during the construction shall be transported or returned to the designated location, and the

quantity must be more than 70% of the total (quantity of scraps generated due to additional factor).

1.5 Site Steel Pipe Pile Welding

1.5.1 General

(1) Contractor shall submit detailed welding procedures and welder qualification test record to Supervisor for

written approval prior to commencement of the work.

(2) Welder engaged in this work shall be qualified in accordance with ANSI/AWS D1.1 or ASME Section IX(refer

to section 7.1.(3) and 7.1.(4). Required welding position for qualification shall be 6G or 2Gand 5G.

(3) In principle, welding procedure and welder qualification test record which have certified in accordance with

ANSI / AWSDl.1.

(4) Alternatively, welding procedure with its supporting PQR(Procedure Qualification Record) and welder

qualification test record which have been certified in accordance with ASME Section IX, may be substituted for

section 7.1.(3).

(5) The welding procedure and welder qualification test records shall form a part of this specification.

(6) Other requirement of pile splicing for pre-stressed concrete pile from Manufacturer (refer to attachment-1).

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1.5.2 Welding

(1) All welding joint for steel or pc pile shall be full penetration groove weld. When splicing of two pipe piles, the

end of pipes to be joined shall be aligned as accurately as practicable within exiting commercial tolerances on

diameters, and out-of roundness.

(2) Edge of welding joints .shall be in accordance with section. 3.2 ANSI/AWS D1.1 after brushing and/or grinding

to remove scale, slag, rust, grease and any other foreign materials.

(3) Welding shall not be allowed when the surface of welding joints are wet, exposed to rain or heavy wind.

(4) For SMAW(Shielded Metal Arc Welding) Process, only low hydrogen type electrode (AWS class SFA 5.1, E

7016 or E 7018) shall be used. Other welding materials such as high cellulose type or illuminate type shall be

prohibited.

(5) Low hydrogen type electrode mentioned in section 7.2 (4) shall be dried at oven at the temperature of 3000 to

4000C,1 hour, before being used. Drying more than two times shall be prohibited.

(6) After driving mentioned in section 7.2 (5). Each welder shall hold low hydrogen type electrodes in portable

dryer at the temperature of 1000 to 1500 C to prevent from absorbing additional humidity.

(7) Prior to welding on previously deposited metal, all slag shall be removed from the weld and the adjacent base

metal shall be grinder smoothly and brushed clean.

1.5.3 Inspection

(1) All weld shall be visually inspected in accordance with the acceptance standards and requirements of

ANSI/AWS D1.1 section 8.15 "Quality of Weld" and section 3.6 "Weld Profile". Also the weld shall not have

any cracks, undercut exceeded 0.8 mm depth, exposed surface porosity, and slag inclusions.

(2) LPT (Liquid Penetration Test) shall be performed at the rate of 10% minimum for random locations, but subject

to change depending on welding production performance.

1.5.4 Remarks

If any deviations from these requirements of these specifications arise, the contractor shall submit his proposal to

Supervisor.

1.6 Handling and Storing Piles

1.6.1 Steel Pipe Pile

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(1) Take cautions when storing and transporting steel pipe pile to prevent permanent deformation due to self-

weight or shock.

(2) To store piles, select a place with good drainage and firm ground, grade the land evenly, and lay props in short

intervals.

(3) For each bundle of pipes, prop them in the same position and do not heap up more than 10 piles on top of

another.

(4) When loading or unloading steel pipe piles tie two points and handle them keeping horizontality.

1.6.2 Concrete Pile

(1) To relieve shock while transporting, wind cushioning material on both ends and in the center of pile.

(2) To protest damages to piles while transporting, install sleepers on the floor, fix wedges, and tie them firmly with a

rope. In case stockpile more than 2 layers, the sleeper of each stage shall be placed in the same position

vertically.

(3) The following shows the position of the sleeper when transporting piles.

(4) The position of the rope shall be as follows when loading and unloading.

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(5) To store the piles, select a well drained and firm ground, grade the ground evenly, and lay sleepers in a short

interval.

(6) Do as follows to erect the pile for pile driving work.

(A) Centrifugal Reinforcing Bar Concrete Pile

(B) Centrifugal Prestress Concrete Pile

(C) Piles Longer Than 15m

1.7 Changing Design

1.7.1 In case the values applied in the design document are different from results of the geotechnical

survey of the actual ground, can change the design by obtaining the approval from the supervisor

or the inspector.

1.7.2 The pile driving length must be changed to the actually driven length.

1.7.3 If it is acknowledged that the excavation and actual circumstances of the site brought noticeable difference will

standardized additional factor 5% after piles are driven, provide supporting data and change design.

1.7.4 To recycle scraps of the pile generated from excavation after piles are driven, refer to the Pile Scrap Recycle

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Standards, and the design can be changed by obtaining the approval from the supervisor or the inspector.

1.7.5 The supervisor or the inspector must consider pile bearing capacity and the importance of the structure when

approving the recycling of piles.

1.8 Pile Scrap Recycle Standard

1.8.1 Application Scope

This paragraph is applied to producing a recycled pile by cutting, fabricating and welding steel pile scraps. In case

of using 1 scrap piece as upper pile and lower pile, manufacture piles in conformance to the upper pile and

lower pile production standards of the Steel Pipe Pile Manufacturing Specification.

1.8.2 Pile Recycling

- Work Flow

- The inner and outer side of the pile scrap to recycle must have no harmful defects.

- The entire length of the recycled pile must be straight, and both ends should be nominal direction against

central axis of pile and flat without rugged surface.

- When recycling the steel pipe pile, work on the worktable where the straightness of the pile as well as the

welding process can be easily controlled.

- To use the completely recycled piles as top, middle and bottom piles, both ends must be produced according

to the Steel Pipe Pile Manufacturing Specification (Standard Specification).

1.8.3 Inspecting Recycled Pile

The supervisor or the inspector can perform non-destructive test for the welding plane and change design.

1.9 Other

1.9.1 After driving piles and until filling inside the pile, check the water level inside the pile hole once a day in the

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Collection & Storage of Pile Scrap Sorted and Cutting

Beveling & Grinding

Welding Inspection Transportation and Sort out

position designated by the supervisor or the inspector and submits the observation records to the

supervisor or the inspector.

1.9.2 In case there was horizontal displacement in the previously driven pile due to soft ground or abnormal soil

pressure, measure the displacement and other changes and report to the supervisor or the inspector

about the results and obtain their approval to take appropriate actions.

1.10 Reference

The materials, fabrication, and testing shall be in accordance with the latest issue of the following codes and

standard and the following Owner specification, unless otherwise specified herein after

ANSI/AWS D1-1 : Structural welding Code - steel.

ASMES ect. IX : Qualification standard for welding and Brazing Procedure, Welders, Brazes, and Welding

and Brazing Operators.

JIS A 5335 : Pre-tensioned Spun Concrete Piles.

Manufacturer's Standard, if any

1.11 Transportation

Loading and transportation from the delivery place designated by Supervisor shall be carried out under the

subcontractor's responsibility.

Care shall be taken during handling and transportation of piles. Piles damaged during handling and

transportation shall be inspected by Supervisor to determine its acceptance.

1.12 Storage

Storage of piles at the subcontractor's stock yard shall be the responsibility of contractor.

Care shall be taken to prevent corrosion and/or deterioration of pile during storage.

1.13 Provisional driving criteria

Provisional driving criteria is desirable that decide by loading test.

1.14 Final driving criteria

Final driving criteria is desirable that decide by loading test.

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1.15 Construction Report

The Contractor shall keep a complete record for each pile and shall provide the following information on a

daily basis to Supervisor, on the pile driving logs.

▶ Date and start/stop time of each driving operation.

▶ Location, description of foundation, drawing number and pile number (pile numbers shall not be duplicated).

▶ Type and size of pile

▶ Pile hammers used (model, size, weight)

▶ Blow count, per every 1000 mm and total blow count.

▶ Blow count, rebound and ram fall height for final ten (10) blows.

▶ Depth of plug in each section of pipe pile and final depth of plug from cut-off elevation.

▶ Ground surface elevation.

▶ Pile tip elevation when driving is complete.

▶ Observation of ground surface

▶ Cut-off elevation

▶ Pile length

▶ Deviation at cut-off level from correct position.

▶ Special notes if any.

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Ru = 3.0 x A + Nf .............................................. for pc pile

Attachment - 1 Pile Splicing

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Attachment - 2 Quality Control Daily Pile Quality Record

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Attachment - 3 Piling Record

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Attachment - 4 Piling Site Report

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Attachment - 5 Welding Inspection

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