outline of the execution manual for seismic retrofitting of existing pile foundations with high...

Outline of the Execution Manual for Outline of the Execution Manual for Seismic Retrofitting of Existing Pile Seismic Retrofitting of Existing Pile

Foundations Foundations with High Capacity Micropileswith High Capacity Micropiles

Masashi ITANIMasashi ITANITakeshi OSHITATakeshi OSHITA

Seiichi ONODERASeiichi ONODERA

IWM200IWM200３３

Public Works Research InstitutePublic Works Research InstituteConstruction Technology Research Team.Construction Technology Research Team.

Contents of the Executive ManualContents of the Executive Manual3.6.1 Grout Mixture

3.6.2 Weighing and mixing of grout

3.6.3 Initial injection3.6.4 Pressure injection and withdrawal ofHMP steel pipes

4.2.1 Reinforcing materials

4.2.2 Grout

3.4.1 Boring method 4.2.3 Pile head steel pipes

3.4.2 Boring machine and boring tools 4.2.4 Quality control items

3.4.3 Boring

3.4.4 Confirmation of bearing ground

3.4.5 Treatment following boring

4.4 Schedule control

4.5 Safety control

4.6 Conserving enveronment

4.7 Execution records

3.5 Installing reinforcing materials

3.6 Grout injection

3.7 Reinserting HMP steel pipes

3.8 Treatment of the pile head

3.9 Expansion of footing

CHAPTER 4 EXECUTION MANAGEMENT

4.1 Execution management items

4.2 Quality control of materials

4.3 Confirming the bearing capacity of HMP

3.1 Execution process

3.2 Major machinery and equipment

3.3 Preparatory work

3.4 Boring

2.1 Basic items

2.2 Preliminary surveys

2.3 Execution planning

CHAPTER 3 EXECUTION METHOD

CHAPTER 1 GENERAL

1.1 Scope

1.2 Definition of termsCHAPTER 2 GEVERAL ITEMS CONCERNINGEXECUTION

3.6.1 Grout Mixture




4.2.2 Grout



3.4.3 Boring




4.5 Safety control




3.6 Grout injection











3.4 Boring

2.1 Basic items




CHAPTER 1 GENERAL

1.1 Scope


Caputure 1 Caputure 1 ：： GemeralGemeral

This manual covers thThis manual covers the e execution of seismic execution of seismic retrofittingretrofitting of of existing pexisting pile foundationsile foundations using using hihigh capacity micropilesgh capacity micropiles. .

ScopeScope





4.2.2 Grout



3.4.3 Boring




4.5 Safety control




3.6 Grout injection











3.4 Boring

2.1 Basic items




CHAPTER 1 GENERAL

1.1 Scope


3.6.1 Grout Mixture




4.2.2 Grout



3.4.3 Boring




4.5 Safety control




3.6 Grout injection











3.4 Boring

2.1 Basic items




CHAPTER 1 GENERAL

1.1 Scope


Caputure 2 Caputure 2 ：： GENERAL ITEMS GENERAL ITEMS CONCERNING EXECUTIONCONCERNING EXECUTION

Major Items Surveyed in Preparation for ExecutionMajor Items Surveyed in Preparation for Execution

CategoryCategory Survey itemSurvey item

Working environment conditionsWorking environment conditions

Limit on overhead spaceLimit on overhead space

Plane execution yard conditionsPlane execution yard conditions

State of surrounding roadsState of surrounding roads

Existing structuresExisting structures

Adjacent structures and underground structuresAdjacent structures and underground structures

State of rivers etc.State of rivers etc.

Execution groundExecution ground

Temporary equipmentTemporary equipment

Natural conditionsNatural conditions

Surrounding environment Surrounding environment conditionsconditions

State of surrounding regionState of surrounding region

State of nearby roadsState of nearby roads

Legal restrictions on construction workLegal restrictions on construction work

Byproducts of constructionByproducts of construction

Ground conditionsGround conditionsSoilSoil

GroundwaterGroundwater

Preliminary surveysPreliminary surveys

Limit on overhead spaceLimit on overhead space

In order to retrofit an existing pile foundation, In order to retrofit an existing pile foundation, the restriction onthe restriction on the overhead spacethe overhead space imposed imposed byby overhead wiresoverhead wires,, the superstructurethe superstructure,, the beam the beam of the bridge pierof the bridge pier etc.etc.

4m4m

Preliminary surveysPreliminary surveysSurvey of the execution yard conditionSurvey of the execution yard condition

The plane layout of the execution yard must The plane layout of the execution yard must be studied bybe studied by surveying the site boundaries surveying the site boundaries, , structuresstructures and and uses under girdersuses under girders, , areasareas and and locationslocations that can be used as the working yard, that can be used as the working yard, level differences of the ground etc.level differences of the ground etc.

Preliminary surveysPreliminary surveys Survey of adjacent and underground structureSurvey of adjacent and underground structure

Structural specifications of existing structures Structural specifications of existing structures ((existing footings, bridge piers etcexisting footings, bridge piers etc.), structures .), structures adjacent to the site where HMP is adjacent to the site where HMP is installedinstalled, and , and the locationthe location and and state of underground structuresstate of underground structures must be thoroughly surveyed.must be thoroughly surveyed.





4.2.2 Grout



3.4.3 Boring




4.5 Safety control




3.6 Grout injection











3.4 Boring

2.1 Basic items




CHAPTER 1 GENERAL

1.1 Scope


Major machinery and equipmentMajor machinery and equipment

Sample of Standard Execution Machinety anSample of Standard Execution Machinety and Equipmentd Equipment

Workcategory

Name Specifications Quantity Remarks

Boringmachine

Motor about110PS

1 unitRotary percussion double-wall pipemethod

Water feedpump

15kW 1 unit Ejection rate 300l/min

Water tank 5, 10m3Necessary

numberFor pure water, for slurry

Sand pump 5.5kWNecessary

numberPipe extractor 1 unit Used as necessaryGrout mixer 11kW 1 unit Vertical or two tank horizontal typeGrout pump 15kW 1 unit Ejection rate 300l/minWater meter 1 unitFlow meter 1 unit Used as necessaryCompressor 1 unit

Liftingcapacity4.9 to 25t

Engine drivengenerator

Approx. 45,100kVA

1 unit Used as necessary

1 unit

Boring

Injection

CommonCrane

Contents 3 :Contents 3 : EXECUTION METHOD EXECUTION METHODHMP Exection ProcessHMP Exection Process

Installing a boring machine Mixing grout

Casing boring Initial injection

Washing borehole interior Pulling out HMP steel pipesPressure injection

Withdrawing inner rod

Reinserting HMP steel pipesInserting injection hose

Installing core bars Treatment of pile head

Bor

ing

Inje

ctio

n

The installing angle is set using a The installing angle is set using a slant rule.slant rule.


Boring using 1.5m short HMP steel Boring using 1.5m short HMP steel pipes (as standard) as a casing.pipes (as standard) as a casing.







Bor

ing

Inje

ctio

n

Boring MethodBoring MethodSelection of Boring Method Accoding to GroSelection of Boring Method Accoding to Gro

und Categoryund Category

Sandy orcohesive

soilGravel

Soilcontaining

stonesSoft rock

Mediumhard rock

Hard rock

Rotary percussion double-wallpipe method ◎ ◎ ◎ ○ ○ ○

Down-the-hole hammerdouble-wall pipe method ○ ○ ○ ◎ ◎ ◎

Boring method

Ground categorySoil Rock

Ring bit Drill pipe

Coupling Drill pipe

Water swivel Drive adapter Shank rod (hammer-sub)

エキステンションロッド

エキステンションロッドインナーロッド

インナービット

リングビット

インナービット

リングビット

カップリング

カップリング

エキステンションロッド

インナーロッド

ＨＭＰ鋼管

カップリング

カップリング

ＨＭＰ鋼管

クリーニングアダプター

ウォータースイーベル

クリーニングアダプター

スイーベル

イシュー

シャンクロッド

シャンクロッドＨＭＰ鋼管ＨＭＰ鋼管

Inner bit Inner rod

Extension rod

Ring bit HMP steel pipe Coupling HMP steel pipe

Inner bit Inner rod Coupling Extension rod

Ring bit HMP steel pipe Coupling HMP steel pipe Cleaning adapter

Swivel

Issue Shank rod

Coupling

Extension rod

Extension rod

Cleaning

adapter

Water

swivel

Shank rod

down-the-hole hammerdown-the-hole hammer Rotary percussionRotary percussion


The inside of the borehole is washed The inside of the borehole is washed with pure water or air.with pure water or air.







Bor

ing

Inje

ctio

n

Water or AirWater or Air

BoringBoring

Boring shall be performed byBoring shall be performed by an all-casing an all-casing methodmethod to protect a borehole wall. At this time to protect a borehole wall. At this time HMP steel pipes shall be used asHMP steel pipes shall be used as the casingthe casing. If . If the boring is completed, the inside of the the boring is completed, the inside of the borehole shall beborehole shall be carefully washed to remove carefully washed to remove slimeslime..


The injection hose and core bars are The injection hose and core bars are inserted into the borehole together. inserted into the borehole together.







Bor

ing

Inje

ctio

n


The injection hose and core bars are inserThe injection hose and core bars are inserted into the borehole togethor.ted into the borehole togethor.







Bor

ing

Inje

ctio

n








Bor

ing

Inje

ctio

n

Grout injectionGrout injection

The grout mixtureThe grout mixture must must be set so that it satisfies be set so that it satisfies the design strength of the design strength of 30N/mm30N/mm22 or more or more, and the , and the stipulated workability stipulated workability during pumping and during pumping and injection.injection.

Grout MixtureGrout Mixture

Water Cement Ratio Air content

W/C (%)(%) Water Note 1) Cement

W C50 1 605 1210 Approximately 1.5C%

Unit weight (kg/m3)

Chemical admixtures Note 2)

Sample Grout MixtureSample Grout Mixture








Bor

ing

Inje

ctio

n

groutgrout


Pressure injection is perfomed to the stipuPressure injection is perfomed to the stipulated depth each time HMP steel pipes are wlated depth each time HMP steel pipes are without.ithout.







Bor

ing

Inje

ctio

n


HMP steel pipes are reinserted to the stipulated depth.







Bor

ing

Inje

ctio

n


Treatment of pile head.







Bor

ing

Inje

ctio

n

Treatment of the pile headTreatment of the pile headPile head steel pipes Pile head steel pipes

and a footing are and a footing are connected by connected by a a bearing plate bearing plate methodmethod or or shear ring shear ring methodmethod..

HMP steel pipesHMP steel pipesCore barsCore bars

Bearing plateBearing plate

Reinforcing barsReinforcing bars

HMP steel pipesHMP steel pipes

Shear ringShear ringCotter

NutNut

Shrinkage compensating groutShrinkage compensating grout

HMP steel pipesHMP steel pipesCore barsCore bars

Bearing plateBearing plate

Reinforcing barsReinforcing bars

HMP steel pipesHMP steel pipes

Shear ringShear ringCotter

NutNut

Shrinkage compensating groutShrinkage compensating grout





4.2.2 Grout



3.4.3 Boring




4.5 Safety control




3.6 Grout injection











3.4 Boring

2.1 Basic items




CHAPTER 1 GENERAL

1.1 Scope


CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENTPROCESS : BoringPROCESS : Boring

Management item Managed content Management method Standard valueMeasurement

frequencyEccentricity D/4D: Diameter of

steel pipeBoring angle Boring angle Slant rule ±1° All

Slime sampling,absence of artesian

confirmation of bearinglayer 1 time/1 pile

Design boringor more

Cleanliness of returnwater

Quantity of residualslime

Visually All

Presence/absence of

State of boring Visually

Boring lengthMeasuring rod,measuring tape

All

Obstructions All

Boring location Scale All

Bearing layerdepth, design

value

All

Boring location

Boring depth

Eccentricity : D/4Eccentricity : D/4

DD

CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENTPROCESS : BoringPROCESS : Boring


frequencyEccentricity D/4D: Diameter of

steel pipeBoring angle Boring angle Slant rule ±1° All

Slime sampling,absence of artesian

confirmation of bearinglayer 1 time/1 pile

Design boringor more

Cleanliness of returnwater

Quantity of residualslime

Visually All

Presence/absence of

State of boring Visually

Boring lengthMeasuring rod,measuring tape

All

Obstructions All

Boring location Scale All

Bearing layerdepth, design

value

All

Boring location

Boring depth

±± １１ °°

CHAPTER 4 :CHAPTER 4 : EXECUTION MANAGEMENTEXECUTION MANAGEMENT

PROCESS : Grout injectionPROCESS : Grout injectionManagement item Managed content Management method Standard value

Measurementfrequency

State of Quantity of injection Flow meter Allgrout injection Pressure Pressure gauge All

Specific gravity ofoverflowing grout

Specific gravity gauge(mud balance), scales

Mixed specificgravity ±2%

1 time/1 pile

Chloride ion content ofoverflowing grout

Dry chemistry method Max. 0.30kg/m3 1) 1 time/1 pile

Design strengthor more

Bleeding ratio ofoverflowing grout

Polyethylene bag usedfor measuring bleeding

3% (after 3 hours) 1 time/1 pile

1 time/1 pileCompressive strength of

overflowing groutCompressive testing

　　　　 This is established This is established in conformity with in conformity with the the Japan Concrete Japan Concrete Standard SpecificationsStandard Specifications..


PROCESS : Installation of reinfoecing materPROCESS : Installation of reinfoecing materialial

±50mm±50mm


frequency

State of insertionLocation of pile head

(standard height)Level measurement ±50mm All

State of insertionLocation of pile head

(standard height)Level measurement ±50mm All


PROCESS : Pile head treatmentPROCESS : Pile head treatmentManagement item Managed content Management method Standard value

Measurementfrequency

Eccentricity D/4D: Diameter of

steel pipe

Pouring anglePouring angle of pile

headSlant rule ±2.5° All

Scale AllPile location Pile location

Eccentricity : D/4Eccentricity : D/4

±2.5°±2.5°

DD

Confirming the bearing capacity of HMPConfirming the bearing capacity of HMP

In principle, one of the In principle, one of the following shall be following shall be performed to confirm the performed to confirm the bearing capacity of HMPbearing capacity of HMP

(1) A test pile is executed to confirm (1) A test pile is executed to confirm the execution properties and to the execution properties and to perform a vertical loading test. perform a vertical loading test.

(2) The design bearing capacity is (2) The design bearing capacity is confirmed to perform a vertical confirmed to perform a vertical loading test on an actual pile. loading test on an actual pile.

0

10

20

30

40

50

60

70

80

90

100

0 500 1000 1500 2000

1570(kN)

981(kN)

1177(kN)

687(kN)

It is performed by creating It is performed by creating a low level straina low level strain by by lightly striking the pile head with a hand held lightly striking the pile head with a hand held hammer and hammer and measuring the response at that measuring the response at that timetime with an accelerometer. with an accelerometer.

Hand hammerHand hammer

Acceleration senserAcceleration senser

computercomputer

pile

pile

Outline of the Integrity testOutline of the Integrity test

Speed

depth

time

time

Pile

length

（L

）

time

time

speed

depth

Pile length (L)

Principle of the Integrity testPrinciple of the Integrity test

3@1,500=4,500

3,000750750 2,250750

pipelod

Grout

500 7501,500

6,750

25017

8

Case1Case1

Tese caseTese case

1 m3

m

45°

Case2Case2

Tese caseTese case

Case1Case1

-0.008

-0.006

-0.004

-0.002

0

0.002

0.004

0.006

-1 0 1 2 3 4 5 6 7 8

杭長（ｍ）

(m/s

)速

度

杭頭杭頭

鋼管先端鋼管先端

杭先端杭先端

The reflection The reflection from the end of from the end of the steel pipe the steel pipe and the end of and the end of the pile is the pile is clearly clearly observedobserved..

length

spee

d

Pile head

end of the steel pile

End of the grout

resultresult

CaseCase ２２

土中試験

-0.008

-0.006

-0.004

-0.002

0

0.002

0.004

0.006

-1 0 1 2 3 4 5 6 7 8(m/s

)速

度

増幅処理未処理

杭頭杭頭


杭先端杭先端

土中試験

-0.008

-0.006

-0.004

-0.002

0

0.002

0.004

0.006

-1 0 1 2 3 4 5 6 7 8(m/s

)速

度

増幅処理未処理

杭頭杭頭


杭先端杭先端

resultresult

Length(m)

spee

d

Pile head

end of the steel pile

End of the grout

杭頭

グラウト拡大部

杭先端

m

杭頭

グラウト拡大部

杭先端

m

This created a longer anchored portion than originally designed.This created a longer anchored portion than originally designed.

Ground testGround test

1,500

1,500

1,500

4,500

7,500

1,500

支持層

1,500

1,500

1,500

4,500

7,500

1,500

支持層

1,500

1,500

1,500

4,500 7,500

1,500

CONCLUSIONCONCLUSION The effect on the ground can be reduced by proThe effect on the ground can be reduced by pro

cessing the amplitude of the measured waveform, cessing the amplitude of the measured waveform, even for HMPs with their complex structure.even for HMPs with their complex structure.

The reflecting wave form the grout expansion pThe reflecting wave form the grout expansion portion, the end of the steel pipe, and the pile can ortion, the end of the steel pipe, and the pile can definitely be measured to a certent.definitely be measured to a certent.

Applicability for HMP quality controlApplicability for HMP quality control

・・ We believe an effective method would be to compare We believe an effective method would be to compare tthe survey results for all the HMPshe survey results for all the HMPs and to select those pil and to select those piles that can be expected to perform poorly based on a reles that can be expected to perform poorly based on a relative evaluation.ative evaluation.

Thank you for your attention.Thank you for your attention.

ENDEND

outline of the execution manual for seismic retrofitting of existing pile foundations with high...

Documents

execution manual

execution managementprocess

execution yard condition

boring boring

time hmp steel pipes

short hmp steel pipes

pile headpile head steel

injection hose