New foundations in Japan and

recent pile researches

in Kyoto University

Kyoto University Makoto Kimura

kimura.makoto.8r@kyoto-u.ac.jp

Contents

・ Japanese design ideas of road

bridge foundations

・ New pile foundation in Japan

・ Investigation of mechanical

behavior of pile group

Seismic design for pier and foundation

橋脚

フーチング

杭

軟弱地盤

硬い地盤

路線直角方向から見た図 路線方向から見た図

No foundation

failure

（杭）基礎

earthquake force for design

Horizontal bearing capacity on pier

Horizontal bearing capacity on foundation

＜

Earthquake force for design＜Basic idea

for seismic designearthquake force for design

橋脚の水平耐力

基礎の水平耐力

設計想定地震力

Needs of seismic reinforcement for existing foundations

Stiffness of pier

Reinforcement for existing foundations

Horizontal bearing capacity on foundation

＜

Earthquake force for design＜ Increase

After Kobe earthquake

Reinforcement of pier

Reinforcement of foundation

Pandora’s box

Advancement of numerical methodCombined calculation for upper structure and foundation

0

10

20

30

40

50

0 1 2 3 4 5 6 7 8

ボアホールカメラ調査による杭損傷の累積点数

橋脚基数

Damage to the pile in

the soft ground and

liquefied ground

Needs of seismic reinforcement

for existing foundationsPlastic deformation caused by the earthquake disaster

The Southern Hyogo prefecture EQ in 1995

The 2011 off the Pacific coast of Tohoku EQ

Cracks generated in piles

No

. o

f b

rid

ge p

ier

Cumulative No. of pile damage found

by the bore-hole camera investigation

Based on the reports of restoration for foundation

structures of Kobe line #3 by Hanshin Expressway

e

HV

M

M

H

RM

Ｈ

RM

Ｈ

R

HV

M

M

Ｈ

RM

Ｈ

RM

Ｈ

R

？

Why do we design a footing?

Pile

？ ？

Footing

JACKET FOUNDATION WITH INCLINED PILES

Jacket structure

Pier

Steel pile

Stuff substratum

Soft soil layer

Offshore pile foundations for roads

Not so heavy

Jacket steel pile

foundation

with inclined piles

Jacket leg

Steel pile

Ballast tank

AXIAL LOAD DISTRIBUTION(STATIC)

-6

-4

-2

0

2

4

6

No.1 No.2 No.3 No.4

Ax

ial

forc

e 　(M

N)

TypeA : Analysis (at 6.61s)

TypeA : Test (at 6.30s)

TypeB : Analysis (at 6.59s)

TypeB : Test (at 6.17s)

Inertial force

1 2 3 4

Inertial force

1 2 3 4

Type A

Type B

Inertial force of a superstructure

Com

pre

ssio

n

(+)

Ten

sion

(-)

PILE FOUNDATION AND CAISSON FOUNDATION

(Unit:m)

＜Remarks＞ C.G.：Center of gravity

Pile foundation

Elastic beam Plastic beam

C.G. of superstructure

Rubber bearing

Pier

Superstructure

33

.38

.0

0.9

Elastic beam

5.0

G.L.-39.4

25

Caisson

C.G. of superstructure

18

.8

Rubber bearing

14

.58

.0

2.2

59

.4C.G. of jacket structure

C.G. of tank

Pier

A A0.4

20° 20°

Inclined pile Vertical pile

Superstructure

Substructure

Elastic solid elementAc

Asc

AsDS1

Ds2

Caisson foundation

RESPONSE FOR ACCELERATION AND DISPLACEMENT

-8.0

-4.0

0.0

4.0

8.0

0 2 4 6 8 10 12

Time (sec)

Acc

eler

atio

n (

m/s

2) Pile foundation

Caisson foundation

-2.0

-1.0

0.0

1.0

2.0

0 2 4 6 8 10 12

Time (sec)

Dis

pla

cem

ent

(m) Pile foundation

Caisson foundation

-8.0

-4.0

0.0

4.0

8.0

0 2 4 6 8 10 12

Time (sec)

Acc

eler

atio

n (

m/s

2)

Acceleration Displacement

-0.2

-0.1

0.0

0.1

0.2

0 2 4 6 8 10 12

Time (sec)

Dis

pla

cem

ent

(m)

Upper structure

Foundation

Upper structure

Foundation

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Shaking table test and numerical simulation on seismic performance of a bridge column integrated by multiple steel pipes with directly-connected piles

Koichi Isobe (Hokkaido University) H. Sugiyama, M. Shinohara, H. Kobayashi (Hanshin Expressway)

Y. Sawamura, Y. Mitsuyoshi, M. Kimura (Kyoto University)

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Development of “Integrated column by multiple steel pipes” (2004)

⚫ A bridge column integrated by 4 steel pipes and multiple shear panels interconnecting the pipes has been proposed.

⚫ It is designed based on damage control concept, in which the vertical load is supported by the steel pipes and the lateral load is adjunctively supported by shear links.

⚫ Shear panels are made of low yield stress steel and have hysteretic energy dissipation properties.

⚫ It intends to lead seismic damage into shear panels and enables early recovery by replacing only panels.

Introduction

12

Steel pipe

Shear panel

made of

low yield

steel

Shear link

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Development of “Integrated column by multiple steel pipes” (2004)

⚫ Budget-pleasing prefabricated material (ready-made spiral steel pipes) are used.

⚫ Anchor frame is NOT necessary unlike a conventional steel pier structure.

⚫ Reduce 30% of construction cost

⚫ Reduce construction time

⚫ Rapid transportation open

Introduction

13

NO Anchor frame

Cost analysis

Pile group Integrated column by multiple steel pipes

1.00 1.18 0.82 1.00 0.65

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IntroductionProposal of “Steel pipe pile foundation” for integrated column

⚫ Each pipe of the column is supported by a directly connected steel pile without a footing

⚫ Maybe rational & reasonable foundation structure for “A bridge column integrated column by multiple steel pipes”

⚫ Not impair the ability of the integrated column structure

⚫ Reduce inertia force and sectional force at the connected area between piles and column

⚫ Reduce the cost of footing and the number of piles

⚫ Can employ the pile foundation in narrow construction conditions

ConventionalGP foundationwith Footing

Way-outDirectly connected

without Footing

Energydissipation

Footing

3 x 3piles

2 x 2piles

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Purpose of Study

Shaking table test and Numerical simulation

⚫ To compare the both seismic performance (footing type vs footing-less type) ➢ Axial force acting at pile heads➢ Lateral displacement at a pier top and pile heads➢ Cross sectional force acting in a bridge column and

piles⚫ To confirm the yield order of the member for the

proposed structure⚫ To check the behavior of the proposed structure in

liquefiable sand⚫ To identify the structural issues of the proposed type⚫ To cross-check analytical model by simulating the model

tests

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Outline of Shaking table testShaking table and Large-scale rigid box with tempered glass

⚫ Public Works Research Institute in Tsukuba⚫ Large-scale 3-dimensional shaking table⚫ Table size: 8m x 8m⚫ Box size: 4m (W) x 1m (L) x 2m (H)⚫ See the ground through the tempered glass

4m 2m

1m

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Outline of Shaking table testDetail of the model used in the tests

welded

659.5

474

338

338

338

89.5

1577

.5

34

1765

.5

32

Dp 8

9.1

560

2.5Dp

2.5Dp

3409

Dc

76.3

680

474

338

338

376.5

1579

34

1764

32

Dp 8

9.1

560

2.5Dp

Dc

76.3

680

Member MaterialSteel pipe

Shear panel

Underground

beam

STK400LY225

SS400

223.7

5

223.75

94

76.3

Unit : mm

welded

Shear panel

Underground

beam

223.75 223.75

223.7

5223.7

5

659.5

659.5

Footing

147.45

9177

Underground beam

76.3 94

61106.2

61

147.45Shear panel

Strain gauge

Triaxial Strain

gauge

F-type S-type

2.5Dp

Shear panels

Underground beamFooting type Footing-less

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Outline of Shaking table test

Footing type Footing-less type

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-6

-4

-2

0

2

4

6

-60 -40 -20 0 20 40 60

Res

po

nse

acce

lera

tio

n a

t p

ier

top [

m/s

ec2]

Lateral displacement at pier top [mm]

Case-1-F

Case-1-S

Step 8Step 3

Step 3

Step 1

Pier top

20

Results of Shaking table test Dry sand

Response acceleration vs lateral displacement @ pier top

Lateral disp. @ pier top (mm)

Input wave acc.(1) 0.5 m/s2

(2) 1.0 m/s2

(3) 1.5 m/s2

(4) 2.0 m/s2

(5) 2.5 m/s2

(6) 3.0 m/s2

(7) 3.5 m/s2

(8) 5.0 m/s2

Resp

onse

acc

. @

pie

r to

p (g

al)

⚫ The stiffness of Case-1-F (D-F) is bigger than that of Case-1-S (D-S).

⚫ Case-1-F yields at earlier stage than Case-1-S.⚫ Response acceleration and lateral displacement for Case-1-

F increase rapidly and brittle deformation is observed.

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Shaking direction

Shaking direction

Shaking direction

-3000 -2000 -1000 0 1000 2000 3000-2

-1.5

-1

-0.5

0

0.5

1

1.5

Heig

ht

[m]

Strain (×10-6)

G.L.

Yield strain

-2

-1.5

-1

-0.5

0

0.5

1

1.5

-3000 -2000 -1000 0 1000 2000 3000

Heig

ht

[m]

Strain (×10-6)

Shaking direction

Shaking direction

Shaking direction

G.L.

Yield strain

Results of Shaking table testStrain on the structure at Step 3

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Results of Shaking table testDamage process of the member

22

⚫ The proposed substructure (Case-1-S) have advantages of strain reduction of column by strain descentralization at footing point.

⚫ It has high seismic performance and high toughness if the conditions are right in view of the fact that the main member (columns and piles) holds a large residual strength after yielding of the shear panels.

加振No. (最大入力加速度) 上段 中段 下段 柱 杭 上段 中段 下段 柱 杭

第1加振 (0.5 m/sec2)

第2加振 (1.0 m/sec2)

第3加振 (1.5 m/sec2)

第4加振 (2.0 m/sec2)

第5加振 (2.5 m/sec2)

第6加振 (3.0 m/sec2)

第7加振 (3.5 m/sec2)

第8加振 (5.0 m/sec2)

フーチングを有する杭基礎 (Case-1-F) 杭基礎一体型 (Case-1-S)

せん断パネル 鋼管 せん断パネル地中梁

鋼管

塑性

面外変形

弾性 弾性

塑性

塑性の可能性あり

せん断パネル 柱・杭 (鋼管)

(a)

(b)

(c)

(a)

(b)

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Summary for model tests

⚫ Based on the fact that the main members such as the columns and piles yield after the shear panels (secondary member) yield, the proposed structure has a damage control performance by energy absorption due to plastic deformation of the shear panels.

⚫ In particular, S-type has high seismic performance because the main member (columns and piles) holds a large residual strength even after yielding of the shear panels.

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My new pile foundations

24

25/23

5.2 LNG receiving terminal and LNG tank

45,000 m3

48 m2

5 m

反力体直列3本群杭試験体

9×7群杭試験体

単杭試験体

直列2本群杭試験体

500 t ジャッキ

変位計，ひずみ計設置点

傾斜計設置点

25

.5

支持層φ 0.4

G.L.

14.0

Unit : m

14 m

18

m

柱状

図

N値

0 20 40

Colu-mnar sec-tion

N value

Double-walled metal tank

Group pile foundation

(496 of steel pipe pile)

LNG tank

LNG receiving terminal

⇒demolished after 40 years service

⇒can be used for loading test

LNG tank need enough stability even if earthquake

5.3 Experimental condition

反力体3 × 1 group pile specimen Reaction piles

7 × 9 group

pile specimen

14 m

Strain gauge,Displacement transducer

Inclinometer

Loading

direction1

8 m

5,000 kN jack

496 of steel pipe pile

demolished after

40 years service

LNG tank

48 m Reaction

piles

7×9 group pile

5000 kN jack

040008000

1200016000

240002800032000

20000

0 1 2 3 4 5 6

36000

Lo

ad

(kN

)

Time (Hour)

Capacity of jack

GL

Slab

6000

Steel pipe pile

f 406.4

Thickness 12.7

800

Protective

concrete

Unit

(mm)

800

⇒Prediction FEM analysis

to decide max. load

5.3 Experimental conditions

27/19

0

4000

8000

12000

16000

24000

28000

32000

20000

0 1 2 3 4 5 6

36000

Lo

ad

(kN

)

Time (Hour)

Capacity of jack

Unidirectional multiple-cycle

multiple-step loading (6 cycle)

Max. load is decided to 30,000 kN

⇒ How to decide max. load?

It is very difficult

to calculate the load

to see ultimate behavior of

63 of group pile foundation

3D elasto-plastic FEM analysis

= Simulating group pile effect

elast-plastic approximate solution

⇒ Conducted prediction analysis

to decide max. load

5.4 Prediction analysis condition

28/19

Prediction analysis by 3 dimensional elasto-plastic FEM1

8 m

14 m

Loading

direction

Reaction

piles

5,000 kN jack

7 × 9

group pile

Analysis area

25

m

7 × 9

group pile

14 m

9 m

32

m

54 m

Elevation View

Ｃ Ｌ

Ground

improvement

Circumference

of tank

foundation

Top View

Pile : Hybrid model (Bilinear) Ground : Subloading tij model

Beam (Bilinear)

Solid element1/10 EI of real pile

Practical pile

(steel pile pile)

Beam element

(Biliear model)

1/10 stiffness of

solid element

is arranged around

beam element Hybrid element

40cm

40cm40

cm

90

cm

80

cm

40 cmPrediction analysis Analysis of after test

Hy

bri

d e

lem

ent

Hy

bri

d e

lem

ent

Bea

m

Slab (elastic) Slab (elastic)

Ground

surface

Ground

surface

5.4 Prediction analysis model

29/23

ＣＬ

The front of

anchor piles

14 m2 m = 5d (d : pile diameter)

2 m

9 × 7 group pileRemaining pile aroundＸ

Ｙ

Loading direction

Pile group effect depend on L/d

Only beam element model overestimate pile spacing L

and pile group effect is misesteemed

5.5 Results ~Load-displacement~

30/19

0

4000

8000

12000

16000

20000

24000

28000

32000

36000

40000

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280

Literal displacement at loading point（mm）

Pre

diction

analys

is

Ap

plie

d lo

ad（

kN）

0

4000

8000

12000

16000

20000

24000

28000

32000

36000

40000

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280

Literal displacement at loading point（mm）

Pre

diction

analys

is

Test

Ap

plie

d lo

ad（

kN）

0

4000

8000

12000

16000

20000

24000

28000

32000

36000

40000

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280

Literal displacement at loading point（mm）

Pre

diction

analys

is

Analysis after th

e test

Test

Ap

plie

d lo

ad（

kN）

Even high load, remain stiffness ⇒not reasonable

Actually, ultimate load was lower (25400 kN)

Maximum load

Simulate accurately at initial phase but not after yield

Practical pile

(steel pile pile)

Beam element

(Biliear model)

1/10 stiffness of

solid element

is arranged around

beam element Hybrid element

40cm

40cm40

cm

90 c

m80 c

m

40 cmPrediction analysis Analysis of after test

Hybri

d e

lem

ent

Hybri

d e

lem

ent

Bea

m

Slab (elastic) Slab (elastic)

Ground

surface

Ground

surface

Practical pile

(steel pile pile)

Beam element

(Biliear model)

1/10 stiffness of

solid element

is arranged around

beam element Hybrid element

40cm

40cm40

cm

90 c

m80 c

m

40 cmPrediction analysis Analysis of after test

Hybri

d e

lem

ent

Hybri

d e

lem

ent

Bea

m

Slab (elastic) Slab (elastic)

Ground

surface

Ground

surface

Solid element of pile head share

high load at large deformation

Plastic

behavior

simulated

Yield load in design

(Chang’s formula)

Ultimate load

⇒ductile deformation over yield load in design

5.5 Results ~deformation of group pile~

The front pile

Loading direction

The second pile

Loading direction

The front pile

2.2° 1.8° 1.7° 1.6°

Front Back

-1.4 m

-2.4 m

-2.9 m-3.4 m -3.6 m -3.8 m -3.9 m

Position of the maximum bending moment from FEM result

3.0°4.1° 3.0°1.5°1.5°1.5°

25,400 kN applied

Loading direction

0.25° 0.26°0.27°0.30° 0.24°0.25°

-2.1 m-2.5 m

-2.8 m-3.2 m-3.2 m-3.1 m-3.0 m

Front Back

Incline

FEM

Test0.24°

0.19°0.22° 0.16°

8,000 kN applied

Loading direction

Position of the maximum bending moment from FEM result

5.5 Results ~Load share of each pile~

32/19

Lo

ad

sh

are

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

① ② ③ ④ ⑤ ⑥ ⑦

Front Back

FEM

Test

16,000 kN

FEM

Test

12,000 kN

FEM

Test

8,000 kN

FEM

Test

4,000 kN

Middle or back pile

share small load

According to

increase of load

load share decrease

Large group pile

effect generate

in spite of L/d = 5

⇒ over 0.9 load share

3×1 group pile L/d = 5

Specific to

large scale group pile