Nobuyuki MATSUI, Manager (B. Eng.(Civil), MSc(Civil), Welding Engineer(JWES1)

Nippon Steel & Sumitomo Metal

Southeast Asia Pte. Ltd. ,Singapore

Technical solutions by

Hat-type Steel Sheet Piles

for enhancing safety and productivity in construction

Today’s Topics

1. Outline of Hat-type steel sheet piles

2. Design Consideration for sheet pile in Eurocode

3. 4 point bending test for Hat type sheet pile

4. Combined Sheet Pile using HAT type sheet Pile

Types of steel sheet Piles

・Effective width is 900mm

(Maximum in the world as rolled piles)

・Direction of piling are same

・Slender and effective section

■ Characteristic of Hat-type sheet piles

400

900

・Type Ⅲ

・NS-SP-10H

U type

Hat type

Benefit of applying Hat-type sheet Piles

1．Rapid construction - Installed combined pile which has 900mm width sheet pile

2．Reduction of steel weight of walls - Slender section and 100% full sectional performance

3．Utility for any requirements - Assorted section type and high applicability

1．Rapid construction - Installed combined pile which has 900mm width sheet pile

2．Reduction of steel weight of walls - Slender section and 100% full sectional performance

3．Utility for any requirements - Assorted section type and high applicability

HAT type sheet piles can make construction affordable

HAT type sheet piles can make construction affordable

U-type steel sheet pile

U-Type Sheet Pile -Conventional type-

Robust

15

900

368

17

900

370

10.8

900

230

13.2

900

300

Slender/Compact/Affordable

1) Effective width is 900mm, the widest rolled sheet pile in the world. 2) Reduce the number of sheet piles, construction period and cost.

Hat-type steel sheet pile

■ Hat-Type Steel Sheet Pile

HAT-Type

U-Type

45% number of piles reduction

10H 25H

45H 50H

Temporary wall Quay wall

Retaining wall

Application of Hat-type steel sheet piles

River Revetment

900mm

600mm

400mm

Hat Type(Hat900）[10H]

U-wide Type(U600）[Ⅱw]

U Type(U400）[Ⅱ]

Neutral axis of each piles and that of interlocked wall are equivalent

900mm

600mm

400mm

Hat Type(Hat900）[10H]

U-wide Type(U600）[Ⅱw]

U Type(U400）[Ⅱ]

Neutral axis of each piles and that of interlocked wall are equivalent

U-type wall transmits longitudinal shear force to adjacent piles at interlocks. If the shear

force is not transmitted properly due to slippage at interlocks, moment capacity of the wall

should be reduced and the wall deflection will increase.

Hat-type wall is not necessary to be considered this effects because the interlocks are

located on the outermost part of the wall where the shear force is negligible

900mm

600mm

400mm

Hat Type(Hat900）[10H]

U-wide Type(U600）[Ⅱw]

U Type(U400）[Ⅱ]

Neutral axis of each piles and that of interlocked wall are equivalent

900mm

600mm

400mm

Hat Type(Hat900）[10H]

U-wide Type(U600）[Ⅱw]

U Type(U400）[Ⅱ]

Neutral axis of each piles and that of interlocked wall are equivalent

Interlock integrity of sheet pile

y1

y0

ey

M

T

T

鋼矢板1枚での

中立軸

実際の中立軸

STATE A

Neutral axis

of practical wall Neutral axis

of pile

STATE B PRACTICAL STATE

Slip at Joint

Types of steel sheet piles in Eurocode

■ Eurocode 3 - Design of Steel Structures- Part 5: Piling

10

where :

Wel is the elastic section modulus determined for a continuous wall;

Wpl is the plastic section modulus determined for a continuous wall;

γM0 Partial safety factor (=1.0)

βB is a reduction factor that account for a possible lack of shear force

transmission in the interlocks.

βB = 1.0 for Z-piles and triple U-piles

βB ≤ 1.0 for single and double U-piles

Class 1 or 2 Class 3

c,Rd pl y M0BM W f 0c,Rd el y MBM W f

Design moment resistance in the Eurocode

Reduction factor for U-type sheet piles

11

where:

I is the second moment of area of the continuous wall

E is Young’s modulus

βD is to account for the possible reduction due to insufficient shear force

transmission in the interlock.

βD = 1.0 for Z-piles and triple U-piles

βD ≤ 1.0 for single and double U-piles

The numerical value for βB and βD are given in the National Annex.

eff DEI EI

Reduction factor for U-type sheet piles

Design effective flexural stiffness in the Eurocode

12

Type of U-pile unit

Number of structural

support levels

Reduction factor βB and βD

Highly unfavorable conditions

Unfavorable conditions

Favorable conditions

βB βD βB βD βB βD

Singles or uncrimped doubles

0 0.40 0.30 0.50 0.35 0.60 0.40

1 0.55 0.35 0.60 0.40 0.70 0.45

> 1 0.65 0.45 0.70 0.50 0.80 0.55

Crimped or welded doubles

0 0.70 0.60 0.75 0.65 0.80 0.70

1 0.80 0.70 0.85 0.75 0.95 0.80

> 1 0.90 0.80 0.95 0.85 1.00 0.90

Reduction factor for U-type sheet piles

Reduction factor for U-type sheet piles in the National Annex

13

Interlocks not treated with sealants or lubricants

• βB may be increased by 0.05 (to a maximum value of 1.0)

• βD may be increased by 0.05 (to a maximum value of 1.0)

Welding near the wall top

• βB may be increased by 0.1, 0.15 or 0.2 respectively for highly

unfavorable, unfavorable and favorable conditions ( to a maximum

value of 1.0)

• βD may be increased by 0.15, 0.2 or 0.25 respectively for highly

unfavorable, unfavorable and favorable conditions ( to a maximum

value of 1.0)

Reduction factor for U-type sheet piles

Countermeasures for enhancing the reduction factor

0

10000

20000

30000

40000

50000

60000

70000

80 120 160 200 240

Unit weight per 1m wall width (kg/m2)

10H

25H

ⅡⅢ

Ⅳ

ⅤL

Mo

me

nt

of

Iners

ia p

er

1m

wa

ll w

idth

(m3

/m)

45H

50H

Influence of interlock integrity

▽36％

▽34％

▽23％ Joint efficiency

=0.6

Hat type sheet pile can be reduce the steel weight

Recommendation to Hat-type sheet piles

Similar with Z-type piles, for a wall using Hat-type steel piles, the

reduction factors are NOT required (βB = 1.0 , βD

= 1.0 ) because

interlocks are located at the most outer edge of the wall, which

means that the shear force does not occur in the interlocks.

• Place : Nanyang Technological University

(Supervised by Dr. Chiew Sing-Ping)

• Machinery : 100t Compression machine

• Specimen : Hat-type sheet pile (10H×2 piles)

(Manufactured in Japan)

• Measurement: Load, Displacement, Strain

Structural Test Plan （NTU in Singapore)

P/2

2300 1000 1000 2300

P/2

Type NS-SP-10H

Grade SYW295

Pile Length(m) 8

Moment of Inertia

(cm4/2piles)18,860

Section Modulus

(cm3/2piles)1,624

Material Yield Strength

(MPa)295

• Dimension

Behavior of Hat-type (NTU in Singapore)

• The flexural behavior exceeding yield strength could be verified.

• There is no evidence of any slippage at the interlock between

the 2 piles.

■ After the loading on the sheet piles

Interlocking position after

the loading

Bending Test Results (NTU in Singapore)

• Flexural rigidity in elastic range was equivalent to the theoretical one

• The section kept elastic by its calculated plastic load

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250

Lo

ad

(kN

)

Vertical displacement at center(mm)

Theoritical Elastic line

Tested curve

NTU FEM(ABAQUS)

Pmax=694kN

Calculated Plastic Load

Calculated Yield Load

■ Load-Deflection behavior

0

50

100

150

200

250

-4000 -3000 -2000 -1000 0 1000 2000 3000 4000

strain at Center(μ)

201kN

402kN

601kN

Strain was distributed from above to bottom and the value become 0 at neutral line so the Navier hypothesis is applicable

■ Strain distribution along cross section at center

Neutral Line

Arrangement of strain gages

Bending Test Results (NTU in Singapore)

Additional concerns of sheet piles

Hat type sheet pile can be evaluated as Class2 section in Eurocode

• In case of Hat-type sheet pile

(for SYW295)

Sectional performance of Hat-type

1. It was verified that strength exceeded its design value

• Flexural rigidity in elastic range was equivalent to the theoretical one

• After the yielding, plastic behavior can be obtained without the decline of

strength by buckling

2. Hat type sheet pile can be expected 100% of its sectional

performance.

• There is no evidence of any slippage at the interlock between the 2 piles.

3. Based on above results, Hat-type sheet pile should be

considered its full sectional performance and evaluated as Class

2 in Eurocode

Other Hat-type sheet piles

Improvement Drainage in Singapore(Roselane)

■ Solutions for narrow working space

NS-SP-J

• NS-SP-J can minimize working space.

It can be unnecessary to relocate existing

structure such as residences.

• Interlock integrity can be treated as 100%

because the interlocks locates on outermost

H-beam

Steel sheet piles

Fillet welding

(partial)

(Hat-type)

New Application of Steel Pipe Pile(HAT+H)

- High stiffness sheet pile-

0

200

400

600

800

1000

1200

0.000 0.005 0.010 0.015

Be

nd

ing

Mo

me

nt

(kN

m)

Curvature (1/m)

Experimental Value

Calculated Value

Theoretical Yield Moment

High Stiffness & Effective Section

U-type

Hat + H

■ Moment of Inertia

Flexural Test

Neutral Axis

Neutral Axis of wall

Neutral Axis of pile

1) Composite Section Flexural Test Result

2) 100% Joint Efficiency

Numerous sectional properties

【1 Sheet pile & 1 H beam combined type】

■ Optimization of design 【2 Sheet pile & 1 H beam combined type】

Easy Fabrication in Construction Site

Fabrication manual

In Indonesia (2013)

In Singapore (2014)

In Indonesia (2013)

• 40-60% of Pile length expected to

be welded by Fillet Welding

• The Procedure can be referred to

Fabrication Manual by NSSMC

Type U-Type + Soldier Pile Hat+H

Outline

Spec. H beam section:UB610×229×243

U type steel sheet pile FSP-Ⅳ

HAT + H

10H + HY700×250×12×19

Unit weight 342kg/m(1.0) 256kg/m(0.7 : Z equivalent)

173kg/m(0.5 : I equivalent)

Installation 2 Piles InstalIation

Installed U-type and soldier pile

separately

1 Pile InstalIation Installed HAT and H

at the same time

Comparison with conventional walls

-Piling test-

Development for HAT+H in Singapore

-Publish technical papers-

Thank you very much

for your kind attention