Unternehmenspräsentation Geosynthetic Reinforced Wall ... · PDF fileUnternehmenspräsentationGeosynthetic Reinforced Wall Design acc. to EBGEO Conclusion 12.11.2015 33 ... DIN 1054

UnternehmenspräsentationGeosynthetic Reinforced Wall Design acc. to EBGEO

UnternehmenspräsentationGeosynthetic Reinforced Wall Design acc. to EBGEO 12.11.2015

Workshop – Reinforced fills with GeosyntheticsMarie-Therese van Keßel, M.Sc.

Engineering Department, Huesker Synthetic GmbH

Geosynthetic Reinforced Wall Design

acc. to EBGEO

2


Outline

12.11.2015 3

Geotechnical Design Guidelines in Germany

EBGEO

Introduction

Safety Analysis

Large Scale Tests and Monitoring

Case Study

Conclusion


Geotechnical Design in Germany

Overview

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Figure 1: German regulation overview (modification Witt)



Partial Safety Factors

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Figure 1: Partial Safety Factors for Effects (DIN 1054), Part I Figure 2: Partial Safety Factors for Effects (DIN 1054), Part II



Partial Safety Factors

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Figure 1: Partial Safety Factors for Geotechnical parameters (DIN 1054)

Figure 2: Partial Safety Factors for Geotechnical parameters for Resistance (DIN 1054)

gM


EBGEO

Introduction

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Recommendations for Design and Analysis of Earth Structures using

Geosynthetic Reinforcements – EBGEO

Embankment on Soft Soil

Reinforced Foundation Pads

Transport Routes

Retaining Structures

Landfill Engineering

Piled Embankments

Geosynthetic Encased Columns

Sinkholes


EBGEO

Design Strength of Reinforcement

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EBGEO, section 3.3.1

Rb,k=RB,k0

A1∙A2∙A3∙A4∙A5, RB,d =

RB,k

gMRb,k Characterstic long term strength

Rb,k,0 Characterstic short term strength

Rb,d Design strength

A1 Reduction factor for creep

A2 Reduction factor for installation damage

A3 Reduction factor for processing

A4 Reduction factor for environmental/chemical impact

A5 Reduction factor for dynamic loads

gM Material Partial Safety Factor


90°

EBGEO

Retaining Structure

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Figure 1: Geosynthetic Reinforced Retaining Structure (GRS)



EBGEO

Retaining Structure

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Demands and Boundary Conditions (Section 7.2.1)

Ground conditions below and behind and below the retaining structure

Location of ground water table

Impact of perched water

Any excavation battering angle or existing slopes

Height and inclination of the reinforced retaining structure

Design and requirements of facing

Planned design working life

Actions on the structure

Allowable deformations

Properties of intended materials


EBGEO

Retaining Structure - Analysis

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Analysis LS EBGEO-section

Ultimate Limit State ULSGeneral Failure/Slope Failure GEO 7.4.4

Bearing Capacity Failure STR 7.4.5

Sliding STR 7.4.6

Position Of Bearing Pressure Resultant EQU 7.4.7

Failure On Slip Planes Penetrating The Retaining Structure GEO 7.4.1

Design Strength Of Reinforcement STR 7.4.3

Pull-Out Resistance Of Reinforcement GEO 7.4.3

Analysis Of Connections STR 7.6

Analysis Of Reinforcement Overlapping/Joining (Reinforcement Junctions) STR 7.6

Serviceability Limit State SLSPosition Of Bearing Pressure Resultant SLS 7.5.2

Deformation Of The Structure SLS 7.5

Settlement In The Contact Zone SLS 7.5


EBGEO

Retaining Structure – Slope Failure (DIN 4084)

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Figure 1: Internal failure lines Figure 2: External / global failure lines Figure 3: Compound faillure lines


EBGEO

Retaining Structure – General Failure / Slope Failure (DIN 4084)

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Figure 1: External Failure Analysis, 7 Slices, (Bishop) Figure 2: External Failure Analysis, 50 Slices, (Bishop) Figure 3: External Failure Analysis, 150 Slices (Bishop)


Lessons Learnt

Retaining Structure – General Failure / Slope Failure (DIN 4084)

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Figure 1: External Failure Analysis, 50 Slices (Bishop) Figure 2: External Failure Analysis, (Vertical Slice)


EBGEO

Retaining Structures - Design Strength and Pull-out of

reinforcement

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Figure 1: Sketch, Distribution of forces, EBGEOFigure 2: Sketch, Failure mode Rupture of

Reinforcement, EBGEO

Figure 3: Sketch, Failure mode Pull-out, EBGEO

RA,k = sv,k ∙ LA ∙ fsg,k ∙ n• RA,k characteristic pull-out resistance relative to 1 m width

• sv,k characteristic normal stress in reinforcement plane

• LA anchorage length behind the failure plane

• fsg,k characteristic mean friction coefficient (2.2.4.11)

• n number of adoptable frictions surfaces


EBGEO

Retaining Structure – Bearing Capacity, Overturning, Sliding

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Figure 1: Sketch (EBGEO), Bearing Capacity Failure (STR),

based on DIN 1054 and DIN 4017

Figure 2: Sketch (EBGEO), Sliding Failure (STR), based on DIN

1054

Figure 3: Sketch (EBGEO), Overturning

Failure (EQU and SLS), based on DIN 1054

Figure 4: Kernel width, DIN 1054 (7.5.1)


EBGEO

Retaining Structures - Analysis of Facing Elements

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SLS

in accordance with DIN 4085

Rb,i or RAi,d ≥ Efacing

Efacing = efacing ∙ lv

efacing = hg∙ Kagh,k ∙ gk∙ H ∙ gG + hq ∙ Kaqh,k ∙ q ∙ gQ

Calibration factor Earth pressure angle

hg hq d

0 < h ≤ 0.4 H 0.4 H < h ≤ H

Non-deformable

facing elements1.0 1.0 1.0

Analogous to

DIN 4085

Partially deformable

facing elements1.0 0.7 1.0 1/3 j’ to 1.0 j’

Deformable

facing elements1.0 0.5 1.0 0.0

Table 1: Calibration factor, EBGEO (7.6)

Figure 1: Earth pressure, EBGEO

RAi,d – design value of the entire pull-out

resistance provided by friction or as

connection force (design value determining

using gB

Rb,i – design value of the long-term tensile

strength of the geosynthetics in the nth

reinforcement layer


EBGEO

Retaining Structures - Deformation of the structure

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Intrinsic settlements vE

0.2% ∙ H ≤ vE ≤ 1.0% ∙ H

Horizontal displacements vhi

Tensile force → axial stiffness → strain

distribution → change in length

Numerical model

Shear deformations vS

30% ∙ vHi,max ≤ vs ≤ 50% ∙ vHi,max

Ground settlements vu

Settlement on top of retaining

structure

90

°

vu – ground settlements

vhi – horizontal

displacement of the

slope front at the level of

reinforcement i

vE – intrinsic settlement of

the fill material

vS – shear deformations

vE + vu + vs



Monitoring Parameter and Devices

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Deformations

Strain

Forces




Large Scale Test LGA, Nürnberg

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Large-scale test LGA, Nürnberg

4.5 m high GRS loaded by max.

600 kPa (3 x usual loads for

bridge super structures and

traffic)

Figure 1:Experimental setup, Large scale GRS, LGA Nürnberg, Germany

Source: Alexiew, D. und Detert, O.: Analytical and Numerical Analyses of a Real Scaled Geogrid Reinforced Bridge Abutment Loading Test, EuroGeo4, (2008).



Large Scale Test LGA, Nürnberg

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Large-scale test LGA, Nürnberg

Max. vertical settlements 18 mm

Max. horizontal deformation 10 mm

Figure 2:Results, horizontal deformation at the GRS faceFigure 1: Results, settlements of concrete beam

Source: Alexiew, D. und Detert, O.: Analytical and Numerical Analyses of a Real Scaled Geogrid Reinforced Bridge Abutment Loading Test, EuroGeo4, (2008).



Railway Line Köln-Mülheim

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Figure 1: Horizontal Displacement (related to initial measurement)

Figure 2: Typical cross section and location of inclinometer



Riga South Bridge – Front Facing Deformation

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Figure 1: Typcial cross section, Riga South bridge



Riga South Bridge – Front Facing Deformation (static)

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0

0.5

1

1.5

2

2.5

0 1 2 3 4 5

horizonta

l dis

pla

cem

ent [m

m]

Wall Height [m]

project

step 1

step 1 const

step 2

step 2 const

step 3

unload step 2

unload step 1 Figure 2: Loading of geosynthetic reinforced wall

Figure 1: Horizontal displacement over wall height



Riga South Bridge – Front Facing Deformation (dynamic)

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Figure 1: Horizontal displacement over wall height

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1 2 3 4 5

horizonta

l dis

pla

cem

ent [m

m]

Wall Height [m]

project

unload step 1

step 4

step 5

step 6Distance from facing

step 4: 5 m

step 5: 3 m

step 6: 1 m

Figure 2: Loading of geosynthetic reinforced wall



Riga South Bridge – Front Facing Deformation (dynamic)

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Figure 1: Riga South Bridge, Google maps


Case Study

A 74 Bridge Abutment, Netherland

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Two ecoducts with a geosynthetic

reinforced bridge abutment

Subsoil

soft clay (first 3 m, replaced with sand)

firm sand

very stiff clay layer (20 m below surface)

Preload to compensate settlements

during construction

Attaching half-gabion facing after

settlement completion

Figure 1: Artist impression for A74 bridge abutment


Case Study


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Figure 1: A 74 Bridge Abutment constuction phase Figure 2: A 74 Bridge Abutment construction phase, construction with formwork


Case Study


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Figure 1: A 74 Bridge Abutment with preload, 100 kPa over 3 m for 10 days (8th April – 18th April 2011) Figure 2: A 74 Bridge Abutment with preload


Case Study


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Typical cross section

20 layers of PVA geogrid

26 markers along 4 verticals

4th April – 24th August 2011

Preload 300 kPa (≈ bridge deck)

April 2011

Final load 510 kPa

July 2011

Figure 1: A 74 Bridge Abutment, Typical cross section

Figure 2: A 74 Bridge Abutment, measurement system


Difference between both curves describe the settlements within fill

Settlements below geosynthetic abutment dominates

Settlements after bridge deck installation doubles initial settlement

Resulting from back fill installed simultaniously with bridge deck

Case Study


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Figure 1: A 74 Bridge Abutment, Vertical Deformation, top of abutment, van

Duijnen et al. (2012)

Figure 2: A 74 Bridge Abutment, Vertical Deformation, bottom of abutment, van

Duijnen et al. (2012)


Case Study


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Figure 1: A 74 Bridge Abutment with bridge deck, upon completion, August 2011 Figure 2: A 74 Bridge Abutment, 2014


Conclusion

12.11.2015 33

Geosynthetic Reinforced Wall Design in Germany

is regulated in EBGEO (2010)

based on Eurocode 7, DIN 1054 (German Annex), DIN 4084, DIN 4017, DIN

4085…

slopes, steep slopes, walls, abutments are designed using the same approach

partial safety factors for effects, resistances and geotechnical parameters are

given in DIN 1054

no distinction between filling soil, back fill, subsoil

Large Scale Test and Monitoring

geosynthetic reinforced walls have been built, tested and monitored

performance very good

Proper design and installation is from a high importance

UnternehmenspräsentationGeosynthetic Reinforced Wall Design acc. to EBGEO 12.11.2015

Thank you very much for your attention!

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Unternehmenspräsentation Geosynthetic Reinforced Wall ... · PDF fileUnternehmenspräsentationGeosynthetic Reinforced Wall Design acc. to EBGEO Conclusion 12.11.2015 33 ... DIN 1054