Seismic Design of Bridge Abutments

Thursday, September 28, 2017 2:00-4:00PM ET

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Purpose Discuss the latest research about theories on computing the ultimate passive force for abutment deflection. Learning Objectives

At the end of this webinar, you will be able to: • Understand the differences between available methods for computing

ultimate passive force and correctly compute ultimate passive force for four different materials, including: dense backfills, loose backfills, flowable fills/cellular concrete, and geofoam inclusions

• Compute and adjust passive force for several characteristics, including: skew angle of the abutment, and cyclic loading

• Understand how to select soil parameters for lateral pile analysis of abutment piles

• Use p-multipliers to reduce lateral pile resistance due to group interaction and piles near MSE walls

Seismic Design of Bridge Abutments

Kyle Rollins Civil & Environmental Engineering Brigham Young University

Ralph Rollins, performed geotechnical investigations for over 5000 structures

I took Soil Mechanics class from my Father

Rachel Rollins was Civil Engineering student

Rachel took Soil Mechanics class from her Father

Granddaughter, Ella, shows early interest in soil behavior…

Seismic Design of Bridge Abutments

Kyle Rollins Civil & Environmental Engineering Brigham Young University

Lateral Resistance of Bridge Abutments

Passive force-displacement against abutment

Lateral resistance of piles near MSE wall faces

L

Passive Force on Bridge Abutments

Passive force contributes to resistance Using smaller passive force (lower Kp) may be conservative

Passive Force on Bridge Abutments

Passive force contributes to load Using smaller passive force (lower Kp) is

unconservative

Liquefaction

caption Buckled Railroad Bridge Caused by Lateral Spread During the 1964 Alaska Earthquake

Summary of Passive Force Methods Rankine Coloumb Log Spiral Caltrans

Rankine Method

Advantages • Simplicity • Conservative

Limitations • Planar Shear Surface • Neglects wall friction (δ)

Planar Shear Surface

Pult

Pult= 0.5 γH2 Kp

Only 30% to 50% of correct value

45-ϕ/2

Kp = tan2(45+ϕ/2)

Coulomb Method

Advantages • Accounts for wall

friction (δ) • Complex Geometries

Limitations • Planar Shear Surface • Yields Very High Pult

for δ > 0.4φ

Planar Shear Surface

Pult δ

Pult= 0.5 γH2 Kp

Over 100% higher than correct value

Kp =

cos2ϕ

cosδ 1- sin(ϕ+δ)sin ϕ 2 cosδ

Nature is often non-linear!

Nature likes log spirals!

Log Spiral Method

Advantages • Accounts for wall

friction and shear shape

Limitations • More Complicated • Graphical or

numerical solution

Rankine zone Pult

δ Pult = 0.5 γH2 Kp

Prandl zone

Log spiral Surface

Log Spiral Passive Force

ϕ = Soil friction angle δ = wall friction angle β=backfill slope angle H= height of back wall Kp=passive pressure coefficient Kp can come from chart, Excel spreadsheet PYCAP

Pp = 0.5γH2 Kp

Wall Friction Angle, δ

Noted in AASHTO LRFD (2010)

Duncan and Mokwa (2001)

Caltrans Method

Advantages • Easy to apply

Limitations • Assumes uniform

pressure distribution • Neglects variable soil

strength parameters

)(5.5

5 kipshksfAP eult ××=5.5 ft

5 ksf

Based on field test with silty clay

Bi-Linear Passive Force-Deflection Curve (Caltrans, 2010)

Pult and kabut based on load tests at BYU, UC-Davis and UCLA

Ultimate resistance, Pult = (5.0 ksf)(H/5.5 ft)Awall

Initial resistance, kabut = (50 kip/in)*(H/5.5 ft)*w

Forc

e

Pult kabut

Deflection

AASHTO Design Method

19

• Bi-linear relationship • Failure occurs at 0.01-0.05H

• Peak passive force obtained using log spiral method Pa

ssiv

e Fo

rce

0.01H-0.05H

PP

Hyperbolic Load-Deflection Curve (Duncan and Mokwa, 2001 Shamsabadi et al 2006)

Pult based on log-spiral method

P-y curve based on: • Soil Type • Soil density/stiffness • Cap geometry

“One good test is worth a thousand expert opinions.” Werner Von Braun

Designer of Saturn V Moon Rocket

Healthy Skepticism about Tests A theory is something nobody believes,

except the person who proposed it. An experiment (test) is something

everybody believes,

--Albert Einstein

performed it except the person who

3.67 Ft

Pile Caps/Abutments

12 -Steel Pipe Piles (12.75” OD)

Field Test Methodology 0 2 4 6 8

0

1,000

2,000

3,000

4,000

5,000

0

200

400

600

800

1,000

1,200

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50

Pile Cap Deflection [cm]

Long

itudi

nal F

orce

[kN

]

Long

itudi

nal F

orce

[kip

s]

Pile Cap Deflection [in]

Total Load

Baseline Resistance

Lateral Backfill Resistance

Development of Passive Resistance

0 10 20 30 40 50 60Horizontal deflection at load point (mm)

0

500

1000

1500

Pas

sive

for

ce (

kN)

Clean Sand

0 10 20 30 40 50 60Horizontal deflection at load point (mm)

0

500

1000

1500

Pas

sive

for

ce (

kN)

Fine Gravel

0 10 20 30 40 50 60Horizontal deflection at load point (mm)

0

500

1000

1500

2000

2500

Pas

sive

for

ce (

kN)

Coarse Gravel

0 10 20 30 40 50 60Horizontal deflection at load point (mm)

0

500

1000

1500

2000

2500

Pas

sive

for

ce (

kN)

Silty Sand

Clean Sand

Coarse Gravel

Fine Gravel

Silty Sand

∆/Hmax = 0.034 ∆/Hmax = 0.030

∆/Hmax = 0.035

∆/Hmax = 0.052 “Backbone” Curve

Failure Surface Geometry

Failure Surface Geometry

0 1 2 3 4 5 6-0.30

0.20

0.70

1.20

1.70

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.00 5 10 15 20

Distance from Cap Face on Line Parallel to Direction of Push [m]

Elev

atio

n B

elow

Top

of C

ap [m

]

Elev

atio

n B

elow

Top

of C

ap [f

t]

Distance from Cap Face on Line Parallel to Direction of Push [ft]

Upper Shear Plane

Lower Shear Plane

Heave

α

Comparison of Failure Geometries Rankine Failure Geometry

Log-Spiral Failure Geometry

Ep

Surface of Sliding Comparisons

Silty Sand Fine Gravel Clean Sand Coarse Gravel0

1

2

3

4

5D

ista

nce

in fr

ont o

f pile

cap

(m

)Log spiral theoryEstimated from field data

φ = 27°δ = 20°

c = 27.3 kPa

φ = 34°δ = 26°

c = 3.8 kPa

φ = 39°δ = 30°

c = 0 kPa

φ = 40°δ = 30°

c = 7.2 kPa

1

Measured and Predicted Peak Passive Force

Clean Sand Fine Gravel Coarse Gravel Silty SandMeasured 1090 774 1997 1428Caltrans 914 914 914 914

1577 1149 3464 1575(1577) (824) (2224) (351)

Log spiral numerical solution

922 817 1688 1210

357 405 719 804(357) (300) (474) (194)

Rankine

Numbers in (parenthesis) neglect cohesion component

MethodTotal passive force (kN)

Coulomb

Log Spiral Passive Force-Example

Sandy Gravel γ=135 pcf ϕ = 40º δ = 0.70ϕ = 0.7(40º)=28º H= 6 ft

Pp = 0.5γH2 Kp

Pp = 0.5(135)(6)2 (13.3)=32.3 k/ft PpH = Pp cosδ =32.3 cos(28º)

PpH = 28.5 k/ft

Kp = 13.3

13.3

3D Geometry Effects

Plan View

Shear Zone

Shear zones extend beyond the edge of pile cap/abutment

Increases the effective width of the abutment

B Be

Pile Cap

Load

Equations for 3D Shear Effect Pp = Ep B R3D (Duncan and Mokwa, 2001) where Ep is passive force/width, B is width

Ro = Kp – Ka

Equations for 3D Shear Effect Pp = Ep B R3D (Duncan and Mokwa, 2001) where Ep is passive force/width, B is width

Ro = Kp – Ka

Influence of Relative Compaction

0

50

100

150

200

250

300

350

400

0 0.5 1 1.5 2 2.5 3Deflection (inches)

Pass

ive

Forc

e (k

ips)

Dense Silty Sand(98%)Loose Silty Sand(88%) Dr = 90%

Dr = 40-50%

Failure Planes & Heave Profiles

CLEAN SAND Densely Compacted Loosely Compacted

Shape of failure surfaces appear to reflect mobilization of wall

friction Densely compacted backfill has log-spiral failure surface Loosely compacted backfill has planar (i.e., Rankine) failure

surface

0

2

4

6

8

10

12

14

0 5 10 15 20 25 30

Distance (ft)

Dis

tanc

e (f

t)

Log Spiral

Wall

Ground Surface

Median Heave Profile

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

0 5 10 15 20 25 30

Distance (ft)

Dis

tanc

e (f

t)

Log Spiral

Wall

Ground SurfaceMedian Heave Profile

Vertical Displacements magnified by 10 Vertical Displacements magnified by 10

Dr = 90% Dr = 40-50%

Summary Passive Pressure for non-skewed abutments (Maroney (1995),

Duncan and Mokwa (2001), Rollins and Sparks (2002), Rollins and Cole (2006), Lemnitzer et al (2009) Passive force best estimated using log-spiral method Peak passive force mobilized at displacement of 0.03H to 0.05H Hyperbolic curve best represents passive force-displacement curve

PP

Skewed Bridge Abutment Overview ≈ 40% of 600,000 bridges in US are skewed Current design codes do not consider any

effect of skew on passive force Observations of poor performance of skewed

bridges

Shamsabadi et al. 2006

Earthquake Damage to Skewed Bridges (Paine, Chile)

Top Bridge

Bottom Bridge

Top Bridge

Bridge decks have rotated and bridge was demolished

Bottom Bridge

Bridge deck was offset and was eventually demolished

Top Bridge

Bridge remained in service after the earthquake

Damage rate for skewed bridges was twice that of non-skewed bridges (Toro et al 2013)

Interaction of Forces on Bridge Abutment

Deck Length, L

Skew Angle, θ

PL

Numerical Analysis of Skewed Abutments

(5th NSC, Shamsabadi et al., 2006)

23 m (75 ft) wide abutment with 2.4 m (8 ft) high backwall

Results of Numerical Analysis

(5th NSC, Shamsabadi et al., 2006)

Testing Program Variations in Wingwall Geometry

Variations in Backfill Materials • Sand • Gravel • Geosynthetically Reinforced Soil (GRS)

Transverse Wingwalls Parallel Wingwalls MSE Wingwalls

Initial Laboratory Testing

Test Layout

No Skew

Plan view:

Elevation view:

1.22 m (4 ft)

0.6 m (2 ft)

Test Procedure

Plan view:

Elevation view:

Test “Abutment”

15°

Test “Abutment”

30°

Test “Abutment”

45°

Displacement: 60 mm 2.5” (0.10H) Load measurements: • Longitudinal • Vertical • Transverse

Backfill Soil Properties Gradation and Strength

Property Value Classification SP or A-1-b

Cu 3.7

Cc 0.7

Rc 98%

γ 17.8 kN/m3

ϕ 46º δ 33.2º

Passive Force-Displacement Curves

Reduction Factor for Skew Effects

Rskew= PP(skew)/Pp (No-skew) where Rskew is a function of skew angle, and wall width is equal to non-skewed (projected) width.

Rskew= 8x10-5θ – 0.018 θ + 1.0

(ASCE, J. of Bridge Engrg., Rollins and Jessee 2013)

Normalized Passive Force vs Skew, θ

(ASCE, J. of Bridge Engrg., Rollins and Jessee 2013)

Large Scale Field Testing

Field Test Setup - Plan View

12.75 in Dia. Steel Pipe Piles

11 ft wide x 5.5 ft high Pile Cap

24 ft

22 ft

Transverse Wingwalls 2 x 4 ft Reinforced Concrete blocks

4 ft Dia. Bored Pile Sheet Pile Wall Section AZ-18

2 – 2500 kN Actuators

Field Test Setup Elevation View

11 ft wide x 5.5 ft high x 15 ft long Pile Cap

1.8m 6.4m

4 ft Dia. Bored Pile Sheet Pile Wall Section AZ-18

2 – 600 kip Actuators 12.75 in Dia. Steel Pipe Piles

Sand backfill properties Poorly graded sand (SP/A-1-b) 96% relative compaction ϕ = 41° c = 5 kPa (100 lbs/ft2) γmax = 17.5 kN/m3 (111.5 lbs/ft3)

No Skew - 0° Test Setup

Hydraulic Actuators Simulated

Abutment Concrete Wingwall

Sand Backfill

15° Skew Test Setup

30° Skew Test Setup

45° Skew Test Setup

Test completed at 3.21 in (81.6 mm) of displacement

Test completed at 3.43 in (87.2 mm) of displacement

Heave Geometry at Test Completion 0º Skew 45º Skew

Surface Failure Geometry (30° Skew)

64

Passive Force vs. Displacement 0 2 4 6 8 10

0

500

1,000

1,500

2,000

2,500

0

100

200

300

400

500

600

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Pile Cap Deflection [cm]

Pass

ive

Forc

e [k

N]

Pass

ive

Forc

e [k

ips]

Pile Cap Deflection [in]

0° Skew15° Skew30° Skew45° Skew

0.02

H

0.03

H

0.04

H

0.05

H

Passive Force Reduction Factor vs. Skew

Rskew = 8x10-05θ2 - 0.018θ + 1 R² = 0.98

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 15 30 45 60 75 90

Red

uctio

n Fa

ctor

, Rsk

ew

Skew Angle, θ [degrees]

Lab TestsNumerical AnalysisField Tests (This Study)Proposed Reduction Line

Shear force vs. transverse displacement

020406080

100120140160180200

-0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0

Appl

ied

Shea

r For

ce [k

ip]

Transverse Displacement [in]

30° skew15° skew

45º skew

6.25 5.0 2.5 1.25 3.75 7.5 Transverse Displacement [mm]

Abutment with MSE Wingwalls

Test Setup for MSE Wingwall Tests

15° Skew 30°

Skew

Welded Wire Grid Reinforcement (SSL)

No Skew - 0° Test Setup 12 ft x 5 ft wall panels

15º Skew Test with MSE Wingwalls

Field Test with 30º Skew & MSE Walls

0.0

0.5

1.0

1.5

2.0

2.5

3.00.0 5.0 10.0 15.0 20.0 25.0

MSE

Win

gwal

l D

ispl

acem

ent (

in)

Distance From Pile Cap (ft)

0.24 0.831.72 2.733.18

0.0

0.5

1.0

1.5

2.0

2.5

3.00.0 5.0 10.0 15.0 20.0 25.0

MSE

Win

gwal

l D

ispl

acem

ent (

in)

Distance From Pile Cap (ft)

0.24 0.831.72 2.733.18

0º S

kew

3.35 m

1 to 1.2 in. Displacement

1 to 1.2 in. Displacement

45º S

kew

0.25 in. Displacement

1.5-1.8 in. Displacement

Passive Force-Displacement curves

0.01

H

0.02

H

0.03

H

0.04

H

0.05

H

0.0 2.0 4.0 6.0 8.0 10.0

0

500

1,000

1,500

2,000

2,500

3,000

0

100

200

300

400

500

600

700

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Pile Cap Displacement, Δ [cm]

Pass

ive

Forc

e [k

N]

Pass

ive

Forc

e [k

ips]

Backwall Displacement, Δ [in]

0 Degree Skew30 Degree Skew15 Degree Skew45 Degree Skew

Passive Force Reduction Factor vs. Skew

Rskew = 8x10-05θ2 - 0.018θ + 1 R² = 0.98

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 15 30 45 60 75 90

Red

uctio

n Fa

ctor

, Rsk

ew

Skew Angle, θ [degrees]

Lab Tests

Numerical Analysis

Field Tests (This Study)

Proposed Reduction Line

Geometry Effects? Field and Lab tests involved W/H ratios of 2.0

Does this ratio impact the results?

Laboratory Wall

2 ft

4 ft

Field Wall

5.5 ft

11 ft

Field Test with 0.9m Backfill - W/H=3.7

11 ft x 5.5 ft high x 15 ft long Pile Cap

0.9m

4 ft Dia. Reinforced Concrete Shaft

12.75 in. Dia. Steel Pipe Piles

2- 600 kip Actuators

Passive Force-Displacement Curves

0 2 4 6 8 10

0

100

200

300

400

500

600

700

800

0

20

40

60

80

100

120

140

160

180

0.00 1.00 2.00 3.00 4.00

Pile Cap Dispalcement [cm]

Long

itudi

nal F

orce

[kN

]

Long

itudi

nal F

orce

[kip

s]

Pile Cap Displacement [in]

0 Degree Skew15 Degree Skew30 Degree Skew45 Degree Skew

0.01

H

0.02

H

0.03

H

0.04

H

0.05

H

0.06

H

0.07

H

0.08

H

0.09

H

0.10

H

Passive Force Reduction Factor vs. Skew

Rskew = 8x10-05θ2 - 0.018θ + 1 R² = 0.98

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 15 30 45 60 75 90

Red

uctio

n Fa

ctor

, Rsk

ew

Skew Angle, θ [degrees]

Lab Tests

Numerical Analysis

Field Tests (This Study)

Proposed Reduction Line

45º Skew with RC Wingwalls

Overall Best Fit – Simplified Equation

00.10.20.30.40.50.60.70.80.9

1

0 15 30 45 60 75 90

Redu

ctio

n fa

ctor

, Rsk

ew

Skew Angle, θ (Degrees)

Shamsabadi & Rollins 2014

Rskew = e(-ϴ/45°)

Summary Relative to Skew Effects Significant decrease in passive force with increase in

skew angle. • Numerical Analysis • 8 Small Scale Lab Tests • 11 Large Scale Field tests

Simple reduction factor can account effect of skew angle on passive force

Reduction factor not much affected by wall W/H ratio Reduction factor not much affected by sand, gravel, or

GRS backfill type Passive force typically mobilized at Δ/H ≈ 3 to 5% Shear resistance largely mobilized with 0.25 inch of

movement at interface

Example Problem Given: Abutment wall 6 ft high and 50 ft wide. Backfill soil is sandy gravel (A-1-a) compacted to 95% of

Modified Proctor density. ( γmoist = 135 pcf) Soil friction angle, φ, of 40º with no cohesion Assume soil/wall friction angle, δ, is 0.7φ = 28º Skew angle, θ, of 30º

Find: (a) Passive Force vs. Deflection Curve (b) Shear Resistance vs. Deflection Curve

Adjustment for Width & Skew

Previously PpH = 28.5 k/ft

50 ft

θ = 30º

For 0º skew condition PpH = (28.5 k/ft) (50ft) = 1425 k

Compute skew reduction factor Rskew= e(-ϴ/45º) = e(-30º/45º) = 0.51

For 30º skew condition PpH = (1425 k)(0.51) = 727 k

PpH

Passive Force-Displacement

50 ft

θ = 30º PpH

PpH

Displacement (in)

For a 6 ft high backwall: Peak at 0.03H = 0.03(6 ft)(12in/ft) = 2.2 in

2.2 in

727 k

= 727k

Shear Force-Displacement

50 ft

θ = 30º For a δ=28º = 0.70φ T = cA + PpHtanδ = 0 + (727 k) tan(28º) = 387k

PpH=727k

T

Displacement (in)

Peak at 0.25 in

0.25 in

387k

T = 387k

Bi-linear Passive Force vs. Displacement

0 2 4 6 8 10

0

500

1,000

1,500

2,000

2,500

0

100

200

300

400

500

600

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Pile Cap Deflection [cm]

Pass

ive

Forc

e [k

N]

Pass

ive

Forc

e [k

ips]

Pile Cap Deflection [in]

0° Skew15° Skew30° Skew45° Skew

0.02

H

0.03

H

0.04

H

0.05

H

Hyperbolic Passive Force vs. Displacement

0 2 4 6 8 10

0

500

1,000

1,500

2,000

2,500

0

100

200

300

400

500

600

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Pile Cap Deflection [cm]

Pass

ive

Forc

e [k

N]

Pass

ive

Forc

e [k

ips]

Pile Cap Deflection [in]

0° Skew15° Skew30° Skew45° Skew

0.02

H

0.03

H

0.04

H

0.05

H

Flowable Fill Abutment Tests γ = 127 lbs/ft3

UCS = 50 to 60 psi

Flowable Fill Abutment Tests

Pp = 0.5γH2B + 2cHB, Passive force for cohesive soil c = UCS/2

Flowable Fill Abutment Tests

Lightweight Cellular Concrete Backfill

γ = 30 lbs/ft3

UCS = 50 to 60 psi

Passive Force-Deflection Curves

0

200

400

600

800

1000

1200

0.00 1.00 2.00 3.00 4.00

Pass

ive

Forc

e (k

ips)

Avg. Pile Cap Displacement (in)

30 Skew

0 Skew

Pp = 0.5γH2B + 2cHB, Passive force for cohesive soil

Lateral Pile Resistance at Abutments Group interaction factors (P-multipliers) Reduction factors for presence of MSE wall face

Pile Group Interaction

Leading Row Piles

Trailing Row Piles

Direction of Loading

Row 1

Row 2

Row 3

H

Lateral Load Analysis for Piles with p-y Curves

Non-linear springs

p

p

p

p

p

y

y

y

y Interval

y

y

y

y

y

1

2

3

4

5

y

P-Multiplier Concept (Brown et al, 1988)

Horizontal Displacement, y

Hor

izon

tal F

orce

/Len

gth,

P Single Pile Curve

Group Pile CurvePSP

PGP = PMULT PSP

9 Pile Group at 5.6 D Spacing

LVDT Tie-Rod Load Cell

Pinned Connection

3x5 Pile Group at 3.3 D Spacing

3x3 Pile Group at 5.6 Dia. Spacing

0

50

100

150

200

250

0 20 40 60 80Avg. Group Deflection (mm)

Avg

. P

ile L

oad

(kN

)

SingleRow 1Row 2Row 3

3x5 Pile Group at 3.3D Spacing

0

50

100

150

200

250

0 20 40 60 80 100

Avg. Group Deflection (mm)

Avg

. Pile

Loa

d (k

N)

SingleRow 1Row 2Row 3Row 4Row 5

P-Multipliers from AASHTO

(b) Trailing Row P-Multipliers

0.0

0.2

0.4

0.6

0.8

1.0

1.2

2 3 4 5 6 7 8Pile Spacing (c-c)/Pile Diam.

P-M

ultip

lier

Row 2-Stiff Clay Rollins et al (2003)Rows 3-5-Stiff Clay-Rollins et al (2003)Row 2-Soft Clay-This StudyRows 3-5-Soft Clay-This Study

Reese et al (1996)

AASHTO (1998)

(a) Leading Row P-Multipliers

0.0

0.2

0.4

0.6

0.8

1.0

1.2

2 3 4 5 6 7 8Pile Spacing (c-c)/Pile Diam.

P-M

ultip

lier

Stiff Clay-Rollins et al (2003)

Soft Clay-This Study

Reese et al (1996)

AASHTO (1998)

P-Multipliers from Tests

Rollins et al., 2005

Abutment Piles near MSE Walls

Abutment Piles Near MSE Walls

MSE Wall Geometry

L

H

S

Plan View Wall decreases lateral pile resistance Pile load increases force on reinforcement

Elevation View

Approaches to the Problem

Increased Cost from Larger Pile Diameter or More Piles

Ignore Soil Resistance

Approaches to the Problem

Increased Cost from Larger Bridge Span

Increase Spacing to Eliminate Interaction

Approaches to the Problem

What should the reduction be?

Estimate a Reduction Factor

Mechanically Stabilized Earth Abutment Wall

MSE Test Wall (20 ft high & 100 ft long)

24 Tests with round, square, & H piles at 2D to 5D

Profile View of Test Layout

L

H

D

Ultimate Design

L

H

S

Layout During Tests

Surcharge

Plan and Elevation View of Test Abutment

Surcharge

100 ft 40 ft 40 ft

20 ft

Strip Reinforcement Welded Wire grid Reinforcement

Elevation View

Plan View

18 ft

15 ft

Cross-Section Through MSE Wall

Surcharge - 600 psfVaries

(2 to 5 ft)

ReactionBeam Reaction

PileWall Panels(5 ft x 10 ft)

18 ft

25 ft

Native Soil

Select Granular Backfill

Random Fill

Test Pile

20 ft

UnreinforcedConcrete Level Pad(6 in. x 12 in)

2 ft

Reinforcing Elements

Pile Testing Sequence

2D 3D 4D 5D 5D 4D 3D 2D 5D 4D 3D 2D 2D 3D 4D 5D

Wire Mat Type Reinforcement Strip Type Reinforcement

12.75” Pipe Piles 12.75” Pipe Piles HP12x74 Piles 12” Square Piles

Total of 31 Tests 15 ft Wall – L/H ≈ 0.9 20 ft Wall – L/H ≈ 0.7

Reaction Beam Reaction Beam Reaction Beam

Nuclear Density Gauge Tests

Typical Test Set-up

Reaction Pile Reaction Beam Pre-cast

Concrete Blocks

Typical Test Set-up

Reaction Pile

Reaction Beam

Test Pile

Pre-cast Block Surcharge

Load Test Photos

Hydraulic Jack Pinned

Connection

Effect of MSE Wall on Lateral Pile Resistance

Pipe Piles with Strip Reinforcement

0

10

20

30

40

50

60

70

0 0.5 1 1.5 2 2.5 3 3.5

Load

(kip

)

Deflection (in)

Reaction3.9D3.1D2.7D1.7D

Square Piles with Welded-Wire Reinforcement

P-multiplier Concept For Proximity of the Wall H

oriz

onta

l For

ce/L

engt

h, P

Horizontal Displacement, y

Single Pile Curve

Group Pile CurvePSP

PGP = PMULT PSP

Pile Away from Wall

Pile Near Wall

nw

aw

aw

Measured and Computed Load-Deflection

0

10

20

30

40

50

60

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Pile

hea

d lo

ad (k

ip)

Pile head deflection (in)

3.9Dp-multiplier = 13.1Dp-multiplier = 0.952.8Dp-multiplier = 0.71.7Dp-multiplier = 0.33

Calibrated p-y curves for pile at 3.9D spacing

P-multipliers back-calculated for closer piles

P-multipliers from All Tests

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6 7 8

P-m

ultip

lier

Normalized Distance , S/D

Previous Tests (L/H=0.9 to 1.2)

SSL (L/H=0.90)

RECo (L/H=0.90)

Reco (L/H=0.72)

SSL (L/H=0.72)

Square (L/H=0.72)

H (L/H=0.72)

Best Fit Line

Pmult = 0.32(S/D) - 0.23

R2 = 0.86

Pmult = 1.0

Effect of Variables on P-multiplier Equation

RED = ribbed strips BLUE = welded wire

RED = L/H of 1.0+ BLUE = L/H of 0.9 GREEN = L/H of 0.7

Not significantly affected by reinforcement type Not significantly affected by L/H ratio

Passive Force References • Duncan, M.J. and Mokwa, R.L. (2001). “Passive earth pressure: theories and tests,”

J. Geotech. & Geoenv. Engrg. ASCE, 127(3), 248-257. • Cole, R.T and Rollins, K.M. (2006). “Passive Earth Pressure Mobilization During

Cyclic Loading.” J. Geotechnical and Geoenvironmental Engrg., Vol. 132, No. 9, 1154-1164.

• Rollins, K.M. and Cole, R.T. (2006). “Cyclic Lateral Load Behavior of a Pile Cap and Backfill.” J. Geotechnical and Geoenvironmental Engrg., ASCE, Vol. 132, No. 9, 1143-1153.

• Rollins, K.M. and Sparks, A.E. (2002) “Lateral Load Capacity of a Full-Scale Fixed-Head Pile Group.” J. Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 128, No. 9, p. 711-723.

• Rollins, K.M., Sparks, A.E., Peterson, K.T. (2000) “Lateral Load Capacity and Passive Resistance of a Full-Scale Pile Group and Cap.” Transportation Research Record 1736, Transportation Research Board, p. 24-32

• Rollins, K. M. and Jessee, S. (2013). “Passive Force-Deflection Curves for Skewed Abutments”. Journal of Bridge Engineering, ASCE, Vol. 18, No. 10, p. 1086-1094

• Marsh, A., Rollins, K.M., Behavior of Zero and Thirty Degree Skewed Abutments.” (2013). Journal of Transportation Research, Transportation Research Board, Washington, DC. Vol. 2363 (Soil Mechanics 2013), p. 12-20

• Shamsabadi, A., ROLLINS, K.M., Kapaskur, M. (2007). “Nonlinear Soil-Abutment-Bridge Structure Interaction for Seismic Performance-Based Design.” J. of Geotechnical and Geoenvironmental Engrg., ASCE, (June 2007) Vol. 133, No. 6, 707-720.

• Rollins, K.M., Scott, E., Marsh, E. (2017). “Geofoam Inclusions for Reducing Passive Force on Bridge Abutments Based on Large-Scale Tests.” Procs. Geotechnical Frontiers, Geotechnical Special Publication 279, ASCE, p. 59-68.

Lateral Pile Group Load References • Rollins, K.M., Olsen, R.J., Egbert, J.J., Jensen, D.H., Olsen, K.G., and

Garrett, B.H. (2006). “Pile Spacing Effects on Lateral Pile Group Behavior: Load Tests.” J. Geotechnical and Geoenvironmental Engrg., ASCE, Vol. 132, No. 10, p. 1262-1271,

• Rollins, K.M., Olsen, K.G., Jensen, D.H, Garrett, B.H., Olsen, R.J., and Egbert, J.J. (2006). “Pile Spacing Effects on Lateral Pile Group Behavior: Analysis.” J. Geotechnical and Geoenvironmental Engrg., ASCE, Vol. 132, No. 10, p. 1272-1283.

• Rollins, K.M., Lane, J.D., Gerber, T. M. (2005) “Measured and Computed Lateral Response of a Pile Group in Sand.” J. Geotechnical and Geoenvironmental Engrg., ASCE Vol. 131, No. 1, p. 103-114.

• Rollins, K.M., Snyder, J.L. and Broderick, R.D. (2005). “Static and Dynamic Lateral Response of a 15 Pile Group.” Procs. 16th Intl. Conf. on Soil Mechanics and Geotech. Engineering, Millpress, Rotterdam, The Netherlands, Vol. 4, p. 2035-2040.

• Rollins K., Budd, R., Luna, A., Hatch, C., Besendorfer, J., Han, J., and Gladstone, R. (2016). “Lateral Resistance of Abutment Piles Near MSE Walls.” International Bridge Conference, Washington, D.C., paper 16-52, 8 p.

• Rollins, K.M. and Nelson, K. (2015). “Influence of pile offset behind an MSE wall on lateral pile resistance.” Procs. XVI European Conference on Soil Mechanics and Geotechnical Engineering: Geotechnical Engineering for Infrastructure and Development, ICE publishing, p. 1163-1168

Lateral Pile Resistance Near MSE Walls • Rollins K., Budd, R., Luna, A., Hatch, C., Besendorfer, J., Han, J., and

Gladstone, R. (2016). “Lateral Resistance of Abutment Piles Near MSE Walls.” International Bridge Conference, Washington, D.C., paper 16-52, 8 p.

• Rollins, K.M. and Nelson, K. (2015). “Influence of pile offset behind an MSE wall on lateral pile resistance.” Procs. XVI European Conference on Soil Mechanics and Geotechnical Engineering: Geotechnical Engineering for Infrastructure and Development, ICE publishing, p. 1163-1168

Questions?

Brigham Young University Campus

Today’s Participants

• Ken Fishman, McMahon and Mann Consulting Engineers, PC, kfishman@mmce.net

• Kyle Rollins, Brigham Young University, rollinsk@byu.edu

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