AGC NYS Construction Industry Conference 10-21-14...Performance Tests Continued Before After GRS Fundamentals 0.5 ksf (25 kPa) 3.1 ksf (148 kPa) 10/21/2014 4 4.1 ksf ... Hydraulic

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Efficiency through technology and collaboration

GRS IBS28th AnnualConstruction Industry Conference December 9-11, 2014Saratoga Springs, New York

Agenda Topics

• Overview of GRS IBS technology• Implementation progress • Addressing implementation hurdles• Example projects

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Audience Questions/Discussion

• How familiar are you with the IBS?• Has the IBS been implemented in your area?• If not what are some of the barriers?

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Evolution of Reinforced Soil

Great Wall of China

Great Ziggurats

GRSUSFS Walls

Steel strips (MSE)

MSE Wall Specs

1980Generic Frictional Connection

Reinforced Soil Foundation

Abutments and Piers

Rock Fall Barriers

Arches

Integrated Bridge System

1000 BC

200 BC

1970

1990

2000

2010

Geosynthetics

Negative Batter Walls

1960

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What is and why use GRS IBS?What is GRS IBS?• GRS-IBS is an accelerated

construction technique for bridge systems that utilizes alternating layers of compacted granular fill and geosynthetic reinforcement.

Why use GRS IBS?• Up to 60% lower costs• Construction time in weeks vs months• Smooth transition eliminating the

“bridge bump”

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GRS IBS – Cross Section

6Image source: FHWA

GRS - Composite Material

Concrete• Aggregate• Water• Cement

GRS• Aggregate

• Closely-spaced geosynthetics

7Image source: FHWA

GRS IBS - Composite Design

Concrete Abutment• Steel reinforcement

provides tensile strength• Spacing and sizing of

reinforcement plays a role in strength and serviceability

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As

d

c

εs

0.0030

C = 0.85f’cab

0.85f’c

b

a = β1c

T = Asfy

d-a/2

Image source: FHWA

GRSMSE

Sv = 32” 28” 24” 20” 16” 12” 8” 4”

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GRS IBS - Composite Design

GRS Abutment• Geosynthetic reinforcement provides tensile strength

and added compressive strength• Facing, as well as spacing and properties of

reinforcement play a role in strength and serviceability

9Image source: FHWA

Performance Tests Continued

Before After

GRS Fundamentals

0.5 ksf(25 kPa)

3.1 ksf(148 kPa)

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4.1 ksf(196 kPa)

5.9 ksf(282 kPa)

8.5 ksf(407 kPa)

11.3 ksf(541 kPa)

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13.9 ksf(666 kPa)

16.7 ksf(800 kPa)

18.1 ksf(867 kPa)

Performance Test2400 lb/ft @ 8” SpacingNo CMU FacingA-1-a Material

Pre- Post-

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0

2

4

6

8

10

12

14

16

0 5000 10000 15000 20000

Ver

tical

Str

ain

(%)

Applied Pressure (psf)

Tf = 2400 lb/ftSv = 8-inchesNo CMU facing

GRS IBS – Implementation Progress 192 Bridges nationally in 44 states including PR and DC ‐ September 2014

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No GRS projects

Federal & local project

Only Federal agency projects

State DOT utilizing GRS IBS

CA

AZ

CO

NM

TX

OK AR

LA

MO KY

AL GA

FL

VA

OH

MI

VT

AK

MT

NV

MEWA

OR

UTKS

IDWY

ND

SD

MN

NE

WI

IAIL

IN

MS

TNSC

NC

WV

PA

NY

CT

DE

MD

DC

MANH

PR

HI

RI

6

2

8

1

5

4

1

1

8

3

3

33

1

1

2

15

1

2

165

1

1

8

11

2

5

3

1

6

2

3 4

1

1

33

2

2

4

4

1

1

NJ4

1

Image source: FHWA


• What is the biggest impediment to deployment of the IBS?

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GRS IBS - “Barriers”= Design Considerations

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Design Considerations for GRS IBS• Use of shallow foundations

– Serviceability (e.g. settlement)– Scour of abutments at water crossings

• Facing durability and aesthetics• Seismic performance• Others?

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GRS IBS - Design Considerations

Use of Shallow Foundations• Reluctance primarily due to perceived issues with

settlement and scour– Restrictive tolerable settlement criteria– Current state-of-practice– Institutional culture and biases, etc.

25Image source: FHWA


Serviceability with GRS IBS• GRS IBS can be built over a variety of foundation

soils: competent or improved• Settlement of foundation soils must be estimated

regardless of foundation type

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Project Example: IL – Great Western Trail over Grace St. (2011)Use of stone columns to improve foundation soils

27Image source: FHWA and Village of Lombard

Project Example: OH – Tiffin River Bridge (2009)

Abutment built on over-consolidated clays

28Image source: Defiance County Ohio

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Tiffin River Bridge – Settlement vs. Time

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Foundation settlement

TotalSettlement

Abutment compression

Almost4 years

Image source: FHWA


Serviceability with GRS IBS• GRS abutments have

predictable deformation• A clear space between

the abutment and superstructure is designed to tolerate long-term deformations



Serviceability with GRS IBS: • Creates a smooth transition from the approach to

the bridge, reducing rider discomfort and increasing long-term bridge performance


Paint striping between approach and concrete bridge deck has not cracked

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Image source: Defiance County ,Ohio

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GRS abutments have experienced floods and continues to have good performance

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Debris impact and high waters, but no facing or abutment damage

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Built in a tidal area

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Project Example: ME – Knox County Beach Bridge (2013)

Image source: Town of North Haven, ME36

Project Example: ME – Knox County Beach Bridge (2013)

Image source: Town of North Haven, ME

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FHWA Hydraulic Design Reference Documents

• HDS-7 Hydraulic Design of Safe Bridges (2012)• HEC-18 Evaluating Scour at Bridges (2012)• HEC-20 Stream Stability at Highway Structures (2012)• HEC-23 Bridge Scour and Stream Instability

Countermeasures: Experience, Selection, and Design Guidance (2009)- Two volumes

Available at:www.fhwa.dot.gov/engineering/hydraulics/

FHWA Hydraulic Toolbox with scour calculator also available (/software)

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KEY CONSIDERATIONS IN HYDRAULIC DESIGN1. Design Event and applicable criteria / regulations2. Adverse flow conditions3. Channel stability4. Potential scour depths and foundation elevation5. Designed scour countermeasures

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Determine Design Flood Frequencies

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FHWA Guidance per HEC-18 (2012) Tables 2.1 and 2.3

Hydraulic Design Flood Frequency, QD

Scour Design Check Flood Frequency, QC

Countermeasure Design Flood Frequency, QCM

Q10 Q50 Q50

Q25 Q100 Q100

Q50 Q200 Q200

Q100 Q500 Q500

Hydraulic Design Flood Frequency selected based DOT policyScour Design Frequency : For shallow foundations the check flood is the basis for scour analysis and foundation design (For a Q25Hydraulic Design Flood, Q100 is the Scour Design Flood) Countermeasures : For a Q25 Hydraulic Design Flood Q100 is the Countermeasure Design Flood

Consider Potential for Adverse Flow Conditions

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Significant Flow Contraction Skewed Crossing

More comprehensive analysis is often needed for these conditions

Overtopping and Flanking PotentialHigh Velocity Flow

Image source: FHWA

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Evaluate Channel Stability and Suitability of GRS

• Assess the present state of the stream and evaluate the potential for long-term changes in bed elevationConsider the following:– Stream characteristics– Lateral bank erosion– Notable aggradation or degradation– Flood history (existing bridge history)– Changes in watershed / hydrology

• Analyze stream stability based on assessment (HEC-20 Chapter 6)

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Perform Scour Evaluation• Long-term degradation (LTD): Natural changes in

streambed elevation (HEC-18 Ch. 5)• Contraction Scour (CS): Removal of bed material

across the entire channel that results from contraction of flow and increased velocity (HEC-18 Ch. 6)

CS

LTD


RSFReinforced Soil

Foundation (RSF)

Set Abutment Foundation Elevation andDesign Countermeasures

CS

LTD

1. GRS foundations set at elevation of Contraction Scour + Long Term Degradation.

2. Countermeasures designed per HEC-23 (DG 18) (Geometry, riprap size, and extents)

3. Any deviation from the Interim Implementation Guide will result in the bridge being considered scour critical and require a monitoring “plan of action” developed and implemented by the bridge owner

3 x D50

(>5ft)3

1

1ft

Geotextile Filter Fabric

3 xD50 +1ft


RSFRSF

Set Abutment Foundation Elevation andDesign Countermeasures

CS

LTD

Fill narrow gaps between abutment countermeasures with

riprap 2 x D50 thick

Fill narrow gaps between abutment countermeasures with

riprap 2 x D50 thick


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Facing Durability & Aesthetics• There have been issues with

the durability of dry cast concrete in the past, leading to distrust of these products– FHWA led TPF study (2007) – Revised material

specifications were developed to address issues

• Any facing material is possible with GRS IBS



Facing Durability & Aesthetics• Option to select other facing types to address either

durability or aesthetic concerns.– CMU (solid and hollow split-face)– Modular block (solid and hollow)– Large wet cast blocks– Panels– Sheet piles

• Impact on cost and constructability

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• Types of Facing Used for GRS IBS

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Sheet Pile

CMU

Pre-cast panelLarge Wet Cast Block

SRW

Image source: Town of North Haven, ME

Image source: PA DOT

Image source: Utah DOT Image source: Scott County, IA

Image source: Colorado DOT

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• Types of modular blocks

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Image source: Utah DOT

Image source: Delaware DOT Image source: Wisconsin DOT

Image source: Delaware DOT


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• Seismic design– Seismic loads are accounted for in the

external stability design of the IBS– GRS abutments, and reinforced soil in

general, perform very well under seismic conditions

• Large-scale shake table testing• Numerical modeling• Post-event visual observations• “Connection” passive resistance > DLRXN

– Longitudinal passive resistance > DLRXN X 2– Transverse passive resistance > DLRXN

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GRS IBS - “Barriers”= Design Considerations Project Example: HI – Saddle Road Bridge (2012)

Designed for PGA x Fpga ground acceleration (PGA=0.6g Fpga=1.0 )


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Project Example: UT – I-84 Echo Bridge (2013)

First GRS IBS on the Interstate; utilized SIBC


Summer 2014• No bumps• No cracks• Excellent performance

Constructed summer 2013• No approach slab• ADT > 8,000• Truck ~ 40%


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GRS IBS – Design and Construction Guidance



• What type of implementation activities would you find helpful to deploy the GRS IBS in your area?

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IBS – Example Projects from 25 states

• Different types of:– crossings– Superstructures– Geometries – Facings– Fill materials

• Geosynthetics• Designers, from in-house to consultant• Construction delivery method, in-house to

contracted

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OH – Bowman Rd Bridge (2005)

58Image source: Defiance County, OH

NY – CR 38 St. Lawrence County (2013)

59Image source: St. Lawrence, NY

PA – Sandy Creek Bridge (2013)

60Image source: PA DOT

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WI – STH 40 Bloomer, WI (2012)

61Image source: WI DOT

DE – Chesapeake City Road over Guthrie Run (2013)

62Image source: Delaware DOT

SD – 8th Street Bridge, Custer (2014)

63Image source: SD DOT

HI – Kauaula Stream Bridge (2012)

64Image source: HI DOT

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CA – Disney Bridge, Sequoia National Park (2012)


MT – SR89, Dupuyer

66Image source: MT DOT

MD – Allegany County (2014)


OK – Kay County


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MI – Keefer Rd. (2014)


NE – Sand Creek (2014)


VA – Towlston Rd, Great Falls (2014)


WV – VA Hospital, Clarksburg (2013)

72Image source: WV DOT

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SC – Airline Rd, Anderson County (2014)

73Image source: Anderson County, SC

WA – Cheney Plaza Bridge (2014)

74Image source: Spokane County, WA

FL – CR 107 over Lanceford Creek (2014)

75Image source: Nassau County, FL

MN - CR 55 over MN Southern Railway (2013)

76Image source: Rock County, MN

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MA – SR 7A over Housatonic RR (2014)

77Image source: FHWA and MA DOT

PR – Yauco PR2 (2014)

78Image source: PRHTA

MO – Route B Bridge Over Business Loop 70


FHWA’s Geosynthetic Reinforced Soil Integrated Bridge System (GRS IBS) TeamName Office Phone Email

Daniel Alzamora Resource CenterLakewood, CO

(720) 963-3214 [email protected]

Mike Adams Turner FairbankMcLean, VA


Jennifer Nicks Turner FairbankMcLean, VA


Khalid Mohamed Office of Bridges and StructuresWashington, DC


Scott Hogan Resource CenterLakewood, CO


Derrell Manceaux Resource CenterLakewood, CO


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Additional Resources

www.fhwa.dot.gov/everydaycounts

• Design and Construction Guidelines• Construction Training Video• Standard Plans• Sample Guide Specifications• Presentations• FAQs• Case Histories• Event Calendar

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Questions and Comments

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How can we help you help us be successful in implementing GRS IBS in your state?

Image source: PA DOT