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Michigan DOT

Bridge Management System

Presented to Domestic Scan on Bridge Management - Webinar

November 19, 2009

Dave Juntunen Engineer of Bridge Operations

Construction & Technology DivisionMichigan Department of Transportation

Michigan DOT

Bridge Management System

Presented to Domestic Scan on Bridge Management - Webinar

November 19, 2009

Dave Juntunen Engineer of Bridge Operations

Construction & Technology DivisionMichigan Department of Transportation

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Michigan DOTMichigan DOT

Michigan has 10,800 Bridges

State is divided into Seven Regions

Michigan has 10,800 Bridges

State is divided into Seven Regions

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Project Selection Process•Coordinate w/Other Systems

•Call for Projects•Scoping

•Programming

Construction•Replacement•Rehabilitation

•Preventive Maintenance•Track Project Cost

Design•Preliminary Design

•Final Design•Engineers Estimate

Bridge Management System•Set Goals

•Develop Strategies•Deterioration Modeling

•Project Cost•Preservation Rules

•Network ManagementBridge Inspection

•Safety and Evaluation•Data Collection

•Data Management

Asset Management

Asset ManagementAsset Management

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Michigan DOT Goals Established in 1998

Michigan DOT Goals Established in 1998

• Immediately address the needs of 100% of structures of critical concern

• 95% of freeway bridges in good or fair condition by 2008

• 85% of non-freeway bridges in good or fair condition by 2008

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Performance Measures

• Performance Measure - A quantifiable, enduring measure of outcomes, outputs, efficiency, or cost-effectiveness. In general, measures should be related to an agency's mission, goals and programs, and should not merely measure one-time or short-term activities (i.e. - should be ongoing or periodic measurement).

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What is a need indicator?

• Data collected that identifies a specific work type or activity.

• Example – Deck concrete spalling or delaminating identifies deck patching

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•• Condition goals based Condition goals based upon NBI condition upon NBI condition ratingsratings

•• Rating of Rating of ““Major Major ElementsElements””–– Deck, superstructure, Deck, superstructure,

and substructureand substructure–– ““Weakest LinkWeakest Link””

determines rating for determines rating for bridgebridge

Michigan DOTMichigan DOTPerformance MeasuresPerformance Measures

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Bridge Condition Ratings

0

200

400

600

800

1000

1200

1400

Num

ber o

f Brid

ges

1 2 3 4 5 6 7 8 9

NBI Rating

GoodFairPoorSerious or Critical

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Performance MeasureMonitor Number of Bridges In Each

Condition State

MDOT All Bridges

0

500

1000

1500

2000

0 1 2 3 4 5 6 7 8 9NBI Rating

Num

ber o

f Brid

ges

1998199920002001200220032004200520062007

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Monitoring Progress Towards Goals

Statewide - Bridge Condition

60%

65%

70%

75%

80%

85%

90%

95%

100%

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Year

Perc

ent B

ridge

s G

ood/

Fair

Con

ditio

n

Freeway Measured Non-Freeway MeasuredFreeway Forecast Non-Freeway Forecast

Goal - 95% of Freeway Bridges in Good/Fair Condition

Goal - 85% of Non-Freeway Bridges in Good/Fair Condition

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“Mix of Fixes” Strategy”

• Replacement – NBI rating of 4 or less• Rehabilitation – NBI rating between

typically 4 and 5• CPM - Capital Preventive Maintenance.

NBI rating typically 5 or 6• MDOT Allocates 20% Funds to

preventive Maintenance, 30% rehabilitation, and 50% Replacement

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Michigan’s Bridge data

• National Bridge Inspection (NBI)– 0-9 rating scale

• AASHTO Commonly Recognized (CoRe) Elements (Pontis)

• Inspector Recommendations

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NBIBridge Safety Inspection Report (BSIR)

• Strengths– Well understood– Well accepted– Shows criticality of major elements– Comments (descriptive)– Clearly defines good, fair, poor

• Weaknesses– Does not distinguish categories within major elements

(bare deck or rigid overlay)– No quantities– Entire portion of element in one condition state– Comments (can not be queried)

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Pontis (CoRe Elements)• Strengths

– Distinguishes categories within major elements (ex. - bare deck or rigid overlay, Unpainted beams or painted)

– Has quantities – Portions of element in different condition states (descriptive) – Flexible architecture to data base structure (can easily add new

elements.)– Smart flags, sub elements– Designed for computerized linear analysis

• Weaknesses– Not as well understood– Not very often being used in business process– Does not show criticality of need very well– No Comments (descriptive)– Variable number of condition states confusing– Good, fair, poor not immediately apparent

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0

200

400

600

800

1000

1200

1400Nu

mbe

r of

Brid

ges

1 2 3 4 5 6 7 8 9

NBI Rating

Deterioration

Critical, Serious, Poor Fair Good, ExcellentDAJ 10/27/04

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Performance MeasureMonitor Bridge Deterioration Rate

Deterioration RateStatewide Trunkline Bridges

0

50

100

150

200

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Year

Num

ber B

ridge

s G

oing

fro

m G

ood/

Fair

to P

oor Linear Fit

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Replacement Projects

• Deck Replacement• Superstructure

Replacement• Bridge Replacement

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0

200

400

600

800

1000

1200

1400

Num

ber o

f Brid

ges

1 2 3 4 5 6 7 8 9

NBI Rating

Replacement ($1.2 - $1.8 Million)

Critical, Serious, Poor Fair Good, ExcellentDAJ 10/27/04

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Rehabilitation Projects

• Deck overlays• Superstructure

Repairs• Substructure Repairs

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0

200

400

600

800

1000

1200

1400

Num

ber

of B

ridge

s

1 2 3 4 5 6 7 8 9

NBI Rating

Rehabilitation ($500 - 700 Thousand)

Critical, Serious, Poor Fair Good, ExcellentDAJ 10/27/04

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Preventive Maintenance Projects

• Joint Replacements• Pin & Hanger

Replacements• Complete Painting• Zone Painting• Epoxy Overlays• Deck Patching• (many more)…

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0

200

400

600

800

1000

1200

1400Nu

mbe

r of

Brid

ges

1 2 3 4 5 6 7 8 9

NBI Rating

Preventive Maintenance ($200 - $300 Thousand)

Critical, Serious, Poor Fair Good, ExcellentDAJ 10/27/04

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Goals and Objectives of Preventive Maintenance

• Slow the deterioration rate of bridges and bridge elements.

• Maintain population of bridges in fair condition (prevent them from becoming poor).– Performance Measure – Number of bridges

entering poor category.• However, Bridges in poor and serious condition

also need PM

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Transition Probabilities also work very well with the NBI ratings

When the entire element is in one condition state, you can monitor the transition probability that the element will drop more than one condition state. Example – Above 57% bridges that were rated 9 remained 9, 35% dropped to 8, and 8% dropped to 7.

Probability stay in that condition state (highlighted yellow)

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Management of MDOT’s “Big Bridges”

• Complex bridges, including movable bridges, post tensioned segmental concrete bridges, and bridges with larger deck area (over 100,000 square feet) are inspected and managed by a statewide “Bridge Operations Unit” based out of Lansing.

• Goal is to always maintain these bridges in good or fair condition

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Convert Transition Probability to Deterioration Rate for Display Purposes

and Comparison.

Deterioration CurveMDOT Freeway

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1225

3760

0123456789

0 10 20 30 40 50 60 70Years

NBI R

atin

g

nT1

5.

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Bridge Decks

• Number one overarching need Indicator

• The condition of bridge decks most often drive bridge projects.

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Bridge Deck Preservation Matrix

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Need Indicators are Deck Top and Bottom Surface Condition

• Top Surface– 2 to 5% - deck patch, epoxy

overlay– 5% to 15% - deck patch– > 15% - rigid overlays, HMA

overlays

• Bottom Surface– < 10% - deep overlay– 10% to 30% shallow

overlay– > 30% replace deck.

For more information see MDOT Bridge Deck Preservation Matrix

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We are also working on better need indicators for delaminated rigid

overlays

We often have bridge decks having rigid overlays (concrete, latex modified, or silica-fume) having very small percentage of spalls (< 2%) but having large percentage of delaminations (30% plus).

Question – How long will it take delaminated area to spall?

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Bridge Condition Forecast System• Evaluates different mix of fixes (PM, Rehab, and

Replacement• Compares different yearly budgets• Uses average cost per deck area• Deteriorates population of bridges using transition

probabilities• User sets which bridges will be worked on and what end

result is Bridge Condition Forecast SystemMDOT - Freeway Bridges

70.00%

75.00%

80.00%

85.00%

90.00%

95.00%

100.00%

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Year

Per

cent

Bri

dges

in F

air o

r Goo

d C

ondi

tion

measured Current Move Ahead (From SLRP)

Freeway Bridge Goal - 95% Good or Fair

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Pontis CalibrationComparison of Pontis Selected Projects vs

Actual Let Projects

Identify Possible Projects, Work Types and Estimate of

Cost

Identify Possible Projects, Work Types and Estimate of

Cost

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Detailed Scopes

• The routine (visual) bridge inspection is not enough to determine actual bridge project needs.

• Chain drag bridge deck• Sound concrete surfaces• Measure section loss of corroded beams• Compare costs of different fixes

(sometimes using life cycle cost analysis)

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Thank You