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Imagination, Good Engineering and Saving MoneyImagination, Good Engineering and Saving Money

Keith Kirkwood, P.Eng.Peter Buckland, C.M., P.E.

International Bridge, Tunnel and Turnpike AssociationManaging in an Era of Changing Economic Times2009 April 19-21San Francisco, CA

Innovative Bearing RetrofitsInnovative Bearing Retrofits

A. Murray MacKay Bridge Halifax, NS, Canada

Client: Halifax-Dartmouth Bridge Commission (IBTTA Member)

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Truss Bearing Retrofit at Main Towers

The Problem: Bearings MalfunctioningThe Challenge: Replace While Minimizing Traffic Disruptions

Main Tower

Side Span Truss

Malfunctioning Bearings

Main Span Truss

Truss Bearing Retrofit at Main TowersTruss Bearing Retrofit at Main Towers

The Solution: Hang Truss From Above on “Pendulum Links”

PendulumLinks

MalfunctioningBearings

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Truss Bearing Retrofit at Main TowersTruss Bearing Retrofit at Main Towers

The Solution:

Bridge Deck RehabilitationBridge Deck Rehabilitation

Saint John Harbour Bridge,Saint John, NB, Canada

Client: Saint John Harbour Bridge Authority (IBTTA Member)

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Bridge Deck RehabilitationBridge Deck Rehabilitation

Year 1:

Traffic Construction

Running

Traffic

Running

Construction Construction

NorthApproach

Ramp B

Ramp AMain and Side SpansSouth Approach

Bridge Deck RehabilitationBridge Deck Rehabilitation

Original Concrete

Hydro-Demolition

Cold Milling

New Asphalt

NewConcrete

Original Concrete

Pass 4 Pass 3

Pass 1Pass 2

Existing Deck

Construction Zone

New Asphalt

Existing Deck

NewConcrete

End of Year 1

ConventionalDemolition

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Bridge Deck Widening

The Problem: Bridge Deck at Capacity(110,000 vehicles/day)

The Challenge: Make four lanes into five,under modern traffic loads

And, oh yeah… Keep Traffic Running!

Port Mann Bridge, Vancouver, B.C.

Bridge Deck WideningBridge Deck Widening

Original:

After Widening:

Approach Spans:

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Bridge Deck WideningBridge Deck Widening

Work Zone Next to Traffic

Bridge Deck WideningBridge Deck Widening

Work Zone Next to Traffic

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Bridge Deck Widening

Main Span Improvements:

• New Steel Barriers• Strengthened Hangers• New Maintenance Walkway• Falcon Nest Platform• Painting of Box Girder

Survey and Analysis “Health” Study

• Suspension bridge health can be investigated by “survey and analysis” technique

• Detective work required to explain differences

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Truss Member Replacement While Traffic Running

Three Nations Bridge Crossing, Canada - USA

Client: Seaway International Bridge Corporation (IBTTA Member)

The Problem: Stiffening truss overloaded by modern traffic

The Solution: Replace chords with high strength steel

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Suspension Bridge Full Deck Replacement

Lions’ Gate Bridge, Vancouver, BC, Canada

The Challenge:

Replace corroded deck Widen traffic lanes Widen sidewalksProvide barriers Provide pavingProvide drainsReduce maintenanceIncrease load capacity Improve aerodynamic stabilityImprove roadway sightlines

The Constraints:The Constraints:Maintain same weightCarry traffic during constructionReplace each section in 10 hours 20:00 to 06:00Very limited access

The Solution:The Solution:Replacement of Entire Suspended

Span Structure

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12 200

3 SP'S @ 2900 = 8700 13001300

Original Cross Section

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2700

12 192

16 762

2000

27003 LANES @ 3556 = 10 668

ORNAMENTALLIGHTS

HANDSTRANDS

Completed Cross Section

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Wind Tunnel Testing

First Deck Panel Replacement

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First Deck Panel Replacement

Panel Replacement

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Half-way There!

A New Driver Experience!

Original Deck Replacement Deck

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Suspension Bridge Strengthening

Hagwilget Bridge, Terrace, British Columbia

Suspension Bridge Strengthening

The Challenge:•Increase loading on bridge from 1 x 16 Ton Truck to 2 x 60 Ton Trucks

The Constraints:•Keep vehicle open during except for 10 hours at night•Bridge always available for ambulance passage.

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Suspension Bridge Strengthening

The Solution:•Shorten hangers to deflect deck upwards.

Summary

• Innovative engineering can save bridge owners money via:

• Decreased capital costs• Decreased maintenance costs• Minimizing effects on tolls by minimizing disruption to traffic.

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Acknowledgements

• Halifax-Dartmouth Bridge Commission•Mr. Steve Snider, General Manager and C.E.O.•Mr. Jon Eppell, P.Eng., Bridge Engineer

• Saint John Harbour Bridge Authority•Mr. Ken Anthony, General Manager

• Seaway International Bridge Commission•Mr. Rik Saaltink, General Manager

Thank you!

Presentation OutlinePresentation Outline

• Innovative Bearing Retrofits• Bridge Deck Rehabilitation• Bridge Deck Widening• Suspension Bridge Full Deck Replacement• Truss Member Replacement While Traffic Running• Suspension Bridge “Health” Determination

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10 hours per night, plus always access to hospital

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Originally, load factor = 1.75R≥1.75(D+L)

Now0.9R≥1.1Df+1.5Dw+1.7L

For an existing bridge0.9R≥1.1Df+1.2Dw+1.65L

Bridge Deck RehabilitationBridge Deck Rehabilitation

Year 1:

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Bridge Deck RehabilitationBridge Deck Rehabilitation

Year 2:

Bridge Deck RehabilitationBridge Deck Rehabilitation

Year 2:

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Bridge Deck RehabilitationBridge Deck Rehabilitation

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