Montana Truss Rehabilitation Projects

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Montana Truss Rehabilitation Projects

• Lozeau Bridge over the Clark Fork
• Dearborn River High Bridge
• Van Buren Street over the Clark Fork

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Lozeau Bridge Over the Clark Fork

• Constructed 1924 Near Thompson Falls, MT
• Moved Reconstructed During WWII in 1944
• USFS With Permission From the War Department
• Used POW Labor, Local Aggregate
• Reconstructed in 1998 by MDT

• Lozeau Bridge Near Superior, Montana

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Challenges and Solutions

• Column Encasement or Replacement

• Existing columns had been patched in places
• Original intent was to repair spalled/unsound
  areas
• During construction, discovered some areas that
  were far worse than expected.

Lozeau Bridge
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Challenges and Solutions

• Need to Raise and Support Truss

• To Repair or Replace Substructure Units and
  Bearings
• No End Floor Beams
• Cant Jack Against Bottom Chord
• Solution Use Jacking Frame
• Lift Truss From Above Using Cradle under Truss
  Pins
• Supports Stringers From Jacking Frame Easily

Lozeau Bridge
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Challenges and Solutions

• Column Encasement or Replacement

• Superstructure was temporarily supported by a
  jacking frame
• Columns and cap were completely replaced at the
  end piers
• Columns were jacketed with a reinforced concrete
  shell at the center pier

Lozeau Bridge
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Challenges and Solutions

• Attach New Railing to Lightweight Truss or Deck

• Attach Truss Rail Posts to Steel Stringers and
  Curbs
• Railing Independent of Truss
• Approach Spans Rail Posts Bolted to Curbs and
  Stringers

Lozeau Bridge
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Challenges and Solutions

• Timber Decks - Maintain Historic Deck Material
  Type and Minimize Dead Load

• Pentachlorophenol
• Running Planks
• 5 1/8 Glued-Lam Deck
• Nail Lam Deck at End Spans
• BMP for Use of Treated Wood in Aquatic
  Environments

Lozeau Bridge
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Dearborn River High Bridge

• Built 1897 by the King Bridge Co. Cleveland, OH
• Lewis and Clark County, Before Highway Dept.
• Unusual Mid-Deck Truss, Only One Remaining?
• Reconstructed in 2003 by MDT
• Venetian Red

• Dearborn River High Bridge Near Augusta, MT

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Challenges and Solutions

• Rock Embankment Stabilization

• Existing Abutment was founded on an unstable rock
  outcropping
• Unstable rock mass was threatening existing
  columns

Dearborn River High Bridge
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Challenges and Solutions

• Rock Embankment Stabilization

Caisson knocked partially out from under bearing
Unstable rock mass
Dearborn River High Bridge
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Challenges and Solutions

• Need to Raise and Support Truss

• Stabilize Rock Slope at End
• Replace all Substructure Units and Bearings
• Cant Jack Against Bottom Chord
• Solution Deck is to be Removed and Replaced,
  Remove Lightweight Truss to Bank
• Use Special Bolted Lifting Points and Spreader
  Beams

Dearborn River High Bridge
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Challenges and Solutions

• Abutment Replacement Rock Stabilization

• Remove unstable rock mass by controlled blasting
• Stabilize slope by rock bolting
• Socket the new abutment into competent rock
• Stabilize approach with gabion baskets

Dearborn River High Bridge
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Challenges and Solutions

• Drilled shaft Excavation at Abutment No. 5

Dearborn River High Bridge
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Challenges and Solutions

• Abutment No. 5

Dearborn River High Bridge
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Challenges and Solutions

• Abutment Replacement Rock Stabilization

Dearborn River High Bridge
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Challenges and Solutions

• Abutment Replacement Rock Stabilization
  Before After

Dearborn River High Bridge
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Challenges and Solutions

• Substructure Replacement

• Reusing the existing stone in the new abutment

Dearborn River High Bridge
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Challenges and Solutions

• Substructure Replacement

Reusing the existing stone in the new approach
span footings
Dearborn River High Bridge
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Challenges and Solutions

• Replace / Repair Old Bearings

New Elastomeric Bearings
New Expansion Bearing Sole Plate
Dearborn River High Bridge
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Challenges and Solutions

• Timber Deck - Maintain Historic Deck Material
  Type and Minimize Dead Load

• Creosote
• 3 1/8 Glued-Lam Deck
• Transverse Longitudinal
• BMP for Use of Treated Wood in Aquatic
  Environments
• Most Agencies Do Not Use Creosote Now

Dearborn River High Bridge
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Challenges and Solutions

• Attach New Railing to Lightweight Truss or Deck

• Longitudinal Decking - Attach Posts to Floor
  Beams for Approach Spans
• Transverse Decking - Attach Posts to Structural
  Tubes in Plane of Deck Between Deck Panels
• Rail Posts Independent of Truss

Dearborn River High Bridge
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Challenges and Solutions

• OVERCOAT PAINT SYSTEM

Dearborn River High Bridge

• Restored original color of bridge Venetian
  Red
• High pressure water blast and mechanical
  cleaning
• Moisture cure urethane overcoat system
• Make sure paint system is compatible with
  existing paint

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Van Buren St. Over the Clark Fork

• Built 1892-3 on Higgins Avenue
• Washed out in Flood 1908
• Salvaged Moved Upstream to Van Buren Street
• Sidewalks Outside Truss Removed
• Converted to Pedestrian Use in 1975
• Reconstructed by Missoula County in 2004

• Van Buren Street Bridge - Missoula, MT

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Challenges and Solutions

• Miscellaneous Truss Repairs Eyebar Hanger

Van Buren Street Pedestrian Bridge
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Challenges and Solutions

• Miscellaneous Truss Repairs - Verticals

Van Buren Street Pedestrian Bridge
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Challenges and Solutions

• Miscellaneous Truss Repairs Top Flange Repair

• All of the top flanges on the built-up floor
  beams were severely rusted and needed
  replacement.
• The existing flange angles were removed and used
  as a template to drill holes in the new angles

Van Buren Street Pedestrian Bridge
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Challenges and Solutions

• End Frame Replacement

Van Buren Street Pedestrian Bridge
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Challenges and Solutions

• Heat Straightening Heat Shortening

Van Buren Street Pedestrian Bridge

• The existing eye bars elongated over the years
• Performed heat shortening to remove slack
• Left cables in place

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Challenges and Solutions

• Timber Decks - Maintain Historic Deck Material
  Type and Minimize Dead Load

• Penta in Light Oil for Pedestrian Usage
• 3 1/8 Glued-Lam Deck
• Re-sawn for Traction
• BMP for Use of Treated Wood in Aquatic
  Environments

Van Buren Street Pedestrian Bridge
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Challenges and Solutions

• Attach New Railing to Lightweight Truss or Deck

• Attach to Steel Stringers
• Independent of Deck or Truss
• Allows Easy Future Deck Replacement
• Note Attachment of Decorative Light-posts at
• Floor-beam Locations.

Van Buren Street Pedestrian Bridge
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Construction Costs

• Lozeau Bridge 1998 Total Cost
  1,500,000 190 / Sq. Ft.
• Dearborn R. High Br. 2003 Total Cost
  1,000,000 250 / Sq. Ft.
• Van Buren Br. 2004 Total Cost
  350,000 60 / Sq. Ft.

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Design Resources

• Heat Straightening - Holt
• Heat Shortening Details and Specs AREMA and Old
  DOT Standards
• Old Steel Sections - Old Books
• AASHTO

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Questions?
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Pictures

• Lozeau Bridge

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Pictures

• Lozeau Bridge

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Pictures

• Dearborn River High Bridge

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Pictures

• Dearborn River High Bridge

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Pictures

• Dearborn River High Bridge

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Pictures

• Dearborn River High Bridge

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Pictures

• Dearborn River High Bridge

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Pictures

• Dearborn River High Bridge

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Pictures

• Van Buren Street Bridge

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Pictures

• Van Buren Street Bridge

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Pictures

• Van Buren Street Bridge

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Pictures

• Van Buren Street Bridge