Montana Truss Rehabilitation Projects Lozeau Bridge over the Clark Fork Dearborn River High Bridge Van Buren Street over the Clark Fork

Lozeau Bridge Over the Clark Fork Lozeau Bridge Near Superior, Montana 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

Column Encasement or Replacement Lozeau Bridge 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. Challenges and Solutions

Need to Raise and Support Truss To Repair or Replace Substructure Units and Bearings No End Floor Beams Can’t 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

Column Encasement or Replacement Lozeau Bridge 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 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

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

Dearborn River High Bridge Dearborn River High Bridge Near Augusta, MT 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

Rock Embankment Stabilization Dearborn River High Bridge Existing Abutment was founded on an unstable rock outcropping Unstable rock mass was threatening existing columns Challenges and Solutions

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

Need to Raise and Support Truss Stabilize Rock Slope at End Replace all Substructure Units and Bearings Can’t 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 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 Challenges and Solutions

Drilled shaft Excavation at Abutment No. 5 Dearborn River High Bridge Challenges and Solutions

Abutment No. 5 Dearborn River High Bridge Challenges and Solutions

Abutment Replacement & Rock Stabilization Dearborn River High Bridge Challenges and Solutions

Abutment Replacement & Rock Stabilization – Before & After Dearborn River High Bridge Challenges and Solutions

Substructure Replacement Reusing the existing stone in the new abutment Dearborn River High Bridge Challenges and Solutions

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

Replace / Repair Old Bearings New Elastomeric Bearings Dearborn River High Bridge New Expansion Bearing Sole Plate 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 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 Challenges and Solutions

OVERCOAT PAINT SYSTEM 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 Dearborn River High Bridge Challenges and Solutions

Van Buren St. Over the Clark Fork Van Buren Street Bridge - Missoula, MT Built 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

Miscellaneous Truss Repairs – Eyebar Hanger Van Buren Street Pedestrian Bridge Challenges and Solutions

Miscellaneous Truss Repairs - Verticals Van Buren Street Pedestrian Bridge Challenges and Solutions

Miscellaneous Truss Repairs – Top Flange Repair Van Buren Street Pedestrian Bridge 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 Challenges and Solutions

End Frame Replacement Van Buren Street Pedestrian Bridge Challenges and Solutions

Heat Straightening & Heat Shortening The existing eye bars elongated over the years Performed heat shortening to remove slack Left cables in place Van Buren Street Pedestrian Bridge 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 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 Challenges and Solutions

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.

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

Questions?

Pictures Lozeau Bridge

Pictures

Dearborn River High Bridge Pictures

Dearborn River High Bridge Pictures

Dearborn River High Bridge Pictures

Dearborn River High Bridge Pictures

Dearborn River High Bridge Pictures

Dearborn River High Bridge Pictures

Van Buren Street Bridge Pictures

Van Buren Street Bridge Pictures

Van Buren Street Bridge Pictures

Van Buren Street Bridge Pictures