Montana Truss Rehabilitation Projects

1. MontanaTruss Rehabilitation Projects Lozeau Bridge over the Clark Fork Dearborn River High Bridge Van Buren Street over the Clark Fork

2. 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

3. 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

4. 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

5. Column Encasement or Replacement Challenges and Solutions • 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

6. 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

7. 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

8. 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

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

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

11. 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

12. 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

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

14. Abutment No. 5 Challenges and Solutions Dearborn River High Bridge

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

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

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

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

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

20. 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

21. 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

22. 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

23. 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

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

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

26. 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

27. Challenges and Solutions • End Frame Replacement Van Buren Street Pedestrian Bridge

28. 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

29. 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

30. 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

31. 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.

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

33. Questions?

34. Pictures Lozeau Bridge

35. Pictures Lozeau Bridge

36. Pictures Dearborn River High Bridge

37. Pictures Dearborn River High Bridge

38. Pictures Dearborn River High Bridge

39. Pictures Dearborn River High Bridge

40. Pictures Dearborn River High Bridge

41. Pictures Dearborn River High Bridge

42. Pictures Van Buren Street Bridge

43. Pictures Van Buren Street Bridge

44. Pictures Van Buren Street Bridge

45. Pictures Van Buren Street Bridge