• Located 0.60 mi west of the village of Salisbury on the Salisbury Cornwall town line
• Bridge 8 on T.H. 1/T.H.3 over the Otter Creek
• Bridge is co-owned and maintained by the two Towns
• Bridge currently posted for 3 tons

Salisbury Station Covered Bridge: Project History

• ±154'-0" single span Plank (Town) Lattice Truss by unknown builders
• Truss patented in 1820 by Ithiel Town, an architect from New Haven, CT
• Web width of ± 5' -0" widest in Vermont
• Constructed at a royalty of $1 /foot
• Constructed to provide Cornwall with a link to railway shipping point in Salisbury

• Pier added at mid-span to level up bottom chords and remove sag. Pier designed for H10 loading.
• Abutments capped, re-pointed and/or faced and new treated shear beams placed
• Other miscellaneous timber repairs

• Significant timber repairs, including replacing and/or "sistering" all broken or rotted chord and lattice members (Spruce timbers with hardwood pins)
• Replacement of abutment bedding timbers (White Oak)
• Other miscellaneous repairs
• Repairs based on qualitative assessment
• Cost: Approx. $50,000

• 1992 - State commissions consultant study for all VT covered bridges, to include recommendations for long-term preservation
• 1995: McFarland-Johnson study completed for Station Bridge
• Fall 1998: After preliminary meetings, State receives concurrence from both Towns to proceed as recommended in consultant study
• Recommended option is to rehabilitate structure for moderate traffic
  • H10 (20,000 Ibs.) @ Inventory
  • H2O (40,000 Ibs.) @ Operating
• Complete deck and floor replacement
• Upgrade truss members where necessary
• Other miscellaneous timber repairs
• Miscellaneous substructure repairs
• New approach rail and signing
• Channel work

Salisbury Station Covered Bridge: Examples of Current Problem Areas

Salisbury Station Covered Bridge: Roofing

• Green standing seam metal roof
• New purlin boards placed where required . Existing rafters retained
• Cost: approx. $25,000

• Tie beams: Existing 6" x 8" timbers @ 10'-0" spacing
• Lateral Bracing: Existing 6" x 6" timbers in 1 0'-0" bays
• Knee Braces: Existing 2" x 6" timbers @ each tie beam

Salisbury Station Covered Bridge: Proposed Truss Repairs

• 3"x12" I.b.c, 2 }2"x11" u.b.c and I.t.c, 3"x11" u.t.c
• 3"x11" lattices
• Significant member replacement and/or sistering in 1992
• All members Spruce-Pine-Fir No.1/No.2 (assumed)

• If feasible, all replacement members will be in-kind

Salisbury Station Covered Bridge: Truss Modeling Options and Issues

• 1A: Dead load and structural capacity from original timbers only
• 1B: Dead load from 1992 timbers with no additional structural contribution
• 1C: Dead load from 1992 timbers with additional structural contribution

• Same modeling options as above

Salisbury Station Covered Bridge: Proposed Floor Replacement

• 3"x12" runner planks over 2"x 6" diagonal flooring over
• 3"x12" longitudinal deck planking
• 4"x12" transverse floor beams @ varied spacing
• 2"x 6" lateral bracing

• 6 3/4" longitudinal glulam deck panels over 1 0 1/2" x 15 1/8" transverse floorbeams spaced at 5'-3 5/16"
• Floorbeams notched to retain existing vertical clearances
• . Lag screws to stiffen floorbeams for live load deflection
• Sacrificial wearing layer "built-in" to deck thickness
• Curb placement to encourage centering of traffic and pedestrian safety
• New lateral bracing
• Southern Yellow Pine for new glulam members

Salisbury Station Covered Bridge: Project Typical Sections

Salisbury Station Covered Bridge: Miscellaneous Timber Repairs

• Replace damaged planking at portals
• Replace damaged siding
• Other miscellaneous timber repairs
• Fireproofing?

Salisbury Station Covered Bridge: Fireproofing Options

• Lighting: $6/SF
  • Place in upper rafters
  • Must be vandal resistant
• Visible alarms
  • Portal areas
• Fire detection systems: $7/SF
  • Linear heat detector wire threaded through bridge
  • Camouflage with proper coloring
• Tele-metering
  • Used with linear heat detectors, system dials fire department if there is a fire

• Intumescent paint: $6.50/SF
  • Raises flash point of timber
  • vailable in transparent finishes
  • Requires re-application every 5-10 years, especially on decks
  • Best suited, but not a 100% guarantee against fire
• Fire retardant treated timbers
  • May reduce member strength 10-20%
  • Not logical unless treat entire bridge

• Hydrants
  • Recommended at both ends of bridge
  • Pressurized: $3500 ea.
    • Need connected water source
    • Usually not practical at CB locations
  • Dry: $2500 ea.
    • Uses water source on site
    • Maximum draw height approx. 30 ft.
• Sprinkler System: $10.50/SF
  • Placed in roofing
  • Water drawn through dry hydrant
  • Open head system - no water in it because would freeze in winter

• Depending on measures taken, may range from 3-15% of total project costs
• Reduction in insurance premiums
• Do nothing is an option!

Salisbury Station Covered Bridge: Proposed Substructure Repairs

• Existing laid-up stone
• Faced and top leveled in 1969 rehab.

• Existing laid-up stone
• Wingwalls faced and top leveled in 1969 rehab.
• Re-point/face remaining exposed masonry

• Existing bent-type pier: Concrete cap on single row of vertical steel piles constructed new in 1969

Salisbury Station Covered Bridge: Proposed Approach Improvements

• Currently no rail on either approach
• Qption 1: Steel backed timber rail
• Qption 2: Heavy-duty steel beam weathering (or galvanized) rail on timber (or steel) posts with timber offset blocks
  • Both are crash tested, standard rail systems
  • Construct wingwall extensions for shoulder housing
  • Optional rail connection to bridge portal timbers

• New pavement on both approaches
• Narrow bridge and clearance signing
• Other miscellaneous drive and grading improvements
• Stone fill for bank stabilization

Salisbury Station Covered Bridge: Proposed Channel Work

• Remove debris at upstream side of pier
• Stone fill for bank stabilization

Salisbury Station Covered Bridge: Plan and Elevation


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