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V.A.O.T. Historic Bridge Committee
Poland Covered Bridge Meeting with Historic Bridge
Joe Nelson, P.O Box 267, Jericho, VT 05465-0267, firstname.lastname@example.org
- VAOT has produced a set of plans showing existing details. Preliminary plans indicating
rehabilitation work shall be finished soon. Final plans for the rehabilitation project are scheduled
for end of September 01. Another Committee meeting regarding this bridge will take place in
- D. Hoyne outlined the scope of rehabilitation work:
3 ton live load capacity per town requirements.
Restore shape to bridge -- 12" positive residual camber. 18" sag at present.
Move bridge to staging area -- not disassemble.
Overcome fit up problems to produce proper positive camber.
Warren Tripp stated three options: Shoring in place, internal supports in place, moving the
bridge to a staging area for rehabilitation and repairs. Warren also stated that the choice of option
should be left up to the contractor, not determined in advance.
- Question from DHP: Will arch restoration provide relief to overstress at end diagonals
(braces)? D. Hoyne responded yes, if the shape (camber) of the bridge is restored, the existing
end diagonals will remain in place and be ok for stress.
A further question was raised about the function of the arches: Are these really tied arches (tied
to superstructure) or do the arches develop compression against the thrust blocks?
- It was mentioned that at the last meeting in April VAOT would develop rehabilitation options
D. Hoyne stated that sawn plank floor and glulam floor systems were considered. VAOT
recommendation is to eliminate newer existing floor beams, spanning 8"--9" between existing
historic floor beams with a glulam deck. J. Weaver stated that the existing 8 x 12 historic floor
beams would not handle that span for 3 ton live load and glulam dead load. Moments would be
- Member replacement: D. Hoyne stated the following:
Bottom chord channel, rods and existing wood chords to remain in place.
A few diagonals to replace, a half dozen kingposts to replace.
At bottom splice bolted connections, restore rod holes with bushing trunnel liners.
Warren Tripp stated that it would be best to shim gaps between existing members (diagonals, etc.)
caused by re-cambering, etc., to cut down on member replacements.
Eric Gilbertson suggested profiling the channnel/rod system downward (if possible) to help
maintain positive camber.
J. Weaver pointed out that there are three systems of tension transfer at the bottom chords: The
timber notches at kingposts to chord, the scarfed joints and the rod/channel system.
- The Structures Section has not yet undertaken materials evaluation or species ID
of existing bridge members. Species ID through HTA was suggested by D. Hoyne.
- Substructure work: Concrete bathtub sections were suggested at approaches to
the bridge. Mike Fowler said that Joe Nelson had suggested stone work buildups
at a VCBS meeting last Saturday. D. Hoyne suggested laid up stone with geotextile
reinforcement (tiebacks) for the wings, concrete caps for the new bridge seats.
- Vertical profile of bridge: Will use elevations from flood insurance maps, hopefully maintain
present vertical profile elevations.
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This file posted February 13, 2002