V.A.O.T. Historic Bridge Committee
Historic Covered Bridge Committee Notes of May 6, 2002 for:|
COOLEY COVERED BRIDGE (NO. 31), PITTSFORD BHO 1443
Committee members in attendance: J. B. McCarthy, David Hoyne, Warren Tripp, Nancy
Boone, Scott Newman and Sue Scribner. John Weaver, representing the Vermont Covered
Bridge Society, was also in attendance as was Chris Slesar from the VTrans Environmental
Permitting Section, Michael Canavan from the Federal Highway Administration and Jim
O'Gorman, the Pittsford Town Manager. Alan Randall and Jay Messier from Lichtenstein
Consulting Engineers were present as well.
The purpose of this meeting was to discuss any concerns, or clarify any issues, associated
with the Preliminary Plans submittal.
Since the last meeting of the committee to discuss this project, the town has indicated that
there is a need for the bridge to be able to carry 40,000 lbs. as the town has been, and will
continue to, transport salt and sand trucks over the bridge. This led to discussion relative to the
load rating table presented on page 2 of the plans. The load rating for the floorbeams in shear is
listed as 9 ton. The consultant will investigate whether use of glu-lam can increase the load rating
sufficiently. Also, the trusses had not been analyzed by Lichtenstein Consulting Engineers due in
part to the general inherent strength of town lattice trusses as well as the relatively short span
length. The report prepared for the bridge in 1995 by McFarland Johnson, Inc., however, did
state that the truss should be able to carry 20 ton in like-new condition using a plate girder model
analysis. It was agreed that Lichtenstein Consulting Engineers would analyze the trusses in detail.
Analyzing the trusses will also help to determine how much rot can be tolerated in the truss
members. At present, it is not anticipated that any lattice members will need to be replaced.
John Weaver suggested taking some floor beam deflection measurements as well; the most
meaningful measurements would be derived after removal of the existing distribution beams.
It was requested that consideration be given to replacing bolts at their connections with the
chord with trunnels where they were trunnels originally. It is felt that this should strengthen the
connections. General agreement that trunnels should be used where we can at the bottom chord
Chris Slesar indicated that the area surrounding the bridge is very sensitive archaeologically.
He would like to see the staging for the equipment needed for the substructure work to be on the
road surface. There does not appear to be a problem with this.
Many different preservative/ fumigant/ color treatments are proposed for the structure.
The bridge is currently painted red. NOCHAR can be pigmented, but this will mostly be used
inside. There is another product, Andek, that is a fire retardant that can have color added. To
obtain a paint-like exterior appearance, the clear coat must be topped with an opaque acrylic
The preliminary plans show tongue and groove siding to replace what is presently on the
bridge. It is not felt that tongue and groove siding is the original type of siding. Different types
of siding were discussed. If planking is used, moisture content can be specified. General
agreement that tongue and groove should not be used; Scott Newman will make recommendation
on best system to use.
CONCLUSION: The consultant will re-analyze the floor system for use of
glu-lam as well as the trusses. A summary will be prepared and distributed for comment to the
committee members and others that were in attendance. Scott Newman will make a
recommendation for the type of siding to be used. The town still needs to indicate if any type of
lighting is desired on the bridge.