Present at Meeting:
Steve Hodgdon had another PowerPoint Presentation on the substructure. Currently there are large voids, evidence of settlement, the caps are only partially supported and there is evidence that there is some tilting and/or sliding of the abutments. Over the years, the grade has been raised 3-4 feet which has added stress to the substructure.
Many of the same "pros and cons" as were discussed at the previous meeting were discussed again. However, using figures provided by the stone mason and using more accurate quantity estimates, the consultant now estimates that a stone abutment would cost $200,000 - $250,000 more than a concrete abutment. The consultant recommended use of concrete, primarily on the basis of cost savings and that it would be easier to install at the tight site that is present. Use of a stained dry stack form liner was recommended.
To expand on the "tight site" discussion, the consultant has determined that concrete abutments would have a smaller footprint and could accommodate approach rails on the wings. Further, the wings can be built to "fly" off the main stem wall with a single footing. Concrete would also provide for the greatest hydraulic opening. The bend of the river does provide some physical constraints on one side of the bridge; installation of a temporary bridge provides physical constraints on the other side.
The stone mason recommends use of much larger blocks of stone -- about 2' x 4' at the bottom courses, extending at least as far into the abutment. Therefore, the appearance of a new laid-up stone abutment would be very different from the existing abutments. Further it is proposed that the footings and cap would be of concrete regardless of what the remainder of the material used will be.
Lively discussion followed. Some basic points brought up include: the bridge has a concrete deck and steel beams, a new stone abutment would be very different in appearance both in its size and the stone used, there will be a fair amount of concrete used either way as it is proposed that the footings and caps be of concrete, form liners are not desired, no old fabric would be saved if new stone abutments are built, the cost differential is fairly significant. Some discussion followed as to whether to include bid alternates to see how much more stone abutments would cost.
The following motion was made (with some reluctance): "Motion to replace laid-up stone abutments with colored concrete with chamfered edges. Basis for motion is that there is going to be a large amount of concrete for the footings and caps. Rather than a reconstruction, a new stone abutment would be a change in stone type and size. Also, the site conditions favor the use of concrete.
Committee members and the Town voted. All committee members voted in favor of the motion. The Town representative voted against motion -- stating that he would like to see stone used and include bid alternatives in the Invitation for Bids. The Vermont Covered Bridge Society representative stated that they would like to see new stone abutments built. Motion to replace stone abutments with concrete had the majority of votes (7 versus 1).
The committee would like to thank the consultant, VHB, for their thorough presentations. As well, we would like to thank the Town of Randolph for sending a representative.
Chair, Historic Covered Bridge Committee
[This article was originally posted May 12, 2006]