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The Vermont Covered Bridge Society Preservation Committee Conference

Meeting Minutes (edited - full text available on tape)

Date:
January 20, 2001
Time:
1:00 P.M.
Place:
Neighborhood Connections Building Brandon, Vt.
Attendee participants:
Ed Barna, Neil Daniels, Jan Lewandoski, Irene O'Dell, Phil Pierce, Doug Porter, John Weaver, David Wright
Moderator:
Joe Nelson
Recording Secretary:
Ruth Nelson
Guest:
Richard Baker of Neighborhood Connections Building Brandon, Vt.

David Wright:

Probably the first thing I should say is I'm David Wright, President of the Society for the Preservation of Covered Bridges, and as you can imagine on the subject of covered bridge preservation I have quite a bit to say, but I'll try to compress it as much as possible. Probably the first thing to do is to go over the "talking page, or target, you so kindly drew up, and give you my reactions to it.

Anyhow, I had the same reaction as you did to a certain verb [lays, lies] in the first sentence in paragraph number one, which I fixed. I certainly approve of that statement as far as it goes. I would say that one could make it a little sharper so that one has a better idea, really of what we are talking about. The first thing that we talk about covered bridge preservation, well what is it we're trying to preserve, and it is the what of the thing that is often the problem. You hear covered bridges being spoken about as if they are ideas, notions or concepts, some sort of mental things and of course there is thought that goes into designing one, thought that goes into building one, and certainly there is thought that goes into trying to understand one that's been built one hundred years ago.

But a covered bridge itself is something else, and I've used this sentence a few times myself, I think it's a good one, a covered bridge, it's stuff, it's particular materials arranged in a particular fashion by a particular person for a particular purpose at a particular time.

That's another way of speaking, in part, about historic fabric, which is certainly at the heart of what we are trying to do when we preserve a covered bridge. A replica is not an original. Even if you have to repair a covered bridge in kind, which of course often happens because of the conditions they get into. It's the most sensitive kind of restoration or rehabilitation that you can have. But it is still not the original structure. Anyhow, I will come back to that notion probably again.

Paragraph two; I would suggest historical, rather than historic. Those two words are like effect and affect. The way it is written here is; "To preserve historic integrity when a covered bridge is repaired," I would change that to historical; figure the difference between an historic society and an historical society. Something that is historic is of history, usually history of a certain time past, where something is historical pertains thereto. Anyhow, that's a suggestion, rewording.

The question about the timber species, I would say, let me read it the way I reworded it to preserve the historical integrity when a covered bridge is repaired, the joinery used by the original craftsman, you had 'should', I would say 'must', must be duplicated and the timber used in the repair should be of the same species as the original. And it goes on; "native timber should be used in covered bridge restoration, other timber to be used as last resort."

Well certainly that would be ideal, but there is a problem sometimes of being able to find the same quality original timber, for instance if you are dealing with first growth spruce, that's wonderful stuff, fine grain and so on and so forth, you can, it's true, find sticks that are of that quality, but it's hard to do. And you have to know what you are doing, and usually the general contractor is the fellow that gets a lot of these jobs doesn't, or doesn't care, or hasn't put enough money in the budget to be able to do it.

I'm all in favor of the original species of the quality and the kind if you can find it. If you can find it, it certainly should be in the contract.

Another comment on that; If you go to a different species, sometimes without making a great change in the disposition of the truss you can get quite a bit greater carrying capacity. So that's an idea, rather than resorting to other things one might do, sometimes just changing one or two sticks to a different species will help a great deal with whatever the problem is in the bridge.

Number [3a)]; "Trusses must be kept dry . . ." I certainly agree with number {3a)], the only thing I would change, I would change "the approaches to the bridge must be properly drained." I would say 'sloped'. The reason I suggest that is because I've seen any number of devices that have been designed at the mouths of a covered bridge the idea for them to keep water from flowing into the bridge. Usually what happens is they are neglected and they get full of sand and gravel and of course they are not cleaned out when they should be. If the slope were right, it wouldn't make any difference, you wouldn't need the device and the water wouldn't run in there anyhow.

So it seems to me that the simple elegant solution, where possible, would be to have the roadway slope away from the bridge.

Number [3b)]:"oversize and over weight vehicles must be prevented from entering the bridge. A smooth transition between the approach roadway and the bridge . . ." I would change deck to floor. Covered bridges, properly speaking have floors in them, not decks. A deck, except in a ship, implies there is no roof over it. In any case, it's a minor point. The "'floor' must be maintained to prevent shock to the bridge structure by entering vehicles."

Well, there are a couple of ideas in here. I think the oversized vehicle is a simple problem. You can devise telltales that limit the height or the width, whatever you want to do with any prospective vehicle. It's like a kind of a goalpost a fellow has to be able to pass through first before he can pass through the bridge. The problem is sometimes there isn't enough room to set the telltale far enough back from the bridge so it doesn't spoil the bridge pictorially. They are not very pretty objects if you have them standing right next to the bridge. It's aesthetically displeasing. I would personally would live with a little bad aesthetics if it saved the wind braces and sometimes the cross ties in the bridge from being knocked out by an over-height vehicle. The oversize is the simpler of the two problems. The overweight, I don't know. To some extent if you can control the size of the vehicle that's entering, you control some of the weight, but that doesn't always follow. A flat bed truck can have a low profile and can weigh a hell of a lot.

"Preventing the shock . . ." That's a technical thing. You can usually do that by supporting one or two of the first floor joists somewhere in the center if the abutment is wide enough to permit that. That stops that impact when the truck drives onto it. It's a simple thing to do if you can do it and the bridge abutment is such to permit it, it's very much worthwhile doing. The vibrating load that's what happens in bridges, to the extent that these can be damped out, it's very good.

[3c)]. It reads: "In addition to regular maintenance, the bridge should be inspected twice annually . . ." I certainly agree with that. "Once prior to spring, once prior to winter with remedial action taken in preparation for the season." I would say late in spring and the reason I say late in spring would be because it's certainly during the winter where the most amount of sand and gravel and God only knows what else is liable to be collecting in these structures. The time to take it out is theoretically after the last snow fall and the last sand truck has done the roads. So you remove in most cases the source of the sand; if the bridge is on a dirt road, it's another matter, let's say it isn't. It would be a good idea to get it out of there because the sand and other debris retains moisture you don't need in a bridge, particularly the parts where the framing occurs, so the ideal time to remove it is after the last amount has been put in and before the temperatures get too high so this moisture can really do a lot of damage to the wood.

The other thing I would say, it's a lot better to blow out a covered bridge with compressed air than it is to wash it out with a fire hose. You have a roof on it and side boarding, why? To keep the water out, so why do you want to bring the fire hose in and put a whole lot of it in place, and drive some of the stuff you are trying to get out into places, you make it wet so it's goo, mud, you can drive it into places where it might not otherwise get, because it's a slurry when it's gone in there, it's liable to stay, whereas compressed air does a lot better job of removing it.

[4], let's see. I would comment that, here of. Course, I'm touching on controversy and contention. But I think it is a very rare case when a covered bridge, even one that is very badly deteriorated cannot be restored somehow. It may mean a lot of replacement material, it may mean a lot of splicing, it may mean a lot of doubling up, but remember what we're trying to save, we're trying to save the fabric of the old bridge, the historic fabric. So the splicing, the doubling up does that and at the same time depending upon what we're talking about. At the same time it permits the historic fabric to remain in place, which is, after all, what we are trying to keep.

[4a)]. Here again, we're talking about retired bridges. "The bridge retired on site can be repaired to safely support foot or cycle traffic while maintaining its historical integrity." That's true, of course, but the problem is bypassed bridges can turn into abandoned bridges. We all know how tight public moneys are, when such a bypassed bridge or preserved bridge is in the charge of the local town, or even if it is a charge of the state highway department, it's a lot easier to justify funds for something that is serving for an obvious public good getting fellows from one side of the river to the other than it is to save something that is on display. So that's a problem. I'd much rather see a bridge bypassed and put in reserve somewhere than I would see it demolished, but it doesn't mean that because you bypassed it and put it into a park that it's safe.

I have a comment about [4a)], [4b)] and [4c)]. You could read them as an encouragement for these bridges to be either bypassed, or disassembled and moved somewhere else, or simply moved somewhere else to get them out of the way for a new bridge or for a replica and not making the town or the Agency of Transportation jump through the hoop of trying to save the old bridge, keeping it in service, functioning as it was originally intended.

Number [5] in a way refers back to number one, and all of it is correct here, I agree one hundred percent.

Number [5a)], there's no question about non-destructive test protocols must be developed. One of the problems we have with a lot of covered bridge restoration projects, and I'm not talking about you Jan when I'm saying this, but the folks who end up doing them are general contractors, I'm not shooting at you either Neil, so don't feel wounded. They are good fellows, but they do the work they know how to do. And covered bridge repair, covered bridge restoration, seasoning, if need be of timbers, selecting timbers, finding where to order the odd ball stick is not something that is usually in their kit. So you see very often winning the bidding process, and then come the change orders' we can't find this material, it isn't obtainable, wouldn't it be better if we did this project a little different than it is on the drawing, and so on and so forth. So, consequently projects get out of control and bridges end up being very seriously adulterated, they can even disappear. That is not desirable for most people's point of view in this room.

Now in terms of general preservation philosophy. Certainly we in the national society favor doing things in the traditional manner. We're not friends of glulam, we're not friends of other more modern materials, like plastic, I'm sure there will be proposals to incorporate them in bridges. If a bridge truss has to be strengthened, as sometimes a it does, we don't favor a redesign of a truss if it can possibly be avoided, because after all that's what we are trying to save. Remember that's the monument, really, the shed isn't. Everybody thinks of the covered bridge as being the appearance of it, and of course one understands why, it's often very beautiful, the setting is beautiful, the stone abutments are beautiful, the aged wood of the side boarding, and if the bridge still has a wooden roof, that's very beautiful, but the real monument is the trusses, upper and lower lateral bracing systems and probably the wind bracing. So anything which alters those makes the bridge less bear witness to it's period.

I've probably used my ten minutes up, but I'll pass this out to you now. [A draft of a bill proposed by Rep. Don Davis of Cavendish in 1989: "An Act Relating to The Restoration And Preservation of Covered Wooden Bridges."] I'm not going to read it to you but about 12 years ago, as a result mainly of the argument over how the Cornish-Windsor covered bridge should be restored. I don't have any quarrel over your joinery, I've always praised your joinery, Jan, but the legislator and myself and various other people in New Hampshire who had fought for a traditional restoration of that bridge decided it was time to enact into law some preservation standards in New Hampshire. We came very close to doing it. We ultimately failed to do it primarily through opposition of the Department of Transportation. But we came very close. At the same time there was a Vermont legislator, Don Davis who had heard about the thing somehow. He got a copy of the New Hampshire draft, he told me he would like to put this into Vermont, do you have any problem, I said absolutely none. He took my copy, every legislature has people who draft bills for legislators, so he had that much done and sent it back to me and I made some minor changes in the wording, not anything else. And for some reason we ended up pulling the bill, I think probably because of opposition but the thought of trying to work in two states at once. [Copy of bill appended]. You'll see that it is in favor of traditional restoration and using traditional methods to restore. And that really sums up my position and sums up the direction of the National Society.

Jan Lewandoski:

I thought David had a lot of excellent points. I'm really not in disagreement with anything. I'll go through some of the things I've noted on the document here though.

Paragraph 1. In my own feelings an opinion about it, the design and the historic engineering of the bridge is as important as the actual structure, however, I wouldn't put that in here, because it leads people to very easily say, "well, we'll destroy the whole bridge but we'll build it back like it was." So, I'd leave it out. Personally, I happen to think, when (I look at a bridge, I like the workmanship and the patina, but I see that all the time in barns, church steeples and everything else, it's the historic trusses that are so interesting. I think it is the most important thing we are trying to keep together, although, and there is one thing about it, emphasizing it is good though, rather than subdivide a bridge into several spans, just to keep the material intact, I'd love to see the bridge still doing what it was supposed to do initially. That's why, actually, I'd vote to change more material, if I had to, to keep the bridge as a single span still functioning, rather than save material but reduce the function of the bridge. I guess I have two minds on that one right there. I indeed, don't want to invite people to destroy bridges wholesale and make reproductions of them. But I do like the engineering as much as anything else, I think it's very important, so we should emphasis it somewhere.

The question of preferred methods. Question how to repair covered bridges, a gigantic topic and not amenable to simple solution. I just had an article published in an ASTM book on wood structures. I actually went to the Stannard town hall today to make copies of it and it jammed up in the copy machine and I stopped doing it, didn't get it done. What it dealt with was restoration strategies.

If you can, restore in kind, same species, same joinery, same member sizes, same everything. But there are often reasons why you can't, legitimate reasons, one of them being the changing use of the bridge. If you are going to put much heavier loads on it, you may have to beef it up. Most of the bridges in the state had lighter floor systems at one time, for horses and wagons, and heavier trucks required heavier floor systems, and throughout the 30s, 40s, and 50s, you see these gigantic, frequently Douglass fir floor systems, or the spacing of more joists between the joists and things like that. You may have to do that.

Another problem, and this is one I run into a lot. I know a lot of people who are romantic about covered bridges, which I am too, hate to admit some bridges were no good the day they were built. They are still here, but they are bad, they have flaws in their design. The Pulp Mill in Middlebury is a classic example. It was originally a single span of 180 feet. They sent someone to Essex to look at a bridge, I believe it was Essex, Vermont. I believe he looked at a John Johnson bridge, [built] about 1810. A great bridge. The person misunderstood, made huge errors in the construction of the Pulp Mill, resulting in the 1860s, I think the Pulp Mill was built in the 50s, not the 20s, by the way, the addition of arches. Not long after that the arches failed, the arches that are there now are not those [original] arches. But the arches have always failed in there, except the tall central one, and the subdivision of the bridge into groups.

Salisbury-Cornwall, inadequate probably the day it was built, Cornish Windsor, getting itself in trouble the day it was built. So, these things do happen. Consequently, in effect, the point David made, so what do you do? Through the bridge away? No. Stick piers all over the place in it? Well, maybe, but you can't easily do that. In the Pulp Mill, it required reversing half the bracing when you put piers in. Salisbury-Cornwall, lattice trusses you can subdivide if you want to. You can do a number of other things.

I have an article that does it, list a whole list of things in order of preference from the least interventionist. Repair in kind same species, joinery, size, Stepping down to change of species of some members.

In Waitsfield, the Village Bridge, 1832, an excellent bridge by the way. One hundred and eighteen feet in a single span. When sidewalks were put in and bed repairs were done, the check braces were taken out behind the first posts. They are very heavily loaded, the posts bent. I shifted the posts over from spruce to white oak, just the first posts, I put check braces back in again. Check braces alone might have done it. But I think they also pretty heavily loaded anyhow. The posts there were no bigger than the posts out in the bridge elsewhere, whereas in really good bridges of big size, like Blenheim or the Shoreham Railway Bridge for instance, the first posts deflect their loading by being bigger at the right points. So that's one thing you can do. I don't really have time to go through this all right now, but there is a whole list of steps you can take. We don't want to list them in preference. If you can leave it like this, do it. If that's not enough, here is the minimum, next minimum step you can do, if that's not enough, go to the next one, and so forth. But anyhow, it's not a simple question that we just fix them all the way they were built because some of them were getting in trouble the day they were built.

This doesn't only go for bridges, it goes for a certain percent of the churches around here, the trusses failed. They don't fall in on the people right away, but anyhow, that's one point I want to make.

Another point about use of native species, which I sort of specialize in. I go out into the countryside looking for big trees. And I extract them, and I've had quite a lot of luck. I put two sixty-foot twelve-by-twelves of spruce in the Warren Bridge which made seamless one piece bottom chords. Very hard to come by. If someone showed me a project on fairly short notice and needed a lot of stuff that size, I just can't get it. Your going to have to get something else. That's one thing.

The other thing is, a lot of early bridges had a lot of white pine in them. But you can't get white pine of that quality anymore. It was tightly grown, relatively free of knots, straight grained. John Johnson again. One lumber list for a bridge he built in St. John Quebec, in I think 1815, started off he wanted two hundred and fifty-four fifty-six foot eighteen-by-eighteen white pine. Well, they were available. You might be able to get that, but they won't be very good pieces of white pine. Big knots starting in about thirty feet probably. So, sometimes you have to shift species because you can't get stuff of equivalent size.

Taftsville. Beautiful bridge. Over by Quechee. The posts are chestnut. You are not going to get them. But you can shift to oak and you haven't gone very far. Its stronger. So, don't get locked into a position that's going to cause you to be at war with well intentioned people who actually know what they are doing, and know that they can't do what we're hoping they can do.

Ideally, yes, we'll match those species, but for some its hard to do. The biggest problem with species though is the engineering drawings. I don't want to fault anyone who is here, because I know, we all have those problems. Many engineers in knee jerk fashion specify Douglass Fir and southern yellow pine. For everything. It's easy to get, it comes graded, comes in big pieces and it's got high design values. And so consequently we're frequently shown plans where that's what is called for.

Frequently the contractor isn't in at the beginning of the process. He's late in the process. He's told to get the contract and start working in thirty to sixty days. They've been planning the bridge for two years. That's why it'd be good to get in at an earlier date. And not ask the contractor why he didn't start fighting what the state of New Hampshire, Massachusetts or Vermont at that point in time.

Although I do want to exempt Vermont from a lot of criticism. The State of Vermont, the AOT, most of the bridge jobs I've done have been repair-in-kind jobs. With no engineer specifications. Most of them. Or if there was an engineer looking at it, they looked at it qualitatively. They said "huh! That's having trouble, that isn't! That's not having any trouble, I'm not doing anything else." My point is that frequently the specifications come specifying certain species. The contractor hasn't got much control over it The question is to get in early on the plans.

I'll get into a whole 'nother topic now. I've been working for the last two years on a project having to do with Chinese houses. You say it's not related to bridges. But it has one very different relationship: It's private, there's an almost unlimited amount of money associated with it. It's public building eventually. Anytime the engineers come up with something that we don't like, where it compromises a certain member, we have the money to do what we need to do about it. We keep going back and if we still don't like the results, we then take wood samples and send them Blacksburg Virginia and get tests done. If we still don't like the results we then do actual load testing of members. And see whether they're worth what the engineers want them to be worth. How they approach the predicted values. Very expensive, very time consuming. It gets around the problem of design values which are in my opinion, too conservative. Once again, the problem with using native timber and the problem with a lot of joinery. I know there has been a lot of controversy in the state, the question of what size, what species, what joinery can be used, and I guess I'd argue for, it's a big change in some ways.

Not doing Quantitative analysis of bridge trusses unless there is evidence of failure that's not caused by rot. Unless there is actual evidence of structural failure in the original material of the bridge, not in the deteriorated material of the bridge. As soon as you go to quantitative analysis, you go to design values, which are extremely conservative, are not sub-species specific. They are very general. That's why live oak has very low values although it's a very strong wood. Because the white oak group has forty members. Some of them are weak, and it is not that in the bulk of timber. No one could identify what it is, whether it is some horrible piece of white oak from Oklahoma or whether it's Quercus Alba. Argue for not doing quantitative analysis. To me, it's probably the most important issue. Try to avoid quantitative analysis of these bridges, do qualitative analysis.

The whole question of glue laminated lumber, also which I don't think is needed. I think it has high design values, but its no stronger than anything else. You may have more confidence in it. It comes in longer pieces. I'm sure that's why it was used in Delaware County [allusion to the Hamden Bridge project], it comes in such long pieces.

Testing wood species? Native species? I don't think you'd get values different that what you get right now. There is a difference between strength wood tables and design values. If you go to strength of wood tables, which are different, does everyone understand that design values is not the same as strength of wood? That some woods are very strong but have low design values? Some woods are weaker and have high design values? Design values are designed to avoid a set of plans producing a situation where someone shows up with a piece of wood and says this is white oak, or this is spruce or this is something and its really a lousy piece of wood, The design values take you right down to the absolute bottom, you could probably be at in any group of trees.

They are one thing when you are ordering new timber. They are another thing when you are analyzing existing timber on a bridge. In Dummerston for instance, the engineers from Boston decided to treat the lumber as all number two. Only because they couldn't see all four sides of the piece. It's a standard engineering thing. It reduced the values by about fifty percent. These are complicated engineering issues. I don't know if we can deal with them here. But when we talk about testing, I think we get roughly the same results. The problem is the design values themselves are too conservative. By the time you get done testing wood, going through all the reductions to produce design values, you will get lower values, and by the time the engineers get through making calculations, they'll find the pieces are inadequate. Frequently. I guess the only thing I'm recommending is to attempt to only fix things that are broken on covered bridges. Not fix everything else.

Lewandoski:

That's what I'm trying to avoid because I deal with these issues all the time, and they have good intentions toward these bridges too, but their analysis will lead them to demand things that we frequently are sure that the bridges don't need.

Doug Porter:

My name is Doug Porter. I've enjoyed the comments of David and Jan, and have very little to add, except to say that I agree that our statement the way that it stands now feels a little heavily weighted to the fabric side of things. And that some of the interventions that it discusses in an effort to save fabric potentially makes attractions in the design column as a result. So that I think a discussion of designer of the historic relationship between the parts in an effort to arrive at an understanding of what kind of value we want to place on original design in planning repairs with perhaps the goal of drafting a paragraph that would address that for our statement would be a good and interesting thing to do.

Joe Nelson:

What we'll do then is transcribe these [proceedings] and then circulate the minutes among ourselves for further comment. We'll carry this on, if you like, and create a document out of this.

Phil Pierce:

One of the things I would like to ask us to consider. I've done a little bit of detective work but not near as much as I want. If we were talking about naval architecture, the concept, I believe is common that fabric be damned. As long as you keep the keel. As long as you maintain the integrity of the structure. From my standpoint, and I don't profess to have been involved with covered bridges as long as many of you in this room, but I have been involved for eight years, and I've sensed that as soon as a bridge is bypassed, taken out of service, its going to lose the probability of funding, in time it's going to fall in the water. I don't think that's what the original builder of that bridge intended to happen. I think our mission, from my standpoint, should be to keep that a functioning bridge to serve its public.

I agree whole-heartedly that the bridges were not designed for the heavy kinds of vehicles we ask them to handle today. And as one of the two engineers in this room challenged with putting our professional engineering licensure on the line, subjecting ourselves to the risk of professional attack should we choose to give up on public safety, is an awesome responsibility that I don't sleep well with at night. If I could offer some nudge in the ribs about how I'd like this group to proceed, I'd rather have the group push for less design weight vehicles, instead of insisting on a twenty ton truck, which has been my challenge in a few instances, even a fifteen ton truck, I'd rather see these bridges open for automobile traffic. Which we could, I'm not sure that any of us could devise a headache bar to insist on only low height vehicles, but I don't believe that we will ever find a commitment of our society to limit themselves without such an issue, so I guess I view some kind of height restriction as a necessity in order to insist on lower weight vehicles. I'd like us to go that way.

To get back to the concept of fabric, I guess my instinct is influenced heavily by comments I've heard from a state preservation officer, from one of our sister states that felt, that perhaps it was as important, if not more important to maintain the skills of dealing with a bridge effectively by craftsmen that know what they are doing, rather than necessarily saying that thou shalt keep the fabric at all costs. So, I'd maintained in my professional involvement with these bridges, looking out for public safety that I'm willing to give up fabric if I have to. To be able to maintain a sense of using the same kind of approach if I can without having to resort to the use of steel or glulam. All of you in this room recognize that my P.E. stamp have been on plans that have used a lot of glulam, and again, *I've been forced into doing that because I've been forced into dealing with heavyweight vehicles.

Jan touched on something I'd like us also to consider pushing hard on; the tradition of bridge construction by what is my feel termed a design-bid-build situation. The designer prepares a set of plans, a contractor then bids on those plans, and builds in accordance with the plans by the engineer, and they are not really working as a team at all. The engineer is working in a vacuum. Often times today, the person doing the engineering may have relatively little experience with covered bridges. I think we have an opportunity in this kind of document to push the owners of covered bridges and the people providing funding for covered bridges to strongly consider a design-build type contract, where whoever was going to be the lead, which traditionally, in the bridge field would be the contractor, then finds himself an engineer who he is comfortable with, that is skilled enough to do the work, and then work together as a team.

An aside as an example. I worked for Neil on the work that was done on the Mill Bridge in Tunbridge. I'm the son-of-gun that had to resort to a different species. My challenge on behalf of Neil was to build it out of eastern hemlock. Well, that's fine, But I was challenged to have a capacity, as I recall, of fifteen tons and I defy any engineer to be able to come up with eastern hemlock that will satisfy the loads of fifteen tons with the sizes of materials we were trying to use. It couldn't be done. I tried real hard. So I resorted to a different species. But even then, the floor beams are much heavier. Because the loads are heavier. We had a very simple little detour on that bridge, and had the community been willing to tolerate three ton capacity, the floor beams would have been substantially smaller.

So I'd just like us to perhaps recognize more than we currently recognize in this document, that those of us that are challenged with putting our neck on the line professionally, I can lose my license if I decide to ignore quantitative evaluation of bridges. I choose not to do that, and if we push the engineer out of this process by constructing a document that in essence that makes it impossible to do the engineering, then I don't think we're doing anybody a good service.

So I'm just trying to offer, in a pretty forceful way, another set of issues here, that I think are equally important. From my standpoint, fabric is nice, but the skills to do it, I want my grandkids to be able to do it. If we don't do the work on the bridges, we abandon them, and make them museum pieces, if Jan goes out of business and dies, and Neil goes out of business and dies, and someday there isn't going to be anybody that knows how to do this. As long as we continue to do the work on the bridges, people like us are going tomaintain the skills, hopefully there will be an engineer or two that can play along in the game and understand how to take advantage of things.

Ed Barna:

Well following up on what [Phil] has just said was very educational...[did not pause while tape being changed]...from a tourist's point of view, coming onto a bridge and seeing one of these projects where you can see some the timbers are new and some of them are old, that has its own fascination, but I think that, at the same time I feel that it is important to preserve the original timbers as much as possible. I think maybe what the policy ought to do is say, if they can't be preserved in the bridge, they ought to be preserved, or reused in some way out of the bridge to maintain a kind of chain of evidence of the construction, and also, to leave something to the future. In the field of archaeology, typically on a site that's being investigated there will be something they leave undone, because you don't know what tools will be available to future archaeologists and they can't presume to say they can learn everything that there is to learn from that site at that moment in time, and I think that's true with the timbers as well.

I know it's schizophrenic going in both directions, but I think one of the greatest pieces of official vandalism that's done is the way the old timbers are just tossed away when even if they weren't put in the local museum or some other museum, there are various crafts people who could do things with them. To put them in a pile next to the salt shed and let the rain pour down on them seems like a terrible waste.

Going back to number one, "The value of an historic covered bridge consists in the workmanship, joinery..." But I would add here, I said this in one e-mail, I think to you, Joe, that I think also, in the role that the bridge has played in the life of the community and in the lives of the individuals who have used it, because they in many cases have been very important to letting our towns function as towns, letting our farms function as farms even, and that I think is part of the historical record.

On the historic, historical in paragraph two, I would actually stick with 'historic integrity' just as a phrase which would be consistent throughout. I can understand the point that's being made but I think in this case 'historic integrity', integrity is what's historic about it. The phrase exists as a phrase and you can't really separate out the one word from the other. I think it's an acceptable phrase as is.

Maintenance of covered bridges; John [Weaver] had said add something about fire retardants and fire protected systems, I agree. I happened to encounter No Char Fire Preventer some years ago and it has now become used more widely in Vermont, it's been used on quite a few bridges elsewhere. That stuff is kind of amazing. The company at one point was wondering if I could act as some kind of agent for it, and sent me a video tape where somebody had used this thing in a barn and there was a paint factory in the barn on the first floor. The barn had been hit by lightning, the recipe for total conflagration. The paint factory burned, the second floor of the barn didn't look like there had been a fire at all. In another part of the video, they had this thing in foam form that a fire department could spray onto a fire. They had a two storey, some kind of garage going, fully involved in flames, flames coming from every window, every doorway, the firemen arrive on the scene, what good can they possibly do? In one minute it's out! Stone cold out! Science has come up with some wonderful things, and I think we have to recognize that it can be an ally of the covered bridges.

And that leads to the issue of traffic capacity and having them exist as bridges that are used. I tend toward saving bridges by building bridges near them if they are going to be massively overhauled, you know, the twenty ton business, I would like to see, like in the case of Sanderson, an additional bridge built. In my experience, having a bridge in use as a bridge carrying traffic does not save it from fire and vandalism. The Dean bridge in Brandon was certainly in use, The Orne bridge in Irasburg, and on the other hand there are some very remote bridges you'd think would have been torched long ago, the creamery bridge up in Montgomery I worry about. I think that what it comes down to is, sooner or later the society is going to have to recognize that walking and cycling are transportation too. Our over-reliance on the automobile is a historic preservation problem in all our downtown streetscapes, and it's a problem in terms of the environment, and to assume that public transportation use is equivalent to the internal combustion engine type of vehicle that is so common now, I think will be a little short sighted. However, I wouldn't object at all if in the policy which would advise against methods of historic preservation which isolate bridges and marginalize them from community use, because I would agree that is a danger as I say, how the Creamery Bridge survives near that nude swimming hole, I do not know.

I'm very grateful for everything that has been said about the difficulty of using native species. I would agree with [Phil} that maintaining the bridge skills is more important than maintaining the exact species of timbers, but it doesn't hurt to try. I don't know wether it's anything that should be in a Vermont Covered Bridge policy, but I would hope to see eventually plots of timber grown for the express purpose of creating and restoring wooden bridges. Those plots would take a long time to mature, grow them pretty much in the old growth fashion, but I'm just not sure how that can reasonably be done, so I'm certainly not advocating that it be put in the policy, just sort of throwing the thought out.

The vehicle weight restrictions. I saw my first height clearance structure in Pennsylvania last summer, and I'm willing to compromise having them a certain distance from the bridge to keep things which are too large from going over. It would be interesting to look into whether there is some way to create something which is a breakaway structure so that if an emergency vehicle absolutely needed to pass it, that it could. Thinking particularly of fire engines here, I'm not sure what their clearance is, but sometimes they need to get somewhere fast. As John has pointed out the ability of these bridges to shift their loads, something that is going over on a one-time basis and to gradually come back means that they can occasionally take a much higher load than they are posted for.

One other thing about preserving covered bridges as secondary structures rather than primary transportation structures. I think it also gives you the chance to preserve a crossing. If something is constantly needs to be updated to meet modern transportation system, it needs this kind of guard rail and it needs that kind of pavement and that kind of shoulders, the entire approach to the bridge changes, and if something is not going to have that kind of intensive use, you could go back to something that looks like the horse and buggy days, roads going to and from it. And I think from a tourist point of view, that could be very charming. I don't think much attention has been paid sometimes to the neighborhood of the bridges, I know that for instance in farm preservation, the people who care a lot about barns say, well, what we really want to see is the barn plus all the out buildings. And I think, to a certain extent, especially if you are taking pictures, if you have a bridge and its setting is magnificent as well, then you have the kind of bridge people are going to sit down and paint, or take pictures of or buy postcards of or whatever.

Neil Daniels:

Neil Daniels from Weathersfield. I would like to address the Federal Law and urge us to have a paragraph in our Preservation Policy that responds to the federal law, since that's appropriate, that's where some of the money may come from.

The federal law is silent on weight limits, but it does say that the money is only available as a grant if its carried out in a most historically appropriate manner and preserves existing structure of the historic covered bridge and the project provides for the replacement of wooden components with wooden components unless the use of wood is [found to be] impractical.

That's the kind of thing I think we should address because the federal law that's enabling legislation for funding is real. The other thing is, we should, and I'd really rather talk about this after John [Weaver] because he's the Bridge Watch man. I think we should tie in this policy the Bridge Watch to the inspection and if we are talking about two inspections a year in the Bridge Watch and then we should tie that in to the every two years, Federally mandated state inspection which carries with it some teeth. The bridge watch inspections probably don't have much, but our Bridge Watch people should be able to work with somehow, with the state inspections to see that things get done.

The only way you are going to keep maintaining these bridges, even after we build them is to keep the maintenance up, and the towns are pathetic in their ability to neglect all the road structures. They'll paint the damn plows twice a year, and the sanders and the bodies, but they won't maintain the bridges. That's psychologically true. We need to address that, and then see if, going forward we couldn't make a change in this.

On weight, I want to speak a bit about that. I own a crane which is 110 thousand pounds. And I can move it throughout Vermont, and do. It required permits and can only go certain places. They are not building bridges for those, but other bridges have been built for those. That's 110,000 pounds. A typical log truck is in excess of 80,000. We're really discussing what Phil was saying. Thirty thousand pounds is a loaded school bus, a loaded oil truck, a loaded milk truck, a loaded town truck. Any of these things can be more than that, but that's in the realm. Certainly we shouldn't be building for anything more than 15 tons or 30,000 pounds.

But I absolutely agree with Phil that we should be closer to passenger car use with these structures because that's closer to the weights they were built for initially, but many of the old ones without any work on them will carry 30,000. They won't calculate, but they'll carry it day after day. That's some of that "Excess Carrying Capacity".

John Weaver:

I've already commented on quite a few of these items, so I'll confine my comments to the comments so far.

think the answer to covered bridge evaluation is better quantitative analysis. This may involve some evaluation of secondary support members and reserve capacity of the bridge as well for live loads. It certainly involves some investigation and evaluation for dead load which is long term and can be more severe in some cases than live loads in some structures. To enhance the quantitative analysis I think that when a project is started, if possible, a wood scientist should be employed to give an evaluation of just what the lumber you have there in the bridge is so you know what your starting point is, so you don't just run, well, like most engineers, to the NDS tables and look for the most conservative values to work with. If you know what values you really had to begin with, then you know where to start.

The other point I wish to make is regarding abutments, piers and other structures. We don't really talk much about this, but I think we ought to develop a policy towards rehabilitation, maintenance and reconstruction of these units. And I'll tell you why. Sometimes that's all you have to go with, like the bridge is burned down or it's been destroyed for some other reason, then the only thing that still qualifies that bridge for rehabilitation are the substructure units that are left. That's your ticket to getting your five percent local participation for the project. Otherwise you'd have to start a brand new bridge and the local entity would have to pay at least ten percent. That's something to keep from a financial point of view. As a society I think we are interested in the substructure units at least being maintained or looking as much as they did originally. Even if it means facing the new concrete abutment with the old stone, or underpinning or some other reconstruction to maintain these foundations in an historic sense.

Joe Nelson:

We've made a complete circuit. Shall we send the talking stick around again so you may comment on what you have just heard and to add to what you have already said?

David Wright:

I understand why we've been doing it this way and I'm not complaining but one of the problems is that, I don't know about the rest of you, but as I get older, my memory gets less good. Consequently, I heard Jan say something, I say, yeah, I agree here and another question here, and so on and so forth all around the room. Trouble is when I get a chance to make not necessarily a rejoinder, a further comment, I remember what John said, but some of what John said is a little vague [in my mind]. So anyhow.

The question of historic fabric, I still say the focus still has to be on that. Now I will add the clarification that obviously if what you are talking about is good garden material, and not good wood, the historic fabric has already gone glimmering. If you see a stick that the center has gone out of, looks good from the outside, but the inside is not there, it is the illusion of the historic fabric, it is not the reality of it. So one shouldn't feel too badly and stay awake at night [on removing] that stick.

In fact, Arnold [Graton] told me a wonderful story about [that]. It was the Bartlett Bridge as a matter of fact that is father and he repaired in the late 1950s, early 60s. It had been abandoned essentially in 1939, some of the side boarding was missing from it, so the war years come and nobody did anything about fixing an abandoned bridge, or even thinking about it. They were probably hoping it would fall in the water and the problem would be solved.

Late in its career, however, a new floor joist had been put in and it extended on both sides of the bridge and they hadn't bothered to cut it off. So there was no sideboarding there and the floor joist was sticking out, under the eaves, the water poured off, hit the floor joists, splashed up onto the bridge floor, splashed up on the bottom chord so on and so forth. So they had a terrible time repairing the bottom chord of the place. They had to take out sections of it, recreate tension, jack the whole bridge, it was quite a little problem.

But, during the course of this work, one end of their scaffold sat on this elongated floor joist. When they finally got around to cutting it off, they found out it was about so thick, you know, tubular construction. So I guess everybody sat in a corner and had a cold sweat. But what might have happened, fortunately did not.

The point is, that wasn't really historic fabric, so we're not talking about that, we're talking fabric of the bridge which is in still good shape, could continue to serve if another thought were not entertained as to its removal for strengthening purposes or whatever. But as I say, it is stuff, it is physical stuff. When that physical stuff is gone you have something else. You cannot preserve, in my way of thinking, by removing, and by burning, or even storing in a barn somewhere. By storing in a barn, there is at least the theoretical possibility that the stuff could come back. But we all know here that that's not what's going to happen. There is no money for that.

The added load capacity for a bridge, I think, in many instances one can arrive at achieving some of that, so again, I would agree that probably trying to get the 18 wheelers through, think of the Kidder Bridge if you happen to know that one, I know Jan knows the kidder bridge because he looked at it and did a study on it. No way in the world would you get an 18 wheeler through that, try as you might, Some of them can't be upgraded but there are many of them can, to quite reasonable carrying capacity using traditional methods, at the same time taking care that these traditional are reversible, so you can get back to square one pretty much, if you need to. It's very important. And also, paying attention to the historic fabric that you have that's in good shape, cause that's the name of the game, I mean if you have a first folio of Shakespeare, and you tear out twenty pages of it and give them to somebody or throw them in the fire, you haven't anymore got a first folio of Shakespeare. I you remove fifteen pieces of a covered bridge truss that don't need to be removed for imperative reasons, simply because you are invading the monument in order to get greater capacity from it, you're not preserving the bridge, your not restoring it, you are doing damage to it, if you do enough of it you destroy the bridge.

Again, not to pound on Jan here because I know it wasn't his decision, and the work he did do there in the Cornish Windsor Bridge was absolutely first class as far as the framing goes and everything else. In any case, the point is that bridge, as Jan said, had a design flaw in it. It was over stressed by something like a factor of two and one half to one over the central pier, continuous truss over the central pier, that would be the highest tension part of it. That was under dead load alone, no chipmunks, no squirrels on the bridge, no wind blowing, and of course, no snow on the wood. And of course, no vehicles in it. The bridge had been revised four times previously to that, and the current and the current revision was the fifth one.

There was a clear choice there. It was either invade the monument, the trusses of the bridge, or correct the original design flaw, or add a supplementary structure. Now if you focus in on the idea of what the monument was, namely the trusses, and the upper and lower lateral bracing systems, the shed that surrounded it had the appearance from the 1950s, not from the 1860s. Exactly the wrong choice was made, the monument was invaded, it was significantly changed, the upper and lower bracing systems, there were two systems there. Now, they may have been somewhat ineffectual, in any case, they were both removed, pieces of them were reused to make a new upper lateral bracing system. The lower lateral bracing system, the original material was probably long gone, both because of rot from water dripping down through the floor, also because the ice had been up on that bridge a number of times, gnawed away and probably tore out some of the old lateral bracing system. But anyhow, the disposition of it was original, and the disposition is now changed. The bottom third of the trusses of that bridge were cut out and thrown away, most of it was burned in a field. A few pieces got turned into violins. And of course that was excellent spruce, so that article got featured in the newspapers and whatnot, not the fact that the lower third of the trusses were taken out, put in the field and burned. I looked over the spruce of those bottom chords. It was in a lot better shape than I expected them to be. I thought they would be much more rotted than they were. They were very good. As over stressed as they were, I could only find one failure at a shear block, which surprised me. I'm not saying there was one only, I could only find one, some of the stuff had been burned before I got there.

Anyhow, lets sum all this up, see the importance of the historic fabric, bottom third of the trusses are gone, upper lateral bracing systems both are gone, replaced with a new one of a new disposition, lower lateral bracing system, the distribution is changed, the lengths of the spans of both reaches of the bridge have been changed, they've been shortened, The roof rafters were all changed, I believe, the roof boards are gone, the sideboarding is all gone. Where is the original Bridge? Neither the original disposition of anything, neither the original material is there. It's a new bridge which utilizes pieces of an old bridge, significant pieces of an old bridge, but it's not the old bridge. It's Cornish Windsor number five, it's not Cornish Windsor four.

Jan Lewandoski:

The design is there, that's the other side of the question.

Dave Wright:

I would say not. The span is changed, the way in which that truss as a great machine responds has been changed because the ability of the glulam to resist is different from what the spruce was. It does not behave in the same way it is not of the same stuff. Certainly the ideas that go into the design of a bridge, there is no question about it, there is a lot of calculation that goes into this, there is all kinds of thoughts that go into it. If we can't talk to the designer, maybe the designer couldn't tell you if he was sitting in front of you might not be able to tell you everything. I'm sure there's projects that you do you would have a hard time explaining in language that someone who wasn't really familiar with it, it wasn't you, in other words, would understand why you took step A or B or C.. It's very hard to define sometimes.

Now, we can try to get at what the thoughts of the designer were. We can have thoughts ourselves in response to these designs. But we do have what is sure, what is certain, what is real, and what is, in many instances old, is the structure of the bridge, is the historic fabric. That has to be the focus of what we are talking about, otherwise, we're not talking about preservation at all, we're talking about something else. We're talking about pretty structures for tourists, we're talking about replication, which I am not against. There is no reason why, if a bridge burns, for example, it shouldn't be replicated. In fact, I'd make that part of the law: arsonist sets bridge on fire. He hasn't got rid of a wooden bridge for a modern one, he's going to get another wooden bridge. And perhaps if he tries to arson it for the second time, we'll catch him. Like the girl over in Woodstock who set Milton's bridge on fire there. She got two weeks in the slammer or something and a reprimand from the judge and was supposed to chasten her for the rest of her life. She was supposed to stay out of Woodstock for a certain period of time, too. Two weeks later she was on the square there saying that if they rebuild it, I'll burn it down again. Fortunately, she didn't.

It was amazing to me that they saved it at all, because it was the night of the fireman's dinner, or something like that, all the firemen were somewhere else and you know that firemen are not noted for drinking water, they use it to put out fires, but...they were all there in five to...ten minutes and put the thing out.

There's a third issue here and I have sympathy with several things which Phil said. One of course is the awesome problem of liability. I hear you loud and clear. Before I got involved in the Cornish Bridge I can tell you, I was substantially involved. I did a lot of serious thinking. I spent a lot of nights awake trying to figure out whether I wanted to do this and all the various implications of it. I know that feeling. It's not a joke. I think that the only real answer to it of course is, well, it's a partial answer anyhow, if the structure doesn't fail you're saved from a lot of your trouble. Being in a litigenous society, the trouble is that sometimes the fellow can do something completely stupid, turn around and sue the state or the town or whatever it is. If you happen to be the lucky fellow who was engineer of record, you may end up being a party to the suite. Where the structure hasn't failed, where someone has done something dumb sued and maybe the jury will believe him.

The other is trying to drive a bridge like the Kidder bridge beyond what is reasonable to ask it to do even with an upgrade of some kind.

Jan Lewandoski:

My only comments are, I was advocating qualitative analysis, but as John [Weaver] mentioned, if you could have a better quantitative analysis, I'm all for that. I'm just urging engineers who want to be just number crunchers, where there are many engineers that say "I don't even need to come look at a bridge, just send me the dimensions, I'll run the numbers, I'll tell you this is no good."

It isn't anything radical I'm suggesting, either because I've probably restored twenty-six bridges in this state and most cases it has involved picking a bridge up off of the river, taking the bottom chord apart, changing it, maybe structural work. And the AOT, I don't think has ever run notice on more than a couple of those. I did a talk in Scotland onetime. Engineers from around the world were uniformly astonished this could happen; that I could close a public highway, take the bridge apart, do major structural work on it, open the public highway again and perhaps no one would even come and look at it. And it has worked very well in my opinion. I think it was a very practical approach on the part of the AOT. They'd look and if things weren't failing, only rot, not bent and distorted in every way, they'd say just put it back the way it was. In some cases we'd make small changes and beef things up a bit, based on discussion really. It's different when you've got bigger spans or a huge amount of money being spent and so forth.

So that is what I am urging. I'm not saying engineers shouldn't be involved, but if you see a bridge and it's not showing any signs of failure under live or dead load, there's probably no reason to re-engineer that bridge.

David Wright:

When it comes to quantitative analysis, there are fabulous capacities for doing that now. Various computer programs, good as engineers as say Johnson, Parker Snow was. He didn't have at his disposal the means that we now have. When he repaired Town Lattice Trusses, as he did on the Boston-Maine Railroad, the analytical tool he had was an Equivalent Plate Girder analysis. Even though his was a fairly sophisticated one because he had a way of allowing for the fact that there were four chords and the outer chords would be taking more of the load than the intermediate ones were, and he had a way of working that into his Equivalent Plate Girder analysis, so it was fairly sophisticated compared to what some of them are. But it is nothing like what we can do now with some of the contemporary computer programs that exist. Never the less, it is very important that when one does make analysis of a covered bridge truss, or any kind of a bridge truss, but we're talking about covered bridge trusses, that they be modeled correctly. In some cases modeling it correctly is a good trick. The Town Lattice is a case in point. If you just set it up stupidly on the machine how many diagonals come and butt on the abutment, or the chord over where the abutment is, if you just set it on the abutment, which ever one of those things is close to the edge of the abutment, the computer will print out that's the one that is taking all the stress, that's not what's happening at all. It's much more subtle than that. You have to figure out too that there can be movement and flexure in the various joints with the tree nails, so you can spend a lot of time modeling that properly. Same thing with the arch. So I'm certainly not against quantitative analysis, but it's got to be done.

Another thing John [Weaver] said is very important. Let's make it into a kind of abstract proposition. If you've got a covered bridge that's been carrying known loads for a given period of time, you know the service conditions of it, you know the behavior of the bridge, the bridge is functioning well, you do an analysis of it. The analysis tells you it can't do that, well, the bridge is right and the analysis is wrong, or inadequate, or something about it is not according to Hoyle. It's a problem that has to be looked into. I'm not saying stop the analysis, find out how the bridge is able to do it. Look at it as close as you can. Maybe it's the design values for the pieces of timber. The ones that you read out of the NDS, that's statistical, its timbers from all different sources, sometimes they exclude a lot of the good stuff, they get right down to the bottom of the barrel with particular categories, we have design values which are in general true, but they might not at all be true about the particular stick which you have in front of you. And it's this specific structural stick that you're planning to use in your bridge, what it will do that's important. It's not what the whole category of them will do.

Ed Barna::

What does NDS stand for?

Dave Wright:

National Design Specification. There's two parts to it. That's the regulation part. There is a second volume to it [that gives published values]. It gives you published values and it gives you observations and rules and regulations about how wooden material is to be used. It has a very interesting disclaimer on it that doesn't get enough attention. "This specification is based on the best data and engineering judgements available, however, it is not intended to preclude the use of materials assembles, structures or designs not meeting the criteria herein where it can be demonstrated by analysis based on generally recognized theory, full scale or prototype loading tests, studies of model analogs, extensive experience in use that the material, or assembly, structure or design can perform satisfactorily in its intended end use."

You've got a lot of freedom, but the trouble is, once a fellow decides to go that route, if he gets into trouble, he has to be able to demonstrate on the basis of the things that are cited there that his procedures are legitimate, and sometimes that can't be done.

Ed Barna:

How will the policies we are evolving help with that? . . . [Sound wiped out for several seconds by Dave Wright rubbing his thumb on the microphone] . . . people making decisions. What is the current state of the art? What is generally accepted practice?

John Weaver:

I think every bridge is site specific. If you want to do a site specific evaluation, you have to hire qualified people to do a lumber evaluation like Wood Scientists do to give you an overall statistical picture of just what you have, right there at that one site. That can be further verified by destructive testing if you have the members to sacrifice to do that, but usually you don't. Usually you can't afford to sacrifice members to do destructive testing, but now at least wood scientist's evaluation, initial evaluation of what you have got to start with in your covered bridge you have to fall back on the more conservative values that you find in the NDS code, which are basically the five percent statistical values for lumber of that species in a larger group.

Ed Barna:

On the subject of putting steel beams underneath bridges to allow the wood to remain intact, I don't object to that. I'm not a purist about that. This is my personal feeling, I think probably the ideal compromise is made when Milton Graton did that bridge over in Waitsfield where he put the steel beams just far enough underneath the wood stuff there so if overloaded would bend down and touch it. The rest of the time it was still a covered bridge. There may be some moisture collection problems involved with the chords, I don't know just how that plays out engineering fashion, but . . . [John Weaver: He set those under the floor joists, so he wasn't anywhere near the chord.] . . . OK.

The abutments, I've always wondered whether things like the Freshet of '69, Flood of '27, took out so many covered bridges because they didn't have strong enough abutments, that they were washed downstream. I think the concrete things we have now are much better in that regard at keeping the flood from carrying the bridge away, I'm thinking for instance of the Gates Farm Bridge where the water came up pretty high on that bridge and it stayed right there. But it would be nice to have the original stones on the outside of the concrete work, but I think the abutments are a true advance as we have them now. Somebody who knows more about them might say more about that, but that's my impression.

It just occurred to me that one of the interesting areas for some comparisons could be made in value judgements in specificity of policies in the antiques world. They have to confront all the time the problem of married pieces, of having replacement pieces put on something which as all things do, they can break, they can wear, and there are criteria by which this can be acceptable or unacceptable. I think one of them is that you do not try to disguise it. I think it might be worthwhile to get a hold of some of the materials from the antiques people, or even talking with somebody whose knowledgeable in that field about how they arrive at their decisions on what they are doing when they are repairing things.

Jan Lewandoski:

I think we should pay more attention to stone abutments. I personally don't think concrete has anything to recommend it at all. Nothing in the State has taken the abuse that the central pier of the Cornish-Windsor Bridge has taken, which is large granite blocks [with rubble stone interior]. Fabulous quantities of ice and wood and debris. And all over the state you can see spectacular stone abutments that if the drainage is kept good and they are big and powerful enough, their structure is fine, far less concrete, which is a very temporary material. Right now, world wide there is a crisis with concrete, it's falling apart everywhere. You can build a mighty stone abutment if you wanted to. They are very beautiful. There are more people who can do good timber work than do good stone work right now, that's one of the problems.

Neil Daniels:

I want to urge that we work with representative Don Davis, possibly next year, that would be the second year of his two year term, in our preservation policy and the State preservation policy paper that had been circulated today.

Our heads are up against the ceiling on weight limits, and somebody needs to accomplish something because it's so easy for somebody, a town selectman or somebody in Montpelier to say, yeah, let's require this number of the builder, of the engineer, and it's so easy to say, so hard to do. We have to find a way to moderate the weight limits, because the other weights are going up and the timber can't stand it. Can't keep up with it.

Phil Pierce:

[There was a comment] about distinguishing new fabric from old fabric. The experience that I have recently participated in the State of New York, led to the replacement of a lot of fabric in a bridge, and the preservation office of that state did leave their ivory tower and visit our community and look at our bridge, and their remark was; "There is no need to mark new work to distinguish it from old." Which surprised me that they said that. I don't know how the Vermont preservation office feels about this topic, but I am curious to see if this group chooses to go on record with a recommendation of thou shalt mark, thou shalt not, for instance with some kind of . . . It could be done with some kind of stamp, some kind of mark can be made.

I'm curious what the group feels about roofing materials, whether it is imperative to maintain a specific type of roofing material, and lastly, I'd like to open it up for answers; we're getting ready to open up our third publicly owned bridge in our county for which there will be substantial replacement of material and does this group have interest in an attempt to preserve any of that fabric.

Ed Barna:

Give me your address, I think I know a guy in Hubbardton who might want it.

Dave Wright:

[Answers to Phil Pierce three questions] One [of the questions] was the dating of the material. Certainly what new material gets put in there should be very well recorded. There are drawings of record, certainly of the three bridges in Delaware, I'm sure there are detailed drawings about them. What's new and what's old should be clearly indicated on those. That tells you, when the bridge is done so you know the date of all the new material. I wouldn't have any problem if discretely in various places, you had a date on them, or if you didn't have a date on them, as long as it's recorded. That touches on another subject however. That is, often when one of these bridges is to be restored or rehabilitated or beefed up or there are not really good drawings of record made of the bridge as it was found at the start of the project. And there are often not very good photographs made of that. Everything ought to be photographed, everything ought to be drawn. I know it's a cost, but never the less we are talking about principles of preservation here. We ought to know exactly what the start of the process was because the next step may or may not make sense. That ought to be part of the preservation process before the bridge is touched.

[Another question was] roofing material. Aesthetically speaking, many of these covered bridges had a wooden roof on them, so it would be nice, aesthetically speaking, to have a wooden roof.

Phil Pierce:

Does anyone know of an original construction that had anything other than wood shingles? And slate? I'm not aware of an original metal roof.

Jan Lewandoski:

They were around in the 1890s and even before that. There may have been some bridges that had them, but I don't know of them. The Windsor Bridge hade them at an early date I know.

Dave Wright:

Yeah, but it was originally wood.

Jan Lewandoski:

But by the late 19th century it was metal.

Phil Pierce:

The reason I ask this question is I've taken a lot of grief on one of our bridges in Delaware County to use metal on a bridge that's had metal for fifty years because I didn't want wood shingles on it. Because I believe wood shingles tend to shed snow slower. I insisted on metal. I took a lot of heat over it. I'm curious if this group wants to be on record with some opinion on what to do with a roof.

Jan Lewandoski:

I've seen roofs come and go.

Dave Wright:

I love a wooden roof. But I think it is harder to get, in this area it was probably white cedar, it's hard to get the quality and quantity of the white cedar which was once readily available. On the Cornish-Windsor, they were three-feet two-inches long or something like that. . . .

Joe Nelson:

A practical question would be getting the towns to maintain their bridges. The standing seam metal roof is probably going to be longer lived.

Dave Wright:

And Phil's point is a very good one, it sheds snow much more easily.

Ed Barna:

[re;] Sanderson Bridge, AOT view on it was that metal roofs had been used for so long that they were historic enough.

Dave Wright:

The usual way for proceeding with these covered bridge restoration projects: They are designed either by the highway department or by consultants they've hired, design is elaborated, it gets various approvals, then it's put out to bid and sixty days later the fellow is supposed to be on the scene doing the job. That's not a very satisfactory system. There has to be a way of getting more guys like Jan Lewandoski, like Arnold Graton, like Tim Andrews, to mention three, Neil Daniels to mention a fourth., I don't know them all. In any case there's got to be a way of getting more of these folks doing this work. They're the ones who have the real experience in how to handle timbers, They're the ones who have an immense amount of experience. Like the paragraph from the NDS. They know things about wood, that someone who's less familiar because lacking the practical experience, say a master bridgewright or a house wright would have. That should be on the table. If it is excluded from it, we're going to get less good jobs than we would otherwise have.

Joe Nelson:

One of the things that concerns me is the comment that I've heard about what has been termed as the methodical destruction of our old bridges beginning with the Henry Bridge, followed by the Paper Mill Bridge, by the Fuller Bridge, and the Gates Farm Bridge, and finally the Hopkins Bridge.

I've heard people exclaim that it's all the fault of the committee that has been designated to guard these bridges; the preservation division of the VAOT.

You wonder what makes things work out that way. I've concluded that in at least some of these incidents, it seems to be pointing at the owners of the bridges. They're the ones that determine how this bridge is going to be restored or replicated or whatever.

Here is a little case history I brought along to share with you. It's the Union Bridge in Thetford. A selectman told me that he and the town were determined that this bridge was going to be preserved as it was and its appearance would not change from the old times. They valued its historical value to the town and they want to maintain it.

The Engineering study of the bridge gave them three options. The first option was to replace the defective members of the bridge. And the historic fabric of the bridge, of course, would be maintained. The most [capacity] they could get out of the bridge was something like eight tons.

The second option was to do all of the things they would do in option one, but they would take the floor out of the bridge and replace it with steel beams with the notation that the steel beams could be removed at some time and the bridge could be restored to its original condition.

The first option [cost was in the order of $500,000. Add another $300,000 onto that for option two. Option three would cost $200,000 more than option 1.] The second option and the third option [would increase the capacity] to twenty tons to afford the passage of a fire truck. a whole new floor system, and in addition to that, almost all of the diagonals, and half of the kingposts, verticals with different dimensioned lumber because there wasn't enough space on the butts of [the kingposts] in order to do the bracing. Another $200,000 on top. Amazingly enough, they opted for [two]. Not [three], not one. [The most costly at $835,000.] That's what's happening to the bridges.

Jan Lewandoski:

Who is the engineering firm?

Joe Nelson:

Hoyle Tanner. I have their recommendations here. Apparently they did a very thorough job. And they gave these three options. The town had the option of restoring the historical integrity of that bridge or not. They chose not.

What I would like to do is get this paper together (the preservation policy) and slant it towards non-engineering people to kind of help educate them as to what the options are, what they are gaining and what they are losing. To help us educate the townspeople, and incidently, when I organized the concept of the Bridge-watch areas I had this one thing in mind.

The people in the bridge-watch areas and who are leading the bridge watch area are taxpaying citizens of that particular area. So they are insiders, and they should be able to go to their municipal government, the select boards and all the other parts of that municipal government as people who are sharing in the benefit, the pluses and the minuses of doing something with that bridge. Their tax money is going to it. For somebody outside, even if part of the VCBS, who [have no economic stake in the town, such] as sharing in the cost of having that bridge built, wouldn't be listened to, and they shouldn't be.

So what I wanted to do then, is to organize insiders all over the state to watch those bridges, because those insiders have to be listened to by their elected officials.

And here is where education has to be [directed]. Towards the people who make those decisions as to how they want their bridges to be restored and maintained, and whether or not the bridges are going to be maintained.

Neil Daniels:

Are we all aware of the progress of the Poland Bridge? John Weaver's name is on it, he did an excellent job . . .

Jan Lewandoski:

Is this the stabilization work, or the other?

Neil Daniels:

This is the stabilization work, this is part one. He did an excellent job of coming up with some steel tension rods that are fastened to the lower chords and are hidden from the outside by the boarding, and some other metal inside. But there seems to be not much knowledge about phase two, what it would carry the bridge to.

Dave Wright:

It sounds as if he knew Howe.

Neil Daniels:

Yes, John is very skilled in that.

Dave Wright:

That was a pun [I apologize for that].

[This file originally posted March 25, 2002]