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Middlebury Bridge Committee Reviews Pulp Mill C.B.

by Joe Nelson¹

Middlebury. Vt., July 15, 2005 - The Middlebury Bridge Committee met to review the town's bridge site analysis process, and transportation needs such as emergency service and traffic management. Much time was given to the Pulp Mill Covered Bridge, its history, the importance of its site to the town, and options for its future.

Project manager John Weaver provided an overview of the bridge and its current condition using photos to assist in his presentation. Preliminary plans have been developed and were provided.

Invited to the discussions were Deputy Historic Officer Eric Gilbertson, of the Vermont Division for Historic Preservation, and Jan Lewandoski, owner of Restoration and Traditional Building, the bridge-wright who has done the most recent work on the Pulp Mill Bridge.

Also invited were engineers from the Engineering firm McFarlane-Johnson, Inc. of Binghamton, N.Y. and the Weybridge Selectboard, and the public.

The speakers were introduced by Skip Brush, bridge committee member.

Brush: "We've spent the last several months to look at what alternatives there are for an additional bridge across Otter Creek to carry a full load of traffic and we preliminarily concluded...that there really is a need for two crossings in town. We need to get one established before we can address some of the other transportation needs... . The only other crossing beside the Battell bridge is the Pulp Mill Bridge, and that's a circa 1810 covered bridge which obviously was not built for modern traffic size-wise and weight, and it has a number of structural problems that we need to address no matter what we do. The ideas quoted are: we can replace the bridge, we can build a parallel bridge, we can build a new covered bridge that could carry emergency services.

"[We have invited Engineers from McFarland- Johnson], Jan Lewandoski, our covered bridge expert throughout the state of Vermont, and he has done a significant amount of work on the bridge and has done historical research about the bridge. We have invited the Weybridge select board...because they own half the bridge.

"The reason this has turned into a warned selectboard meeting is because we have five of our selectboard here which is a quorum. It hadn't been intended as a selectboard meeting as such, its more a bridge committee meeting with the select boards of the two towns and the experts to try to focus in on what we can reasonably and practically do with particularly the pulp mill bridge site and then [visit the pulp mill site] then afterward continue the meeting looking at the cross street bridge site to see what ideas the engineers have on design-build concepts there. After that there will be a tour of the Carrara pre-stressed concrete plant."

Fred Dunnington, long time planer for the Town of Middlebury reviewed potential bridge sites and [will explain] why we are zooming in on the Pulp Mill Bridge site and the Cross Street Bridge site.

Fred Dunnington: "We looked at a new or parallel pulp mill bridge as an option, we looked at something in the area of the railroad underpass...Seymour Street over to Weybridge Street as a route, the Cross Street which we build from the intersection of Main and College Streets.

"Criteria considered in the selection of the best site for the in-town bridge are: Number of historic properties taken; The environmental issues; The traffic benefits as compared to others, we narrowed it down to five options. [Lucius Shaw Lane, and Weybridge Street. South Street to Creek Road, Middle Road, Creek Road to South Street Area, the site of the former Three-mile Bridge.]

"The committee had an evaluation rating system that it used to build upon from an earlier effort in 1981: We looked at the relative traffic benefits, the effectiveness for emergency vehicles...the effectiveness for facilitating repairs to the railroad bridges... impact on school traffic, the impact on future growth areas, environmental impact, historic impacts, ecological impacts, overall costs with some preliminary cost estimates for weighing these. Bridges cost by the foot, as do roads, the longer ones are proportionally more expensive. Potential sources of funding for these, effects on other town roads, neighborhoods, the traffic effects for each terminus, and so fourth.

"Individual members of the committee did these ratings. Some issues like emergency access was more important than others. While actual scores varied a little bit between members, the results pointed out that the Cross Street bridge would be the best solution taken together. It doesn't mean it's the simplest to do, its relatively short compared to some others, and doesn't adversely effect some residential neighborhoods the way some others would.

Through all of this the committee came to the realization that regardless of which does the best we still need to do something with the Pulp Mill Bridge. That needs to be there anyway, it either needs to be rehabilitated once again, or replaced or paralleled or something. So at that end we attended a meeting with Jan Lewandoski and the Covered Bridge Committee and the Agency of Transportation, we learned some new information about this, it isn't as historic as we thought, there are some inherent flaws in it that will influence what decisions are made here, that is an important part of today. That is the process we have been through, we are going have a public forum and produce a report of the findings. We are in the process of gathering information for this and so we wanted to schedule this more public setting as an interim report for everybody.

Eric Gilbertson: "[As deputy State Historic Officer,] I sit on the State's Covered Bridge Review Committee. The Pulp Mill Bridge is on the National Register of Historic Places. It's the only double-barreled covered bridge in Vermont...and the work that's done on it should really meet the Secretary of the Interior's standards which sets the standards for dealing with historic preservation projects, you should replace things in kind if possible, and the general configuration of the bridge shouldn't change. Of course, fixing broken things is fine.

"Lets talk about the state's Covered Bridge Review Committee. I think it is unique nationally and [it convenes] if the Agency of Transportation is involved in a bridge project. It is a combination of people coming from the covered bridge society, the town . . . that needs to look at covered bridges, [and the AOT] engineers all sit there. It's been going on for at least a couple of years now and it's based on a covered bridge plan that the state has...It basically seeks to preserve Vermont's covered bridges and one of the things that we have put in the plan is that keeping a bridge in use is important in its preservation for a couple of reasons. One is that there is a reason to maintain it, and secondly, there is money available for bridges that are in use that is not available for bridges that are not in use. Senator Jeffords has put a significant amount of money into covered bridges nationally and in Vermont as well, several million dollars a year and that money is not available for bridges that are not in the transportation system."

Question from the floor: Given a critical need to cross the creek, we have the Battell Bridge in the center of town. The town needs to provide an additional emergency access across a bridge that can carry modern fire trucks and ambulances and we also need to accommodate some up and coming transportation problems. Assuming the Pulp Mill Bridge, or the location of the Pulp Mill Bridge is the best location for a new bridge. Considering what you just said, how would you address that?

Gilbertson: I'm not a transportation planner, but I'll give it a shot. We have dealt with situations in the covered bridge committee with covered bridges where significant upgrades in strength was made. The way that I look at it, I'm not sure it's consistant with all the committee, we look for the best possible way to do that. When the committee started, we dealt with the Windsor-Cornish Bridge, a two span bridge, and the State of New Hampshire, in their wisdom, passed a law that it had to be H20 loading which means that it could carry semi's, and we were able, through some clever thinking, and some clever engineering, to get that bridge to meet that H20 standard, based on making it one-way, and using continuous glu-lam beams 160 feet long in the bottom chord. So there are ways to deal with that. I don't know this site well enough, but we have on occasion, put steel under bridges, certainly not a favored [practce], and it is usually used more as a safety piece. The bridge doesn't actually rest on the steel, but the steel prevents the bridge from failing."

Selectman Peg Martin: Two things you said. One, you said, keeping it in use. And frankly, by keeping this bridge in use, we're killing it. We can probably take some of the measures you are talking about to strengthen it... . In this instance our problem is not the wish to preserve the bridge, we cannot do anything to this bridge to allow it to carry ambulances, fire trucks, any kind of a major emergency vehicle, due to the size of the bridge. It's a wonderful bridge, but they do not fit, and believe me there are some who've tried. We have an issue here, a problem that is serious.

Gilbertson: "I think that what you are doing is the right thing, to go through a process looking for alternatives [to] make a decision, and I am certainly willing to participate in that process, and make my opinion known offering comments or alternates. I know there is thoughts about a Cross Street Bridge."

Question [Bill Perkins]: "You mentioned that some money was available only if the bridge continues in use. Does that mean the use cannot be changed?"

Gilbertson: "As long as it's still in the transportation system. [Pedestrian and recreation path use? I'm not the authority on that.]"

Selectman John Tenny: [...We have tried to be good stewards to our historic bridge and we have done numerous projects, repairs, and restorations and a good deal more can be done there, we are falling below the top as the level of usage [of the bridge] continues to increase, and the intensity of that usage is ruining the bridge, so we are not providing the transportation the community needs either for traffic or for safety of emergency vehicles, nor are we preserving the resource, we are slowing its demise.]

Gilbertson: "I understand...I think Middlebury has the worst traffic problem than anyplace in the state, one bridge going though town and all that. I'm sympathetic to that. I look for the best solution, not necessarily the ideal solution, I doubt if we are going to find an ideal solution. The ideal solution would be to find the money to restore that bridge limited to light use traffic, cars and trucks, and have another bridge for other traffic. Are we going to get there? I don't know. The ideal preservation goal is to restore that bridge to light traffic."

Question: How would you feel if a new bridge was built alongside the existing Bridge?

Gilbertson: We have done that in places. There is one planned down at the Creamery Bridge in Brattleboro, probably not going to get built for a while. We just reviewed the plans to upgrade the covered bridge because plans for the new bridge are off somewhere in the future and it's a temporary solution. One definition of temporary is anything short of forever. To me it's not the ideal solution because it's a visual thing, but is it a solution that would work here? Certainly...There is a federal regulation that if you use federal funds to put an alternate bridge in, you can't use federal funds to fix the old bridge. If the new bridge was at a significantly different location and the Pulp Mill Bridge maintain that local light traffic, then [federal money could be used on both bridges], it is my understanding.

Jan Lewandoski: "[The pulp Mill Bridge] I know it well because I have worked on it extensively, three different periods of about three months at a time. I know its strengths, I know its weaknesses. Two things to clear up: The date of the bridge. When I first worked on it, the date that was being kicked around was 1812 to 1820. It didn't look right to me. The timber wasn't long enough, big enough, or good enough for that date. I went to the Weybridge town records and found miscellaneous things but the most telling was a note, a selectman's order to pay a person to go to Essex to look at a bridge, to get the design for the bridge at the paper mill, it said. And in Essex at that time, John Johnson was a builder in the Burlington area from the 1790's to the 1830's. It was a big double barreled [bridge] with Burr arches like Pulp Mill. I believe the person went there, looked at it, didn't look at it carefully enough and came back and they made a crucial error when they built that bridge. That's one of the things.

I told this to Lola Bennet who works for the Historical American Engineering Record for the National Park Service. We were doing a project on covered bridges a couple of years ago. She went further [in the] Middlebury records, she found enough other selectmen's commentary and cost figures to convince her that 1851 was the date of that bridge. It may not make it the oldest bridge in the state [but] it is an historically significant structure in every way.

"The bridge right now does not reflect the framer's original intent. The bridge was built with 200 feet of clear span originally. When we're walking on the bridge today, I'll show you how I know it. It's quite clear to see. The kingpost that is intact is in the middle, meant to carry braces in both directions. All the other kingposts took braces running away from the middle. Probably not long after it was built, it started failing. Not long after it was built, arches were added, a plank arch, made out of six-by-tens. After that, a laminated arch was added to reinforce it (formed over the original plank arch by Deacon David E. Boyce about 1859-60 per H.W. Congdon in The Covered Bridge, 1941). Nobody seems to know when they divided it into three spans. When you take the abutments into account, they are only about 60-feet a span, each one of the three.. To do that, they had to do dramatic things to the bridge. They had to reverse the direction of half the bracing. And because the posts didn't have shoulders to accept the bracing, they had to bolt shoulders on and move the braces over. They didn't change many of the posts. The posts got very distorted. Let me go backwards a little bit. The mistake they made in building this bridge was largely, well, 200-foot is a big span, you need a very powerful bridge to go long, with a very deep truss, and there are ones that succeed in doing it. There is one in New York State that's 228 feet in a single span and it still has positive camber. It can be done. The trusses are a little small on this one, but the big error, the kingposts are necked down and dropped between the chords. [The kingposts] both pick the chords up and the kingpost also takes the load delivered on the brace that carries all the weight further on the bridge. They didn't shoulder the kingposts into the chords at all, nor did they put a sheer block behind the kingpost, and I'm not even sure they had a kicker brace at the bottom, they had them at the top. All they had was a single bolt transfixing the bottom of the kingpost. The brace starts delivering a load down to the kingpost. The load accumulates as it goes toward the abutments and becomes very large. Fifty-thousand pounds or something like that. One bolt, a necked-down piece of timber that can slide between the chords. At all of the heavily loaded locations, the post is first bent, both top and bottom, distorted a bit, and then cracked around the bolt and pushed backwards. As soon as you start getting those small differences, you start dropping the bridge. The people knew about it right away.. They started by adding arches, eventually they sub-divided it into three bridges.

"As I look at the bridge now, a very interesting bridge, but from the aesthetics of framing, I say the framer tried to do something, he failed dramatically, yet the thing is still standing. The bridge had a problem right away and you've been remedying it ever since.

"I want to insert a sidebar here: The chances of catastrophic failure of any span of that, it's a big bridge, its meant to be 200 feet, dropped down to 60-foot spans...There is so much timber piled up in that bridge...No one is going to drop your car through the bottom of that bridge, I don't believe. Even the floors, the bad condition they are in, I don't think its going to fail, but it gets worse all the time.

"Dan Webber and I worked on the ice last winter, underneath the bridge. You can see where its problems are. Cracked post bottoms, canting of shear blocks, Lower chord bowing outward, its got lots of problems, but catastrophic failure, no, continual degradation, yes.

Both programs that I carried out were largely to undo bad work done in the 1980's. You spent $283,000 I think then, and I had to take a lot of it out and replace it. Short pieces of heavy timber, butt joints with a steel plate across them, bolts with no shear rings and no shear blocks, bolt holes a quarter of an inch bigger than the bolts, things like that. Post bottoms not repaired, I've had to replace numerous posts. You've got that problem, you still have that problem in lots of places on the bridge. There is a rotten top chord, that can be fixed, but, the big laminated arches put in in the eighties have gone negative. I think Gil Newbury of the AOT once analyzed them. He said maybe the arch on the tall center truss is okay, the ones on the outside are just too flat to ever work. I re-footed two of them and beefed them up in the areas I was working in.

"The bridge has three trusses and is divided into three spans, so there are nine sections you could work on where it springs and jumps across the river. I worked on two of them, maybe $75,000 apiece or something like that. The other seven all need it too. You can send five or six hundred thousand dollars on the bridge, plus, I'm looking at cleanup. The floor system which is all new from the 1980's. You can take forty percent of it away and you'd improve [the bridge]. The floor system is full of useless material [contributing to] floor loads. You can probably take away enough floor equal to the total live vehicle load the bridge ever gets on it. What I'm getting at is that the bridge is not going to fall down and the weight of vehicles on it isn't going to kill it and if you take away enough floor the weight of the vehicles will be somewhat negated.

But, the entry is too small. The bridge is littered with side-view mirrors. Anything of any size cannot go through that bridge. It's not a question of weight going through that bridge. The bridge's own deadweight, the weight of the floor is bigger than vehicle weight. It's geometry is too small.

"I'd preserve that bridge and build a new version of it, 200-foot span, multiple kingpost, down the river somewhere and let heavy vehicles cross. Well, that's just a personal opinion."

Question: You said to preserve the bridge. You mean there?

JL: "I wouldn't take it off the site. I think the site is historically important too."

Question: How would you feel about building a new bridge right beside it and then using the old bridge for light traffic [and the new bridge for heavy traffic]?

Lewandoski: "I don't think vehicles are [damaging] that bridge right now. I think the same way Eric does [about a parallel bridge] I think it's visually distracting, but better than destroying that bridge. When I look at that bridge, I shake my head. It's a shame they didn't do a couple of things different in the year 1851, you'd have a great bridge there."

Question: If I understand you right it's bad work done on the bridge, not the traffic that's the problem.

Lewandoski: "Bad work done in the 1980's particularly, which was probably replacing work that had gone to hell, got rotten, but you could fix those trusses and do sixty feet so easily, just the design of the trusses, you could make the bridge fine in just three sixty-foot spans. But the extra weight of the floor, which is there all the time, is as bad as any cars going across it. . . But I think, the floor, floor joists, stringers, a whole layer of three-inch plank and [another] whole layer of three-inch plank, joists and a layer of three-inch plank [could come out]. You could even take the underfloor bracing out."

Question: If this bridge was left where it is and a parallel bridge was built to carry traffic, would there still be pretty much the same money having to go into the covered bridge?

Lewandoski: "Yeah, I think so, I think the bridge still needs a lot of work, maybe a little bit less, but not much."

Question: There wouldn't be a whole lot of money saved on the Pulp Mill Bridge by building a parallel bridge?

Lewandoski: "No, you still have to fix the Pulp Mill Bridge."

Gilbertson: "That's what we found as well, fixing the bridge for pedestrian use [or vehicle use there is not a huge difference in cost] you are going in there doing the work anyway, and there may be a minor difference."

Lewandoski: "You know, these issues of pedestrian bridges, automobile bridges, I built a bridge in Guelph, Ontario one time, and because it was going to be heavily used by pedestrians, we ended up with a heavier flow load than vehicle load . . . "

Question: How long before the [Pulp Mill] bridge fails? Years?

Lewandoski: "Decades. The Pulp Mill won't fall down for decades. If you keep a roof on it, It may never fall down. It will just get so a brace will fall out, or a bottom chord will break and it'll really drop and then the town will close it. I don't think it's a life-safety issue, I don't think anyone will be killed in that bridge..."

Gilbertson: "The weight of a vehicle on that bridge is an insignificant part of the total load on that bridge. The weight is in the bridge [itself]."

JL: "Two feet of wet snow on the roof probably weighs more than all of the vehicles."

Fred Dunnington: "...the people who bought around [the bridge] will be very concerned, almost sure to be opponents of replacement with a new bridge, [or a new bridge] along side [the old], as a practical [problem] we really have to think about how are we going to get something approved. It took a long time to get the Cross Street Bridge to happen, I predict that it is going to take a long time to get people to agree to move or to sister this [bridge], given the funding and political obstacles. So I wonder if, as an act of historic preservation, we should not interpret the very mistakes and flaws. This is off the wall: Suppose you took that bridge and put it in a location where you could interpret it, explain to people the history of covered bridges, how things were reversed, how people tried to deal with it, and how we learn from this process. And also in the act of historic preservation we built a new covered bridge there following traditional principles and make it large enough to hold a fire truck, that the people in the neighborhood would go along with. We would have met our objectives of getting emergency vehicles across and would be honorable to the cause of historic preservation and covered bridges and maybe you could attract money for it."

Gilbertson: "I think if you start costing that out, it would be really expensive to move that bridge to some location. We talked about that for the bridge down in Weathersfield. They talked about moving it off the site and finding a place for it. I think you'll find a lot the repairs Jan talked about are going to have to be done anyway. Moving the bridge is going to stress it at least as much as any loading will do, I would guess. I think all of the alternatives that have been put on a list, this would not be the ideal historic preservation solution, but it is something I'd look at. The obligation of the town to maintain this bridge on whatever location, a dry land location, that obligation is going to be there, and I think, looking at those costs years out, and its not going to serve any purpose. The beauty of having a covered bridge working, and serving a purpose, there is funding for. But I think you should look at all the alternatives....

Skip Brush: We discussed a number of times on the bridge committee about putting a bridge right beside it. Can we do that? It seems to be a reasonable solution if we can get by the neighborhood impact of having the new bridge beside the old one . . . Is there anything from a historic preservation point of view where we can just take it out of there and eliminate it? Or are we not allowed to do that?

Gilbertson: Nobody is going to arrest you. I think what [would happen] if you did that, is that they will probably make it very difficult for you to [use federal dollars] because of the historic preservation. You would be destroying a historic (site). And they would certainly make you look at more alternatives to get to that point. I don't think you should necessarily take the option off the table. Not that I want to lose a covered bridge. I would certainly voice against that in my official capacity.

Question: You said preserving the existing bridge where it is for whatever use is part of the solution and the other piece of the solution is getting access for emergency vehicles

Gilbertson: That's what I say would be the ideal solution, because obviously the limitation of this bridge is not only its weight capacity, that is a problem that can be dealt with. I think that bridge can be fixed, rehabilitated to the point where you could carry fire trucks on a limited use basis, I don't think you'd want to run 50,000 pounds over it [on a regular basis]. You're not going to make the [entries] any bigger to get into it.

Lewandoski: You could beef that up so you can carry [the emergency vehicles] but they won't get in the opening. You'd have to raise the roof and move the trusses apart.

Question: You commented on spreading the trusses apart to make it wider. Would that work?

Lewandoski: ...if the spans are kept short, spread those three trusses apart, the floor system is all new anyhow, I'd love to see the floor system changed anyhow, you'd lose the roof system, or some of it, and you can drop the floor lower by changing the floor system, you might get a bridge that has a lot of itself still there, and is bigger.

Question: What do we preserve if we make a new bridge out of an old bridge?

Lewandoski: The Trusses.

Bill Perkins: I'm confused. Why are we talking about repairing the Pulp Mill Bridge, building a second crossing at Cross Street, and considering another span beside or near the Pulp Mill Bridge. It seems to me, what we really would be talking about, [is] a second Cross Street, and as a separate issue, be dealing with the preservation of the Pulp Mill Bridge. Suddenly we're talking about three bridges here. It's very confusing to me.

Brush: I think, my perspective, we need to do something at Pulp Mill Bridge because we need to fix the bridge, number two, to provide an alternate crossing for emergency vehicles before anything can happen either on Cross Street or the railroad bridges because without that alternative way to get across the creek, any one of those projects will...shut the town down.

Perkins: So you're talking about possibly a temporary second bridge at the Pulp Mill location? A bare bones heavy duty bridge?

Skip: I suppose it could be a temporary bridge. In my mind, it should be permanent. The town needs more than one bridge.

Don Keeler: If you're just doing this for reasons of emergency access, this is not the ideal location in terms of where the majority of calls go for ambulances or fire. We're talking about this one because it happens to be a narrow span and because other options are not cheap or easy. But at the end of this overall process, what we need to do regardless is repair the Pulp Mill Bridge, and do it right, the benefit of having another one next to it, in the long run it will be worthless. If we can steel ourselves to have the courage to find something else that is more workable, it'll be better alternative for the down-town congestion that is going to happen with the railroad bridges and its better for the emergency services than this site.

The morning session concluded with a tour of the Pulp Mill Bridge led by Jan Lewandoski. The afternoon session took up the Cross Street Bridge Design and build, engineering and permitting, and approaches and intersections. The meeting closed with a tour of the Carrara Pre-stressed concrete facility.

[1. This meeting was audio taped. The tape was transcribed and edited by Joe Nelson. If there are inaccuracies in the transcription or errors in the identities of the speakers, please contact him so corrections can be made.]

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