The top issue selected by the Historic Bridges CoP members is:
As noted in my email to CoP members, I ask that you all think about how to most effectively address this issue and post your ideas starting tomorrow morning (Wednesday, the 22nd); and please provide comments and suggestions on each other's postings. Consider what can be accomplished in the short term and in the current economic climate. The goal here is to identify and discuss actions and practices transportation agencies and their partners can implement today or within the next year or two.
Terry H. Klein, SRI Foundation
Key to solving this challenge is having an engineer and a historian who both understand historic bridges work together. The traditional approach to project development of keeping the two processes (design and historical compliance) separate only serves to perpetuate and even exacerbate the rigid and entrenched positions of the two sides.
A more effective approach is the collaborative process used in Minnesota (see the Mn/DOT Historic Bridge Management Plan) for several recent projects including the Historic Stillwater Lift Bridge. In this approach, the project historian and the project engineer work together from the outset to develop treatment recommendations for historic bridge rehabilitation.
Both consultants participate together in a field review of the bridge and subsequently meet face-to-face to work through proposed treatment options, design requirements, and the requirements for compliance with the Secretary's Standards. When design recommendations are brought to the DOT and/or SHPO, the proposed treatments should meet both project needs and be in compliance with the Standards. Parenthetically, it would be helpful to have a version of the Secretary’s Standards that more clearly apply to historic bridges; however, this can be extrapolated from current guidance. Remaining questions are discussed by all parties in a larger collaborative session involving the historian, engineer, DOT, and SHPO—and importantly, compromises on both sides may need to be made.
This process is intended to shorten the back and forth of recommendations as they are passed from engineer to DOT to SHPO for comment, and back to DOT and back to the engineer for revisions, with the historian (if there is one) somewhere in the middle providing input, but not necessarily active participation. Successful collaborative outcomes rely on a spirit of cooperation and compromise on the part of the engineer and the historian, as well as the client and review agencies.
I was disappointed in the selection of the top issue by our group. The issue of let me call it quickly Boltsvs. Rives is a non issue in the saving of historic bridges. It is a good conversation topic between historians not bridge designers. It leads to negative action when the survival of a historic bridge is in jeopardy.
I believe that the second topic is most appropriate as it gives the bridge owner a " good excuse " to save the structure. The owner needs to be educated what can be done via load rating, non-destructive testing, changing the service, etc.. which requires money. and recognition.
I see no need to elaborate on the Bolts vs. Rivets topic.
Abba
We worked with the Maryland Historical Trust to develop a program to preserve as much historic fabric of the bridges as possible. We tested samples of metal from the bridges and found that the historic metal was always stronger than the default strengths for the period. This allowed us to use higher allowable strength in our calculations and therefore save more members at the load capacity we were trying to support. We had a goal to get a 15 ton rating so small emergency equipment and school busses could cross.
Annother approach was to identify "wear items" of the bridge, such as the wood deck and stringer beams. In our experience we found that untreated rough sawn decks lasted about 8 years and painted steel stringers lasted about 15 years. Therefore these had been replaced many times in the life of the bridge and so we defined them as wear items and not original fabric. These items also caused the maintenance crew constant repair work. We coordinated with MHT to replace these with glue-laminated treated decks and galvanized stringer beams. The glue lam decks distribute loads better than the wood planks and therefore help stringer and floor beam ratings. This combination seems to be working very well and giving the public good service.
My office, the New Hampshire SHPO, has begun to apply Guidelines for Historic Bridge Rehabilitation and Replacement to an actual bridge project over the Connecticut River between NH and Vermont. The bridge is a three-span truss structure (two high trusses, one pony) dating from 1937. We have found the Guidelines to be built on real experience and therefore to be rich in potential as an evaluative and planning tool. But we have also found that rigid approaches on the preservation or the engineering side of the conversation will quickly kill the usefulness of this tool, as will rigid application of current bridge geometric requirements. We also see that if any party tries to dominate the discussion or manipulates the Guidelines to create a preordained outcome, all the potential in the document is quickly lost.
We've learned that in using this tool, there's no such thing as having too much information. The Guidelines are probably best used, in fact, as part of a context-sensitive study that takes into consideration much more than the bridge and its approaches--that ideally studies the bridge as part of an organic community and as a chapter in local transportation history. This is particularly true because the Guidelines ask users to determine whether a bridge is "of average or high historical significance"--not an easy question and one that is not usually addressed in determininng National Register eligibility for a structure.
In keeping with suggestions in the Guidelines and our own office practice in trying to apply the Secretary of the Interior's Standards for Rehabilitation to bridges over the years, we agree in principle that the entire floor system of the bridge may be replaced and that the upper lateral and sway bracing may be modified, if necessary, to attain greater vertical clearance. We agree that certain deteriorated wide-flange truss web members may be replaced in-kind. By these means, the bridge can be returned to an adequate live load capacity.
But we have found (as predicted in the Guidelines) that bridge geometry and safety aspects may be harder to deal with than structural capacity. So far, we have not seen much flexibility offered by others in these areas, although the conversation is just beginning. From our perspective at the moment, it seems that rigid interpretation of geometric and sight-distance guidelines can be at least as detrimental to bridge preservation as rigid approaches to historic preservation criteria or rigid interpretation of structural engineering guidelines.
When engineers evaluate whether an historic bridge can be rehabilitated they have to make a detailed study of its condition, structural capacity,safety systems (mostly railings) , geometrics of the roadway , i.e. lane and shoulder width and hydraulic capacity.
Either we can or cannot improve its condition and structural capacity to what is needed. We have many methods to do this and if it can be done in an economical (prudent) manner as compared to replacement we have a rehabilitation project (based solely on these paramenters).
We will always have differences of opinion between engineers and historians regarding what effect the addition of reinforcement to the bridge has caused but this is healthy and it makes each perspective really think about what is important. We have come a long way in educating each other. In my expereince we have usually come to agreement.
Where we struggle is with safety systems and geometrics. We have on one side the engineering community headed by the owners or administrators who are reluctant to deviate from the "standards, policies and procedures of design manuals". On the other side we have historians who cannot understand why we cannot leave the railing as is or the roadway width unchanged if there has been no incidences of accidents. Yes, we have a method called "design exceptions" where we can deviate from accepted practice, if conditions warrant but there is a hesitancy in many instances to go this route as it only takes one accident to set the legal process in motion to seek financial remedies.
We all know that a succesful project should involve the engineering people working with the historic people from the outset. I suggest there are many times when we need to bring in the legal people to gain their insight into our concerns and help us with solutions when deviations from the standards are warranted. Are they the "third leg of the stool" that is missing? We can accomplish this in the short term by inviting a few of them to these discussions. We seldom have an opportunity to hear from them.
Joe
I'm curious as to what the role of lawyers might be. Compliance with regulatory (i.e. preservation) and engineering standards--and occassional exceptions that reasonably deviate from those guidelines--seems better suited to preservation and engineering professionals. Has anyone involved lawyers in seeking exceptions to standards?
One of the keys to success in preserving our bridges (historic and otherwise) is setting objectives at the outset of the project. In other words,what is the desired outcome, and what are the measures of success?
A common default is to measure restoration and rehabilitation project results against current design codes. The desired outcome is assumed to be functionally a new bridge - one that meets all of the geometric, safety, strength, and serviceability standards of a new bridge. I say "assumed" because the criteria are not always consciously considered and developed.
A concept study should be done early on, where the key parameters and peoples expectations are set. It is in this phase of a project that the balance between budget, preservation and on-going bridge performance is established. It is not very reasonable to expect the owner or the designer to continually adjust the project objectives and the resulting effects on the budget and schedule.
There are some interesting metal bridges in the northwest where the original geometrics are accepted and reasonable standards for load-carrying capacities are set. These are successful because realistic and achievable project objectives are estabished.
Owners tend to struggle with "design exceptions". There are always corners that can be cut in new designs, and the design exception process is intended to keep designers from cutting those corners. There are lots of good reasons for this. This creates a culture where exceptions are hard to get and where designers are hesitant to apply for them.
The design standards exist primarily to keep our road system safe, even for the guy on his cell phone as he drives home from the local watering hole.
The lawyers can help the designers and the policy makers understand the limits of how far they can go with design exceptions.
Currently there is a push nationally for "practical design." This is a concept that encourages States to design projects that are just good enough, not necessarily perfect. That is fostering an environment where designers can develop projects that don't necessarily conform to all of the old design rules. This may help us with bridge restoration and rehabilitation.
The topic as posed has made me scratch my head a bit:
The rigid approaches of preservationists (as I interpret the first half) and the rigid approaches of engineers, are not so much in conflict. They are really the same thing: Rigidity of approach and adherence to rule-based decision making. For each, the rules come from their respective "standards". It is not true that the engineer is fully objective, nor is it true that the preservationist is simply making stuff up. They are both failing to recognize what is important.
"Knowing what is important" is one way of saying judgment. So for both engineers and preservationists, the lack of judgment is pretty common. I can give countless examples for both....which would be a lot of fun to do if we were sitting on the porch with some drinks.
For example, preservationists usually:
Engineers will often:
It is clear from my experience that preservationists are not really the ones stopping bridge rehabilitation. So it may make us feel good to say that they are, but I don't buy it. The professional ones especially have gotten in my way and on my nerves, and driven up the costs of things a little. But we loose good, usable, significant bridges because of engineers' narrowness and DOT policies, which prefer replacement over rehab.
I really like Abba's phrase that we need to give the owner an "excuse" to save the bridge... this seems to hit the nail on the head. The owner has to essentially go against the standard DOT and engineering approach/policy, and to do so requires an excuse. And it is our job (engineers and preservationists) to give it to them.
I thought I'd take a minute to throw my 2 cents in on this discussion.... I agree with Patrick that it isn't preservationists who are the ones to stop a project even though they are typically portrayed as the "project stoppers." In my 31+ years with the DOT I don't think that I've ever seen a single situation where preservationists stopped a project dead in its tracks on our program. They simply do not have the power of law and regulation on their side. Now, savvy preservationists can significantly slow a project's process by asking the right questions at the right time. But usually those questions will focus on an agency having forgotten or neglected to do something that is required of the agency under the NEPA/106/4(f) triumvirate, such as identifying consulting parties, conducting adequate public involvement, etc. So in my experience, project stops happen when the agency forgets something or something unexpected happens (such as a late discovery or an unexpected discovery during construction).
Certainly rigidity happens in both the agency and preservation camps, even though Sec. 106 requires a good faith effort in consultation and a negotiated outcome. So who's fault is it? Ultimately, its the fault of the lead federal agency or the agency with that delegated responsibility because that is who has ownership of the process. If the agency does all of the steps correctly through NEPA/106/4(f), then you will have an outcome that is completed pursuant with law and regulation, i.e., no predetermined outcome. An earlier post made a good point that the AASHTO guidelines for rehab vs. replacement won't work if someone tries to manipulate the process predetermine the outcome -- but that also speaks to the larger issue that the Sec 106 process won't work if someone tries to do that. I personally was glad to see that point made, because the intent of what we tried to do with those guidelines was make them tight to the regulations (I wrote the problem statement that lead to the guidelines and served on the panel).
So to wrap this up, I agree with Patrick that Abba's statement about giving a bridge owner incentive to preserve a bridge, lies more with the agency/engineers than it does on the preservationist's side. One way this may happen (and now I'm commenting on the Ken Harwood email that Terry sent out to all of us on 5/1/09) is through the green initiatives that agencys are implementing. Speaking just from the perspective of my agency, we are undergoing a wholesale revamping as a green agency under the direction of our new Director. There have been bits and pieces of green initiative thinking before, but this is a complete makeover of this agency. For example, in ODOT's Sustainability Assessment Report, the statement is made: "As far as working toward a "Better than Before" environmental policy, the more ODOT promotes reuse of historic buildings and bridges rather than demolition and removal to landfills, the more we will continue to have positive impacts on communities and the state in general in the the areas of sustainability, historic preservation, and stewardship."
This is just starting at this level with this agency, and will take time, but I think this supports Patrick's, Abba's, and a couple of other points made in this discussion thread. I would be curious to see how other state DOT's are proceeding with green initiatives. I know there's a lot of this beginning. There will still be negotiated outcomes that one side or the other won't like when it comes to historic bridges, such as how best to increase the load rating on a structure or increase capacity without compromising historic integrity. Or creating a adverse effect on a historic bridge by compromising integrity in order to re-use it. It would be interesting to see people's thoughts on challenges we'll have in trying to do some of these green initiative/sustainability approaches.
Paul Graham
Assistant Environmental Administrator
Ohio Department of Transportation