The fifth and final part of the series on Erfurt’s historic bridges deals with the interview with the authors of the book, Hans-Joerg Vockrodt and Dietrich Baumbach. The interview took place this past June, and after going through the dialogue and translating it from German to English, I managed to present the interview in a way where everyone can benefit from reading it. There were a lot of discussion not only about their books, but also bridge preservation and the development of transportation to date and how it has had an effect on the bridges in Germany and the US. This will set the stage for another article coming in the next day(s) dealing with the five-year anniversary of the Minneapolis Bridge disaster. So without further ado, here is the transcript of the interview that took place at one of the small cafés in Erfurt:
Dietrich Baumbach received a Diploma degree in engineering and worked at the city administration office in Erfurt in the infrastructural section. He is now retired. Hans-Joerg Vockrodt received his degree in civil engineering at the Bauhaus University in Weimar (east of Erfurt). He works at a planning office in Erfurt, specializing in bridge building and restoration, the latter of which he has been doing for over 20 years.
Smith: How did you become interested in historic bridges?
Baumbach: After the German Reunification in 1990, there were a lot of bridges that desperately needed to be rehabilitated to keep it from deteriorating to a point where they were no longer safe and this is where our interest started, even though it was outside our working hours.
Vockrodt: In connection with the historic bridges in Erfurt, there were many bridges that needed to be rehabilitated and this started with the Kraemerbruecke in 1998/99 and continued with other bridges, such as the Radowitz and Kraempfertor Bridges. As the bridges were being restored, the interest in not only the restoration of the structures (restoring it to its original form) but also the history of the bridges grew over time.
Smith: How did the Preservation Laws influence the preservation of bridges before 1989? (Note: The preservation laws existed both in East as well as in West Germany between 1949 and 1990 when the countries and their policies were integrated into one)
Baumbach: Preservation Laws existed in East Germany but the problem we had was the lack of money and resources that were available for renovating and maintaining the bridges. The Kraemerbruecke was renovated because it was one of two main attractions for the city (the other being the cathedral Erfurter Dom) and therefore, it was important to make it attractive for the tourists. (Author’s note: The bridge was renovated twice during the Cold War with extensive work being done in 1986, where the stone arches were redone.) Yet after the German Reunification in 1990, the process of repairing and restoring historic bridges began in full force.
Vockrodt: Preservation laws during that time was focused mainly on the high-rise buildings that existed in the 1980s. So instead of tearing down historic buildings in place of these building blocks, the historic buildings were gutted out, meaning the inner part was replaced while keeping the façade of the outer part intact. This was done with a pilot project in the city center of Gotha (west of Erfurt) in the mid-1980s, and it later extended to the historic bridges and other buildings.
Smith: So the problem you had similar to what we have in the States today, where lack of funding and resources (expertise) resulted in many historic structures being demolished and replaced. Do you see that today with the historic bridges?
Baumbach: One cannot preserve all the bridges as we have to take in account the significance of each structure compared to the high vehicular demand and the tension exerted on the structure by crossing it. In some cases, these bridges need to be replaced with heavier and wider structures. One could make a historic bridge (in particular deck arch bridges) wider to accommodate traffic, but this comes at the cost of its historic significance- most of the time it is compromised.
Vockrodt: There is also the phenomenon where a historic bridge can be duplicated so that it serves a dual function of being a historic bridge and one that carries large volumes of vehicles. An example of how a bridge can be duplicated is an arch bridge located in Saxonburg (located near the Thuringia/ Hesse border northwest of Meiningen). It is an arch bridge that was duplicated because of its historic significance and it was part of the project supported by the State Department of Historic Preservation. Despite the fact that it accommodated four lanes of traffic, its historic significance remained the same. We’re seeing that with other bridges in Thuringia (and elsewhere) where the increase in the volume of traffic has warranted the need for bridges that are sturdier and wider. For other historic bridges, like the Kraempfertor Bridge, the bridge needed to be wider to accommodate not only four lanes of vehicular traffic, but also two street car tracks. We were lucky that we were able to secure financial support for the project where the bridge was widened but the historic appearance remained the same.
Most of the bridges built/rebuilt nowadays are those that carry main highways and serve regional areas, including the Autobahn (German Motorways), where the majority of them are built in the 1950s (in the western half) and the 1930s (in the former East Germany). These bridges are being replaced because they deteriorated greatly as a result of increased traffic load. These bridges are usually not recognized as historically significant and are not protected by preservation laws, only those located in cities with a historic setting and whose population is interested in them are the ones that receive the attention.
It is the same with the USA, where it is unthinkable to tear down the Brooklyn Bridge in New York because of that interest. (Note: John Augustus Roebling, the bridge builder and inventor of the wire-cable suspension bridge was born in Muhlhausen in northwestern Thuringia)
Baumbach: Another bridge worth noting is the Lehmann Bridge in Erfurt (one of the oldest arch bridges in the city). In the 1970s, the bridge was in such a desolate state that it had to be demolished. That was the mentality of East Germans (at that time) because of the lack of resources needed to rebuild the bridge, let alone to repair the bridge. After the Reunification of 1990, it would never have been dreamt of because the Preservation Laws (today) have a higher meaning and more interest.
Vockrodt: This mentality (of tearing down old structures and building anew) was also found in the western part of Germany in the 1950s, and as a result we see “modern” cities like Frankfurt (Main) and Kassel (both in the state of Hesse). However this modernization has nothing to do with the lack of resources that we had here in the eastern part of the country.
Note: Most of the bridges in the western part of Germany were built in the 1950s and mostly consisted of bland beam bridges with little historic value. This can be seen clearly in cities, like Frankfurt (Main), Mannheim, Stuttgart, and cities in the Ruhr River region (in North Rhein-Westphalia).
Smith: Apart from the two books you wrote on Erfurt’s bridges, what other pieces of work did you write about the bridges?
Vockrodt: My first work was published in 1995. Since then, over 20 literary pieces on this subject were published, much of which were in connection with stone arch bridges, bridge preservation in Erfurt, etc.
Smith: Going to the two books you wrote on the subject of Erfurt’s historic bridges: What is the difference between the two?
Baumbach: The first book (published in 2000) focuses on 12 arch bridges and its technical details (including the history of its construction, the rehabilitation and the materials used for bridge (re-)construction. The second book (published in December 2011) deals with the historical aspect, especially of the bridges that no longer exist (like the Lehmann Bridge and those along the Wild Gera before it was rechanneled).
Vockrodt: The book also features technical drawings and details of each of the 12 bridges that exist, whereas in the second book, it is integrated into the historical context.
Baumbach: Especially in the first book we dealt with the bridges based on our expertise from our own areas of interest (me as city administrator and Vockrodt as civil engineer) and our goal was how to bring these bridges to the interest of the people in Erfurt. This is also in connection with the plan to nominate the historic bridges in Erfurt into the Preservation List in 2000 (Note: In German it is called Denkmalschutzbuch, which is similar to listing the historic places on the National Register of Historic Places in the US).
Note: The reason for choosing stone and concrete arch bridges in the first book was two-fold: 1. These bridges were mostly used for construction- over 30 of them were found within the city limits of Erfurt and 2. These 12 inner-city bridges were the focus of restoration which took place on all but one of them. That bridge (the Karlsbruecke) will be next for rehabilitation as early as next year. Also worth noting is by including every single bridge in the first book would result in the loss of interest and therefore, the ones not mentioned were put in the second book with one exception: the railroad bridges were mentioned in another book on the railroads of the Greater Erfurt Area (Germ.: Eisenbahndirektion Erfurt) published in 1994 but still in stock.
Smith: Did you have any difficulties finding any information on the bridges, for some of it may have disappeared because of World War II and the regime of the Socialist Party that followed in East Germany?
Baumbach: There were no problems finding the information as much of the information from the Cold War period were given to the Federal Republic at the time of the Reunification but remained in the archives.
Vockrodt: Apart from the archives, what also helped was designing the bridges as it was and providing the details of the structure. It was first done by my father (who was also an engineer) before I took over.
Smith: Did you use oral resources for the books? (Note: Oral resources means asking people about the bridges and finding out more information about their history from their point of view. This is useful when writing about the history about a topic, although in cases like historic bridges, many of these sources are dying off in mass numbers, and one has to make do with the people who have no connection with the construction of the bridge but have knowledge and collections of them).
Vockrodt: The only source that is closest is the city archives in Erfurt. There we did a lot of research into the bridges by finding old photographs, paintings and drawings but also finding other sources of information that was useful for the book. The person at the city archives was more than helpful in providing us with as much help as possible. Otherwise finding the information and the people willing to help is really difficult.
Baumbach: There are some people who had collections of postcards of bridges and were willing to let us use them. Other than that, who do you ask if the people who built them are long since gone and you have to make do with the ones who know about the bridges?
Smith: Here is an engineering-related question for you: Since 1985 the number of historic bridges built before 1945 have been replaced with modern structures. Can you summarize the reason for this change?
Vockrodt: One of the reasons is the increase in traffic both in numbers and size, which makes these bridges obsolete. The other reason is in the last century, we have seen an increase in the weight of the vehicles beginning with the horse and buggy, followed by the car, the train, the semi truck and the heavy goods transporter. The deciding factor is the increase in traffic volume which has a negative effect on the bridges that were built in 1945 and earlier because they lack the material needed to accommodate these increasing loads. Other factors include the rust and corrosion of steel caused by salt and other chemicals combined with the lack of maintenance, meaning repairing the bridge every 10 years. Many bridges that have structural issues are inspected every four years with some being inspected annually, but some of the bridges that are in so poor shape are replaced as rehabilitating them would be impossible. This applies not only to pre-1945 bridges but also bridges built in the 1980s, where the increase in traffic loads have caused a strain in the structure itself to a point where even these bridges have to be replaced.
Smith: Now that you mentioned steel corrosion, let’s look at one of the steel bridges, the Riethstrasse Bridge, where weight and height restrictions are now in place. Why is that?
Baumbach: The reason for these restrictions is the fact that many trucks have travelled across the bridge without regard to the weight limit. I have witnessed this myself. Therefore it is necessary that these restrictions are in place so that only cars can travel across them.
Vockrodt: The restriction is basically the decrease in the vehicle’s geometric dimensions and with that, the decrease in the weight.
Smith: Will this bridge be replaced or restored soon?
Baumbach: It depends on the number of vehicles crossing it. If the number of vehicles crossing it is minimal (and the bridge is on a less travelled street), then the bridge will remain in service in its usual form. Yet if the street is extended to include a suburb and traffic increases as a result, then it will have to be replaced. The bridge would have to be saved as it is protected by Preservation Law and would have to be restored and reused for other purposes apart from a pedestrian bridge.
Note: The Riethstrasse Bridge carries minimal traffic through a residential area in the north of Erfurt. It’s neighboring bridge 0.4 kilometers to the north, the Mainzer Strasse Bridge (built in the 1980s), carries a throughway route to Rieth, the shopping area, and the Albert Schweizer Gymnasium (high school). Both will be replaced in 2019 but the former will be kept and reused as a historical monument.
Smith: Since you are on the same page with the Preservation Laws, how has that changed between the era before 1989 and after 1990?
Vockrodt: Nothing has really changed as the Preservation Laws are incorporated in the state laws, which states that any building or structure that has historical and cultural value, and whose interest is high in preserving it is protected by law. The owners are required to preserve it in its original form.
Baumbach: The only problem with this is the financial aspect. Money is needed to restore these structures and the resources are limited. In some cases, like with bridges, it costs more to restore and preserve than to replace it outright. Yet it is possible and an obligatory to keep to the laws that exist. Delisting a structure is possible if the structure is slated for demolition and there are no alternatives to rehabilitating them.
Vockrodt: Yet in some cases it is necessary to build a new bridge instead of keeping the old one if the traffic demand warrants it.
Note: This reminds me of a couple of bridges along the Baltic-North Sea Canal that were built in the 1880s- the Grünental and the Levansau Bridges. Both were protected by the preservation laws in Schleswig Holstein, but the former was delisted when it was demolished in the 1990s because of severe structural deterioration. The latter is being replaced as the canal is to be widened and the length of the bridge is an impediment to the ships passing underneath it. It will eventually be delisted once the demolition is completed by 2023.
Smith: How big of an interest do the people have in bridges in general?
Baumbach: The interest in the bridges are there, especially when we saw the number of people that saw our presentation on the 27th of May. Many of them know about the book. Yet, when looking at it locally, the bridges are in the backburner, as the churches, towers and renaissance buildings far outweigh them in their importance. Many people know about the Kraemerbruecke but they don’t know the other bridges, let alone they don’t know that they are crossing a bridge in the city.
Vockrodt: That is the reason why we wanted to bring the bridges to their attention. While Hamburg and Nuremberg have many gorgeous historic bridges, we wanted to present Erfurt’s historic to the attention of the public. That was our motivation behind writing these books.
Smith: Is this phenomenon, the lack of interest in bridges, in connection with the I-35W Bridge Disaster in Minneapolis (USA) on 2 August 2007?
Vockrodt: No, that is not the role. The bridges are inspected regularly for structural deficiencies. The agencies have done a great job in inspecting the structure and its surroundings and therefore have not seen any bridge disasters here in Germany, let alone the northern part of Europe. That’s why people take bridges for granted and concentrate more on other places of interests, like churches for example.
Smith: Which historic bridge is your favorite bridge (apart from the Kraemerbruecke)?
Vockrodt: Good question. I’ll stick to that bridge.
Baumbach: Mine is the Wilhelmsteg Pedestrian Bridge in the south of Erfurt because of its sleek design and its proximity to another favorite: the Pfoertchenbruecke.
Smith: Which bridge did you find the most interesting in terms of its history and bridge design?
Vockrodt: The Kraemerbruecke in terms of its history, for it goes back several hundreds of years and as far as design is concerned, the Wilhelmsteg because it is the thinnest arch bridge in Erfurt plus the ornamental design in the arches that exist. (Two bridges in Erfurt have similar designs in the arches: that and the Karlsbruecke)
Baumbach: I agree with him.
Smith: Which bridge did you find the most amount of information about (Apart from the Kraemerbruecke)?
Baumbach: All the bridges along the Flutgraben because of the articles and descriptions that were found in our research.
Smith: And the most difficult? Those over the Wild Gera before they were removed and the river was rerouted?
Baumbach: That is true. We had to rely on paintings and pictures as there was seldom articles about it and if so, it was written in old German, which is different from the Latin letters that we are used to.
Vockrodt: There were no plans for the bridges and we had to rely on images to help us.
Smith: Will you be continuing your research and book writing in the field of historic bridges?
Vockrodt: We would like to stick to the topic as Thuringia has lots of bridges which we would like to inquire about
Baumbach: We would like to go outside the city and have a look at the bridges that exist elsewhere.
Smith: Are there any plans to have them translated into other languages, like English or French?
Baumbach: It depends on the interest….
Vockrodt: …..both on the people but also the publisher. At the moment the interest is low and the publishers we use (which are in Erfurt) are not interested in having the books translated yet. But we’ll have to see if that changes. (Note: Both books are in German).
Smith: If there is someone who is interested in writing a book on historic bridges, what advice would you give to that person?
Vockrodt: Research on the historical aspect is important although difficult to research. If you eye a bridge, you need to look through the sources to see how much has been written about it so that you can use it and add your information to it. Also important is finding a publisher who will sponsor this project. When you have a partner, then you can proceed with the project. Our publishers were with the organization that deals with Erfurt’s historic bridges and they were most supportive of this project.
Smith: So more information and support?
Baumbach: Yes. Once you have a sponsor, you may have to think of making a deposit of EUR 5000 ($5600) so that it has some security should the sale of books be poor. It is really difficult publishing a book these days.
Vockrodt: The most important thing is you have to have the people on your side that are interested in this topic, and we found that the interest has increased since our second book has been published and even more so as we present our topic.
Smith: Ok, that’s about it. Thank you for your time and I wish you the best of luck in your future endeavors with this project.