Interview with Denis Gardner

Robert Street Bridge (foreground), the St. Paul Vertical Lift Bridge (middle) and the Wabasha Street Bridge (background) all spanning the Mississippi River in St. Paul. Photo taken in August 2011

 

 

Some of us have a sixth sense- when one senses something that will happen in the future in the present and take action to avoid it. Some of us see something that happened and takes measures to save face and avoid further trouble. In this case, it is the latter. Yesterday, I posted the Book of the Month column on Denis Gardner’s book, “Wood, Concrete, Stone and Steel: Minnesota’s Historic Bridges,” encouraging people to read the literature. Early this morning, I received the interview questions from author Denis Gardner himself, which I sent prior to my vacation in Schleswig Holstein two weeks earlier. Contrary to what I wrote about his work, Gardner provides a few answers to my questions from his own point of view, which includes a hint that a book on the history of bridge builders in Minnesota should be on the “To do” List for any author wanting to tackle this project. 

Without further ado, here is the interview with the author:

1. BACKGROUND INFORMATION (A SHORT SUMMARY OF YOUR OCCUPATION AND BACKGROUND IN HISTORY):

My B.A. is in history. And, not surprisingly, I never thought I would end up in an occupation with history at its core, but sometimes we get lucky. I also have a Master of Liberal Studies degree.

I was fortunate enough to be hired by a historical consulting firm in Minneapolis that specialized in studying buildings and structures. In other words, the firm frequently was hired by governmental agencies and others to complete studies in areas with cultural resources (buildings, structures, etc.) that may be impacted by a project. For example, if the Minnesota Department of Transportation was completing a road project through a particular community, our firm may be contracted to study the area to determine if there were any historic buildings or structures in the area that may be impacted by the project. Such a study stems from the Historic Preservation Act of 1966, a section of which requires agencies receiving federal funding or federal licensing to discover if their projects negatively affect any properties believed historic—that is, any properties listed in the National Register of Historic Places or any properties eligible for listing in the National Register of Historic Places.

Initially, I began working as a researcher for the firm. Over time my role expanded to include surveying and writing as well. Eventually, I wrote many studies on various building and structure types. I also wrote two books that cover these subjects. The first book was Minnesota Treasures: Stories Behind the State’s Historic Places (Minnesota Historical Society Press, 2004) and the second was Wood, Concrete, Stone, and Steel: Minnesota’s Historic Bridges (University of Minnesota Press, 2008). In late 2011, I became the National Register Historian in Minnesota, replacing Susan Roth, who retired after occupying the position for many years.

2. WHAT IS YOUR FAVORITE TYPE OF HISTORY THAT YOU ENJOY WRITING AND/OR VISITING? (BRIDGES, WARS, NATIVE AMERICAN, BUILDINGS, OR OTHERS)

It is difficult for me to pick only one type of history as a favorite. I find the subject of history in general fascinating, and I will read just about any historical subject. The field within which I work, however, is that of the built environment (buildings, structures, objects, districts, and sites). My work is intimately tied to the National Register of Historic Places. As a result, much of my reading surrounds this subject. My visits are often to buildings/structures that are either in the National Register or are being considered for listing in the National Register. Still, I enjoy a wide variety of historical subjects and read and visit other things as well when I have the opportunity.

3. HOW DID YOU BECOME INTERESTED IN HISTORIC BRIDGES?

I became interested in bridges many years ago when I began working in the field of architectural history/historic preservation. When I was hired as a researcher for the Minneapolis historical consulting company, the firm was in the middle of completing a statewide bridge survey. The survey came about because the Minnesota Department of Transportation needed to know which bridges on Minnesota roadways were eligible for listing in the National Register. For Mn/DOT, knowing this allowed the agency to plan ahead, to recognize in advance which bridges were historic via National Register standards and which ones were not. During my first six months at the consulting company I spent every other week on the road traveling about the state, visiting county and state highway departments, local historical societies and libraries, county courthouses, and wherever else research on bridges guided me. I became quite fond of bridges.
4. YOU MENTIONED IN YOUR BOOK THAT THERE WERE TWO OTHER HISTORIANS (ROISE AND HESS) WHO WANTED TO WRITE ABOUT MINNESOTA’S HISTORIC BRIDGES BUT DECIDED AGAINST IT BECAUSE OF CONFLICTS. WHY DID YOU DECIDE TO PURSUE THIS PROJECT? WHAT WERE YOUR MOTIVES?

In truth, there is another historian that I thought might write the book, Robert Frame III. Frame, like Jeffrey Hess and Charlene Roise, was one of the first to study Minnesota’s bridging history in depth.

Author’s Note: Frame wrote at least three reports on historic bridges in Minnesota including a comprehensive report in 1985 which focused on all bridges built prior to World War II, most of them being metal truss bridges whose history was brought to the interest of many people working with historic bridge preservation.

After completing my first book, and concluding that someone else was probably not going to write a Minnesota bridge book anytime soon, I decided that I would write it. Doing it almost immediately after the first book seemed a good idea since I was still in the book-writing mode—I thought that if I did not do it then, I may never get to it.

??5. IT IS SOMETIMES UNUSUAL FOR FAMILY MEMBERS TO BE INVOLVED IN A BRIDGE PROJECT. WHY WERE YOUR MOTHER AND BROTHER INVOLVED?

My mother was only involved to the extent that she liked traveling around and seeing things. So, when I was completing the photography on bridges—running around the state—she often was a companion. Like myself, my brother enjoys photography. As it was going to be difficult for me to get all of the bridges photographed in the allotted time period, I asked if he would be interested in completing some of the photography.
?6. WHY DID YOU STRUCTURE THE BOOK THE WAY YOU DID- BASED ON THE MATERIALS USED AND IN CHRONOLOGICAL ORDER?

Simply put, it seemed the logical way to parcel the book. Bridges evolved largely according to the material used to build them—wood and stone bridges came first, then metal bridges (first iron and then steel), and then reinforced-concrete bridges. By dividing the book in this way I could provide a mostly chronological history.

7. HOW DID THE USAGE OF MATERIALS INFLUENCE THE DEVELOPMENT OF BRIDGE TYPES (TRUSS, SUSPENSION, ETC.)?

Wood bridges always suffer from the fact that wood does not last as long as other materials. As a result, wood bridges are frequently replaced with bridges made from another material. Stone bridges may last a very long time, but are exceedingly expensive and labor intensive. It is extremely doubtful that we will ever see another large stone arch bridge. We may never see another small one, at least in Minnesota.

Metal and reinforced-concrete provided engineers with flexibility. Metal truss bridges supported substantial loads and yet their members (diagonals, verticals, etc.) did not need to be nearly as large and cumbersome as the members for wood bridges. And again, metal bridges generally lasted longer than wood bridges.

As concrete is relatively plastic, this allowed bridge builders to shape bridges, perhaps adding an aesthetic to them that was not available with previous materials. Concrete is very strong in compression but rather weak in tension, so metal reinforcing was introduced into the concrete to ameliorate this problem. All manner of bridges have been built with reinforced concrete: slabs, girders, arches, culverts. With reinforced-concrete a monumental arch bridge could be erected without the labor and expense that comes with building an arch made of stone. The material is so versatile that I don’t envision it falling from favor anytime soon.

As for suspension bridges—I am hardly an expert, but it appears that these have typically been made from metal, although concrete may sometimes encase metal. For example, the girders beneath the deck of the Hennepin Avenue Bridge are steel girders. However, the towers, from which the cables descend that carry the deck, are made of reinforced concrete. Concrete allowed engineers to shape the towers relatively easily into a pleasing form. Very large suspension bridges (such as the Golden Gate) are acted upon by terrific forces. The gales blowing through the bay would likely wreak havoc on bridge reinforced-concrete members that were employed in areas of great tensile stress. I assume that such members would begin to wear and crack in a short period of time.

8. WHEN THE 28 BRIDGE BUILDERS CONSOLIDATED TO CREATE THE AMERICAN BRIDGE COMPANY, THE BRIDGE BUILDERS FROM MINNEAPOLIS (SPECIFICALLY, THE DYNASTIES OF HEWETT, JONES AND BAYNE) FILLED IN THE VACUUM AND BECAME THE COUNTERPART TO AMBC. HOW INFLUENTIAL WERE THEY IN MINNESOTA AND BEYOND IN COMPARISON WITH AMBC?

I hate to admit it, but I cannot truly answer this question. As I note immediately below, we need someone to write the book on Minnesota’s bridge builders. With my bridge book, the focus was chiefly on the bridges themselves. There was discussion of bridge builders, certainly, but it was mostly peripheral to the bridges. The question that you raise is an interesting one, but I simply cannot answer it with confidence. We need more information on the builders.

9. ANOTHER BRIDGE BUILDER, LAWRENCE JOHNSON WAS AN IMMIGRANT FROM FLENSBURG IN PRUSSIA (NOW SCHLESWIG-HOLSTEIN GERMANY). HOW INFLUENTIAL WAS HE AND IN YOUR OPINION, WHAT CAUSED HIM TO GO INTO POLITICS? (NOTE: IT IS RARE FOR BRIDGE BUILDERS TO BECOME POLITICIANS, OR IS IT?)

Similar to my comment above, I don’t think that I can do justice to this question. I have always felt that the early bridge builders in the Upper Midwest deserved an entire book. We know so little about them, yet they built so much of our infrastructure. Fredric Quivik penned “Montana’s Minneapolis Bridge Builders,” which offers more history on area bridge builders in one source than just about any other source. My assumption is that Johnson was influential, for he was one of these early bridge builders—in truth, it was a rather small fraternity. Am I surprised that he became part of the Minnesota legislature for a spell? Not really. Early Minnesota was littered with personalities that were prominent within their field of expertise. Many of these individuals transferred their skills to politics—at least for a time. It was not uncommon for prominent men within a relatively new community to become representatives in the state legislature. I’m assuming Johnson was a prominent personality within the community or region that he lived. We would know for certain once someone takes on the task of penning a book on Minnesota’s early bridge builders.

Author’s Note: The information in the book was only meant to scratch the surface as focusing on the tiniest aspects of the bridge engineers would warrant not only a book on Minnesota’s bridge builders, but also on the dynasties themselves, like the Hewetts, for example.

10. HOW HAS THE I-35W BRIDGE DISASTER OF 1 AUGUST 2007 INFLUENCED THE WAY WE THINK OF BRIDGES AND INFRASTRUCTURE IN GENERAL?

I think that it has made us more aware of bridges, and perhaps it has made us worry more about bridges. This worry is sometimes warranted, since many bridges are exhibiting wear, sometimes substantial wear. Bridges can last a long time, but like anything else they need regular maintenance. I don’t think most people defer maintenance on their houses for years, yet it seems that some of our bridges have been left to wither. I don’t think we can necessarily blame the counties for this (the counties oversee most, but not all, of the bridges in Minnesota). If the counties do not have the money to complete required maintenance, it is difficult to place blame at their door. The state highway department may be in a similar predicament with some of its bridges. The simple fact is that we need funds to take care of our bridges—indeed, to take care of our infrastructure as a whole, as it is plainly suffering.

An example of a bridge that is in disarray: the Lafayette Bridge over the Mississippi River carrying US Hwy. 52 in St. Paul. Built in 1968, the bridge will be replaced in 2013 and demolished as a lack of maintenance combined to rust and corrosion have lead to its untimely doom. Photo taken in August 2011

?11. AND WHAT ABOUT THE HISTORIC BRIDGES? MANY OF THEM HAVE BEEN REPLACED SINCE THAT TIME CREATING THE DISTINCTION THAT THEY WILL BECOME EXTINCT IN 20 YEARS.

This has long been a topic that has bothered preservationist. The convention in Minnesota has been that the Minnesota Department of Transportation (in other words, the state) will take care of its historic bridges; it will do its best to do right by those bridges it oversees that have been determined eligible for the National Register of Historic Places. However, it has been left to the counties to decide what each will do with its bridges that have been determined eligible for listing in the National Register. The general consensus among those familiar with the topic is that the counties have not been anxious to preserve these bridges. To Mn/DOT’s credit it created a bridge preservation plan, which it distributed to the counties in hopes that it would spur counties to preserve historic bridges. My sense, however, is that it has not been all that successful.

12. DO YOU THINK THE STATE AND FEDERAL GOVERNMENTS ARE DOING A GOOD JOB IN ADDRESSING THE ISSUE OF STRUCTURALLY DEFICIENT BRIDGES?

The simple answer is “No.” As I noted above, our infrastructure is suffering. Money, of course, solves the problem, but we just don’t have the funds to take care of everything we would like. Again, a bridge can last for a very long time but, like anything else, it must be maintained, and that takes dollars.

??13. WHAT WOULD YOU LIKE TO SEE MORE OF WITH REGARDS TO HISTORIC BRIDGES AND PRESERVING THEM?

I would like to see the counties preserve more bridges. The counties have oversight over the vast majority of bridges in Minnesota. Regrettably, the counties often view older bridges (some may even be historic via National Register standards) as something of a nuisance. I welcome Mn/DOT’s bridge preservation inclinations, but I wish those notions would filter down to the counties. Again, if the counties had more money to maintain their bridges, preservation would likely be more of a focus.

Old Barn Bridge over Root River north of Preston. Built in 1914 by Lawrence Johnson, the bridge was closed to traffic in 2011 and its future is in doubt. Photo taken in October 2005

14. WHAT IS YOUR FAVORITE BRIDGE IN MINNESOTA? THE US? INTERNATIONALLY?

This is a difficult question. I really like the stone arch Point Douglas-St. Louis River Road Bridge in Stillwater. It is the oldest bridge in Minnesota that we have found, although we are not precisely sure how old—perhaps early 1860s, or maybe even 1850s. It is in rough shape at the moment. I also like Split Rock Bridge in Pipestone County. It is the last stone arch to be built in Minnesota (1938). It was a Works Progress Administration Project that used pink Sioux quartzite to shape the bridge. But I also need to acknowledge the Soo Line High Bridge. Frankly, it is one of the most impressive arch bridges in Minnesota, but few ever see it because it is hidden in the St. Croix River Valley north of Stillwater. It is a huge open-spandrel, steel arch built by the Soo Line Railway. Besides looking rather elegant, its engineering is fascinating. It is a three-hinged arch (which means it is not terribly rigid) but it becomes a two-hinged arch when a load passes over the bridge (in other words, it becomes more rigid).

Nationally, I like the Leonard P. Zakim Bunker Hill Memorial Bridge in Boston. It is relatively new and it is a big cable-stayed bridge. We don’t have a roadway bridge in Minnesota like this, which is probably one reason I like it—it is novel. Also, its aesthetic is impressive, and the aesthetic is a product of the engineering. In other words, we get this wonderful impression of sails, but the sails come about simply because that is how a cable-stayed bridge is put together.

There are many notable bridges around the world, but I have always been greatly impressed by the Forth Bridge over the Firth of Forth in Scotland. It is located in an unforgiving location and it is so monumental. It almost looks as if it could stand forever. For me, it resembles three Apatosaurus dinosaurs nose to tail.

 

15. IF YOU HAVE A WORD OF ADVICE TO ANYONE WANTING TO WRITE A BOOK ON HISTORIC BRIDGES, WHAT WOULD YOU GIVE THEM? WHAT WAS YOUR EXPERIENCE WITH THE PROJECT?

Studying bridges is very much like studying other types of structures in the sense that you must thoroughly enjoy history and welcome researching for hours on end. But I also would add that if one does not appreciate technology/engineering, then one probably should not be writing a history on bridges, as these things are central to in-depth study of the resource. Of course, if one was penning a bridge book that was largely literary, perhaps even romantic, that is somewhat different.

15a. WHAT WAS THE ROLE OF ERIC DELONY WITH THE BOOK?

Eric was kind enough to write the Afterword for the book. Eric has years of experience with bridges. He was chief of the Historic American Engineering Record (HAER) program for years. As a result, he is very familiar with engineering subjects, especially bridges. I was grateful that he was willing to offer his bridge knowledge to the book on Minnesota bridges.

16. DO YOU HAVE ANY FUTURE PLANS REGARDING WRITING BOOKS (ON BRIDGES)?

I would not be surprised if I wrote another book or two, although I am not sure if they will be on bridges. A few years back I was approached about doing another bridge book, but one that looks at bridges beyond the state of Minnesota. The idea is interesting, but I have not pursued it. Committing to a book is committing to a lot of time and work. I will always be fascinated by bridges, of course, but at the same time there are other subjects I would like to study and write about.
Also, I found the directory of the existing historic bridges in MN to be very helpful. Could you summarize why you did that and would you recommend any author doing that?

It seemed like a commonsense thing to do. My feeling, and my publishers feeling, was that readers naturally would like to know what other historic bridges are out there. Providing the appendix gives readers a guide to the other Minnesota historic bridges (by “historic,” I mean bridges that are in the National Register of Historic Places or bridges that are eligible for listing in the National Register). And yes, I think it a good idea to include such information in books like this. Whenever we address subjects of tangible things like buildings, bridges, grain elevators, etc.—it is a courtesy to give others an idea of what else may be worth exploring.

THANK YOU FOR YOUR TIME.

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