Consider it Bridge Week or Bridge Days, as the Lake Champlain Bridge center span is set for floating and lifting any day now.
Hardly any structure proves to be permanent; very few materials hold up for eternity. Concrete is a particularly troublesome material to many because moisture and salt and lack of maintenance equal a recipe for structural failure. Yes, I am referencing the 1929 Lake Champlain Bridge; but I am also thinking about the small concrete bridges across the nation. These bridges have concrete decks and concrete piers and railings, and we are losing them at an exponential rate.
Ripton, VT
Often, these small bridges face the fate of poor hydraulics or structural and geometric inadequacies; simply put, they do not meet AASHTO standards and any projects that rehab these bridges are required to bring them up to federal standards and code. But because these bridges were so ubiquitous in the middle decades of the 20th century, they are hardly significant, according to many. Some are significant for technology or design or engineering, but mostly they come across as yesterday’s steel girder, single span (i.e. boring) bridges. Furthermore, repairs to these bridges have destroyed their integrity, and with that, any eligibility for significance.
Albany, VT
However, I have recently found myself disheartened by the fate of these bridges; I love small concrete bridges with decorative concrete piers and interesting railings. Whenever I cross a new 3 bar aluminum (or worse! steel w-beam type) bridge, I wonder what it has replaced and when. Alignments have likely been straightened and a bridge with character destroyed. (Go ahead, call me a transportation preservation nerd; blame it on the day job).
Sheldon, VT
Covered bridges are adored and respected. Metal truss bridges are heading in that direction. But, concrete bridges that aren’t elaborate concrete arch bridges are often overlooked. I’m working on understanding the context and significance of small concrete bridges so I can either a) come to terms with the fate of such bridges or b) convince others of their importance. That doesn’t mean that I am the only one who thinks about concrete bridges, but I am looking for others who would like to talk about them. We can’t save everything in preservation, nor should we, but as time passes we need to reevaluate what is important, what is diminishing, what has been insignificant, and figure out what to do with these resources. How are they treated differently if they are out on a dirt road in the middle of nowhere v. in a historic district. (Okay, that’s probably an easy answer, but what if the concrete is indicative of the landscape and a certain era of road travel?)
Wheelock, VT
What are your thoughts on small concrete bridges? For now, I’m still pondering and gathering any historical context I can find.
Preservation in Pink 
Kaitlin,
I am currently working on a large statewide bridge survey and have been evaluating bridges along the lines that you mentioned. The concrete slab bridges with pierced parapets are ubiquitous, but there’s something about seeing an intact single span concrete slab bridge with a concrete parapet in a rural setting that makes you appreciate its integrity. The bridge didn’t suffer having its parapets replaced by guardrails or its substructure receiving repairs that were not in-kind. Or why is there a cluster of intact small single span bridges along the same creek? It makes you wonder what transportation project was involved and if it’s significant. Within the survey, we’re also evaluating the large amount of 1950s and 60s steel girders that exist. Again, you have to enjoy and educate yourself about the small elements that make each bridge different- the builder, decorative treatments, the pins, bolts, or welding joints.
We also are working on a more critical analysis of concrete bridges that have distinguishing builder marks compared to the more standard designs. We’re also establishing associations with various historic contexts under Criterion A . Maybe you can research on establishing a context on how the concrete slabs were developed in your state. Contexts like the New Deal or various transportation legislation that aided highway improvements. AASHTO does have a good site that lists links to various statewide bridge surveys that might be helpful.
I also can’t seem to get away from bridges- I went away for a long weekend in the Poconos and my friends and I went and saw the Roebling Bridge. I think Mary Wash needs to set up a class on bridge styles, because it seems that some of their graduates have been working on more bridge projects than historic building projects! : )
I, too, notice bridges. I grew up in Michigan before “Big Mac, the span that now connects the two peninsulas of Michigan. Your post made me think of a charming concrete bridge here in Newberry, SC, a nice arched one over a railroad track. It has very attractive lampposts and seems intact. I think I’ll see how old it is and maybe it’s one we can save. Newberry is doing a nice job on preservation over the past 15 years. Before that, not so much.
The first step in preserving concrete bridges will be to convince the public that they’re worth saving even though they’re not easily conserved and often do not meet modern needs. It’s interesting that you mention the increased appreciation of steel truss bridges- I think that people are beginning to notice them (just as they did with covered bridges) as they disappear from the landscape.
It may be more difficult to build a constituency for concrete bridges. Because most don’t have a truss system or other vertical elements (beyond maybe a decorative rail) that rise above the deck, most people don’t really notice them as they pass over. Many of the remaining concrete bridges are also low in the landscape over small crossings so people aren’t as likely to see an arch or other fine details below the deck level.
I do think it’s possible for people to realize that concrete bridges (particularly concrete arches) can be elegant and interesting. All we need is a half-century of evocative landscape photos published in Vermont Life!
I have recently looked into a 1912 single-arch reinforced concrete bridge in Yankton South Dakota. It went through some upgrading in the 1980s including a stucco-esque coating, but was still considered eligible and listed in 2000. It was interesting to see that the historic concrete used huge chunks of local quartzite stone. Pic of the current condition of the “Pine Street Bridge” on wikipedia under “List of bridges on the National Register of Historic Places in South Dakota”
Background research yielded some great studies of bridges and guidelines for rehab in addition to the Preservation Brief #15. Search: Ohio DOT “Ohio Historic Bridge Maintenance & Preservation Guidance”; and University of Wisconsin-Madison “Rehabilitation techniques for concrete bridges” but there was a lot more too. It was great information to pass along to those actually planning the rehab locally who were luckily willing to do preservation right.
Also a nice tie-in for a historic context argument might be to local “good roads” movements.