The stone arch bridges of the 1800s Dec 27, 2022 7:30:45 GMT -5 rickb, Peruano, and 9 more like this
Post by geoff59 on Dec 27, 2022 7:30:45 GMT -5
I live close to the tiny village of East Washington, New Hampshire; which is about as out in the boonies as it sounds. There isn’t much around here, except for tracts of new growth forests. Very close by is the town of Hillsborough, I guess you’d call it a typical, post-mill era New Hampshire town. There is as much local history around this part of the world as you could want, I guess the same is true for most places. In this part of New England, at a couple of times long ago now, many immigrants were arriving from places like Scotland and Ireland, and some of these folks brought with them what you could only call multi-generational expertise in stone masonry and craftsmanship.
In Hillsborough (often shortened to Hillsboro, either spelling is legit) and some surrounding towns have these amazing, stone arch bridges. Most of them are still in use, although there are fairly light weight-limits put on them, 3-4 tons. Everyone thinks of covered bridges made out of wood when you think about bridges and New England, but these stone arch bridges stand out from the rest, IMO. Most of them are single arches, crossing over the small brooks/creeks that are all around us, but some of them are double arch spans. The first 2 images above, they were taken underneath one of the single-arch examples along a nearby dirt road.
Each of these bridges was carefully constructed in the days before any power tools, which in itself is amazing. Each block of wood was carefully cut and shaped to pretty exacting dimensions, with the top surfaces being slightly larger in area than the bottom edges. There is NO MORTAR, no cement, no bonding agents, nothing but blocks of granite; with the force of gravity alone keeping these bridges firmly in place. I don’t think anyone alive knows exactly how the men who built these bridges did it (I’ve heard varying versions of what is and isn’t known), but I personally want to know: how did they go home for the night, leaving a partially-constructed bridge hanging over the stream, in mid air? What sort of forms or bracing did they use?
I have heard that there is going to be a project soon, where the State is planning on taking one of these bridges apart very carefully, documenting and cataloging each block of granite in the hopes of understanding how they were made. I wonder if this will actually happen or not?
These bridges are true, masterpieces of the craftsmanship of times past. A few of these bridges in the general area have been rebuilt, with modern cement used to glue them together, umm….yeah. I won’t tell you how that makes me react!
The bridge in the photo above with the flowing water, that one is in a bordering town, it’s the old bridge along State Route 9, and so needless to say it is no longer in use. I don’t think because it’s unsafe, rather because of the weight of modern trucks far exceed the weight of any sort of horse or oxen powered cart that would’ve been the truck of the times when these bridges were built. Those times seem to be something like 1840-1860. The one with the car on top (that’s me, several years back now) was built for exactly $100. So,it says in the published town history.
Let’s see now! 1850ish, $100, and it’s still usable; versus modern engineering….$million$, with a lifespan of 40-50 years.