The stone arch bridges of the 1800s

[geoff59]

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. 

[HankRocks]

It is a beautiful bridge. Sure hope the "taking it apart to study it" does not backfire!! That would be a real loss. Best laid plans.....

[mohs]

integrity is what I think
when I think stone arches
and keystones

and the photography is excellent too!

[liveoak]

Cool bridges & cool photos geoff59.

I know when we lived in NY State there were plenty of stone walls,

AND mason's that knew how to build these kind of things.

Those arched bridges are a very ancient design, built on the "Roman Arch" principal.

"The arch is a simple way of spanning a wide area with smaller stones.

Wedge-shaped stones fill the space in between two outer columns or abutments.

In the construction, a temporary wooden arch is used to hold the stones in place;

once the central keystone is in position, the timber support can be removed.

The weight of the stones themselves keep the integrity of the arch in tact."

Read all about it here :

christopherpjones.medium.com/architectural-basics-the-roman-arch-cd6242dd6e39

Patty

[rockjunquie]

There's a cobblestone bridge at the island where my mom and her's grew up. It is (or was) the only one like it in the world after the one in France was bombed during WWII (it may have been WWI). Anyway, it was finished in 1928. It consists of locally quarried blocks of granite simply topped on top of each other to allow a lattice for the tides to flow.

It is still used today and I can tell you the traffic over it gets really hairy. Bailey Island was a sleepy fishing town until it was "discovered", now it is like a mini Martha's Vineyard. Sad, really. A way of life has disappeared.

en.wikipedia.org/wiki/Bailey_Island_Bridge

I took this a few years ago.

[rockjunquie]

Dec 27, 2022 14:56:31 GMT -5 Bravura Cabochon Designs said:

Dec 27, 2022 13:26:17 GMT -5 rockjunquie said:

There's a cobblestone bridge at the island where my mom and her's grew up. It is (or was) the only one like it in the world after the one in France was bombed during WWII (it may have been WWI). Anyway, it was finished in 1928. It consists of locally quarried blocks of granite simply topped on top of each other to allow a lattice for the tides to flow.

It is still used today and I can tell you the traffic over it gets really hairy. Bailey Island was a sleepy fishing town until it was "discovered", now it is like a mini Martha's Vineyard. Sad, really. A way of life has disappeared.

en.wikipedia.org/wiki/Bailey_Island_Bridge

I took this a few years ago.

I’ve been over that bridge a few times, the giant stairs are right around there if I remember right.

Yup, you got it. Beautiful place. I've spent a lot of time there.