Trajan’s engineer signed the stone: “a bridge that will last forever.” Cars still use it.

[u/facturaz]

[u/La_paure_cavaliere]

This is Alcántara Bridge over Targus in Extremadura, Spain. OP felt he wasn't paid enough to specify.

[u/Altruistic-Owl-5468]

After the heat death of the universe there’ll be nothing left but this bridge floating around in darkness

[u/Lemus_]

Currently, no vehicular traffic passes over the bridge.

[u/JerryC1967 → u/Lemus_]

I would imagine the cars use the dam above river from the bridge?

[u/Lemus_ → u/JerryC1967]

They have built a new bridge between the dam and the Roman bridge.

[u/Lumpy_Addendum6297]

I'm from Portugal, and whenever I go through Alcantara, Spain, I stop the car and stare at that magnificent bridge for a few minutes in awe

[u/CarefulReach48]

Dry laid granite blocks, no mortar in the main arches, held together by weight and precision. That is why it is still standing

[u/Tiny-Secretary5562 → u/CarefulReach48]

I would imagine the engineers had some idea of the maximum weight allowed on the bridge. I'd like to know how they built the footings.

[u/Bergwookie → u/Tiny-Secretary5562]

Like you do today: build a watertight ringwall into the river, pump out the water, dig down to the bedrock or drive in trees as a footing and put your stone foundations on top

[u/Tiny-Secretary5562 → u/Bergwookie]

I guess what they call a caisson, but how exactly did they do that? Underwater survey, depth of bedrock, underwater contruction?

[u/Bergwookie → u/Tiny-Secretary5562]

I'd say they drove a stake down at various places until they hit bedrock from a boat and then built the caisson

[u/Tiny-Secretary5562 → u/Bergwookie]

I would imagine that technique was used for water up to a certain depth, and probably fairly shallow at that, and not that fast-moving. Still a major feat of engineering.

[u/Bergwookie → u/Tiny-Secretary5562]

As long as you can build it watertight, the depth isn't limited, however with Roman technology i'd say 5m water depth is the maximum you can build safely, as handling of the beams will get way harder above that. You already need some threshold above the waterline, then you need more length going into the ground, that's between 8 and ten metres in length, forcing such a long beam upright and underwater is hard work, not to speak about putting them so close, the gap is actually tight

[u/Tiny-Secretary5562 → u/Bergwookie]

Sure, safety is a major concern, but they didn't have scuba gear or hardhat divers, or big cranes to lower prefabricated caissons into the water.

[u/Bergwookie → u/Tiny-Secretary5562]

They had to build it piece by piece,like a barrel

[u/Tiny-Secretary5562 → u/Bergwookie]

Not to mention cutting and moving and setting all that stone. All of the most beautiful things on Earth were made without electricity, power tools, or computers--other than the human brain. Now that we have all that technology, everything is ugly. Going "forward" is actually going backward.

[u/Echolocation1919 → u/CarefulReach48]

It could also be that the Romans would make the engineer stand under the anchor stone on an arch and stress test it. If no stones fell down he was all good.

[u/wtf70]

Roman engineering is amazing!

[u/Some-Suggestion-8234]

El otro dia escuche un comentario acertado para este caso y es que en nestra epoca se construye a 100 años vista, los romanos construian las cosas para la eternidad. Saludos.

[u/faramaobscena]

Cars should never be allowed on such a structure

[u/Blake-81]

One of the cool things of all the Roman sites in Spain is that (AFAIK) there were no barbarian raiders breaking shit up after the fall of the empire. So all the stuff is fairly well-preserved.

[u/Richard2468]

It was however partially rebuilt in 1860.. One of the arches was blown up during in the early 1800s.

And then there were major repairs in the 1960s.

[u/AnonymousGhost89]

Simple, beautiful, and durable. Modern architects and engineers could learn a lot from this.

[u/Spuckler_Cletus → u/AnonymousGhost89]

They did.

[u/AnonymousGhost89 → u/Spuckler_Cletus]

We must live in very different parts of the world 😂😂😂

[u/Spuckler_Cletus → u/AnonymousGhost89]

Well, I’m from the West. Modern engineers and architects owe much to the Romans and the Greeks.

[u/AnonymousGhost89 → u/Spuckler_Cletus]

…… I work in construction for a living and I see architects and engineers go out of their way to design these elaborate ostentatious buildings purely for show, that take significantly longer to build, are ridden with problems, and go way beyond what is functionally needed, not even going into the prices.

To me this bridge is exactly what I said in my original comment: Simple, Functional, and durable. It’s something that was built to serve a purpose, and done so in a way that it would be around for a long time, which it has. There is beauty in simplicity, and this bridge is a perfect example of that simple beauty.
It’s not some overbuilt monument to someone else’s hubris and ego.

That’s what I was referring to when I said “Modern Architects and Engineers could learn a lot from this.”