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Comment by onetimeuse92304 | Hacker News Reader

I like to tell people that all engineering is about tradeoffs.

People who engineered bridges during Roman Empire had different tradeoffs to consider than people who were building bridges in 20th century.

Standing for a thousand years is rarely an ultimate goal when engineering a bridge although it is possible that Romans planned for longer timescales than us.

If we decided to build like Romans did, there would likely be very little infrastructure and many structures would simply be impossible to construct.

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"If we decided to build like Romans did, there would likely be very little infrastructure"

Why? The romans build lots of infrastructure. Roads, sewage, irrigation, .. and they used the materials and technics of their time.

Can't we really do better today, with all our advanced technology?

Or can't we, because everything has to be cheap, cheap, cheap?

I mean, the romans used slaves. That is cheap. But we have machines.

How much population did the Romans build for? How much weight were the Romans subjecting their structures to, and at what acceleration/deceleration?

Do you know the movements of the supply and demand curves of the materials required since Roman times?

These types of hypotheticals are a waste of time, and only serve to illustrate hubris, as if something as complicated as comparing Roman construction and resources to modern day construction and resources could be possible.

"as if something as complicated as comparing Roman construction and resources to modern day construction and resources could be possible."

Well, one can compare the results.

Personally I like things that are build solid and can last a 1000 years.

But I don't think I said the romans build better. They just had a different intention: long lasting.

> Can't we really do better today, with all our advanced technology?

You implied a whole host of things with this statement, and considering the topic of this thread, also ramming a Roman bridge with a fully loaded modern day cargo ship.

The point is there are so many moving parameters, it is nonsensical to take 1 result of 1 technique from 1 point of time and use that as a basis for what one can expect at other points in time.

Erm, that was just directed at this point, which I quoted:

"If we decided to build like Romans did, there would likely be very little infrastructure"

The bridge has lasted a thousand years because nobody is driving 18-wheelers over it. It has nothing to do with the intentions of the builder.

"It has nothing to do with the intentions of the builder"

Why not? They did not have the intention to make the bridge resistant to such heavy loads, as that was not a use case at that time.

They had the intention to make a bridge to last as long as possible for the traffic at their time. And they surely succeded with this.

Now whether they also could have made a bridge that resists 18 wheelers for 1000 years, well, I don't know.

This is survivorship bias in action. They intended to build a bridge. That is all we can infer from the fact that a bridge exists. That they used available materials and the bridge was not abused by subsequent usage outside its design spec is not proof of any specific intention on the part of the builder. That exists only in your head. It's like assuming dinosaurs died in specific spots with the intent that their bones petrify and fossilize. You're reading too much into not enough facts.

Maybe, but lots of roman buildings endured the time in much better shape, than many buildings that were build after them. Have you seen some of them in front of you? I have and I am impressed. (I am in italy right now to go look at some more).

Also we know a bit more about the romans than just their bridges.

You can't use Roman techniques to build a bridge over a river that's a couple of kilometers wide that can carry heavy trucks, unless you're thinking of building a dam.

It is the same type of person that says Romans were more ecological because we have cars and they had carriages drawn by hand or by horse.

Which is to say "let's just pretend that all of those pesky details do not exist".

This is an excellent point, the tradeoffs are specific to the time, place and needs of the builders

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