How do ancient buildings survive hundreds of years of natural disasters e.g. earthquakes?


How do ancient buildings survive hundreds of years of natural disasters e.g. earthquakes?

In: 72

Mainly luck but also a bit of disregard for cost

The ones you see today are the ones that survived, you don’t see the 99.9% that didn’t make it

Old buildings were also built with poorly understood materials so they were over built. Any idiot can build a bridge that stays up, it takes an engineer to build a bridge that barely stays up on time and on budget. If you’ve got thousands of people and can just build your building out of huge stone blocks it’ll do pretty good because it’s dozens of times stronger than it needs to be and a hundred times more expensive

Keep in mind that the ancient buildings still around today are not an example of the average building of that time, they are just the ones build strong enough to be left.

This is a case of survivorship bias.

So the ancient buildings still standing today are the ones that were built the toughest back in the day.

Of course even the ones that are still standing aren’t just because they were built right, but because they were maintained and repaired well over the generations.

Building methods have changed. reinforced concrete allows you to build things that you could never build with just concrete or other more ‘primitive’ materials, but it simply won’t last that long.

Modern techniques are not always optimized for longevity or to withstand once in a century disasters but often simply for cost.

Building codes ensure that builders can’t skimp too much, but it still is a question of money when it comes to how much more than the absolute minimum they want to do.

As others have said, mostly luck and survivorship bias.

In particular, there are some ancient buildings that are made of particularly tough materials. That basically means rock.

Once you cut a rock into some shape it takes a long time for that shape to change from just natural erosion. Giant piles of rocks don’t tend to move around much either.

So the Pyramids at Giza, Stonehenge, the Great Wall, etc. have some pieces crack off and get a little weathered around the edges. All the structures made of things like wood, straw, skins, etc rotted away centuries ago.

Ideally they are located in a region with few earthquakes and/or have not been subjected to severe earthquakes during their lifespan.

Many ancient buildings did fail to earthquakes, just we mostly don’t see them because their remains were salvaged into new buildings.

There have also been modern day instances of major earthquakes hitting regions with ancient buildings in them for the first time since many of them were built. Many fail.

Of those that survive – these buildings often have a lot of redundancy in them due to the nature of construction techniques and materials when they were built. Eg lots of walls that are also fairly thick. This eats up usable space inside pretty fast but can give these structures a sporting chance of surviving earthquakes.

It’s not “the ancient buildings” it’s the ridiculously overpriced and overengineered ancient buildings. Regular buildings didn’t even survive the non-natural disaster level elements