As he neared the outskirts of the city the canyons of multi-storey buildings lined with coffee- and tea-houses gave way to the large squat shapes of factories, storage-halls and other industry. If it weren’t for the ramps leading below ground, or the occasional slid-apart roof of a shipyard revealing the envelope of an airship; one could easily overlook the sheer size of these buildings, sunken many levels into the ground.
NOTICE: I am looking for a solution within the confines given in the question. If your answer does not work without introducing anything to the world (e.g. super precise lenses, magical hotstones, etc.) please take the time to weigh up the pros & cons of whatever you introduce.
This question is set in my mind-bogglingly breathtaking conworld, where heavily armoured airships majestically float through the skies with help of a science-defying, yet well thought-through lighter-than-anything material1.
While you can make use of these facts & technologies in your answer. Making your answer work without them would make it much more useful for other people looking to solve the same or a similar issue
In order to achieve the desired aesthetic of having most of these buildings sunken into the ground, we'll have to excavate quite a lot of material.
E.g. for a building of 80x130m with 2 stories above and 3 stories below ground, we get a depth of about ~8m. That results in an excavated volume of 83'200 m3 - that is ~34 Olympic swimming pools1.
Now this leads to two problems in my understanding:
- Depending on the ground this means possible huge amounts of labour necessary for a comparatively little advantage over building all above-ground
- We have huge masses of dugout material of which we can directly use only comparatively small amount for building the above-ground walls and structures.
The crux is that rocky underground means we can quarry off quality building stone, but it's also more labour intensive to dig out. While softer underground means that we have an easier time digging, but we can't reuse much of the dugout for building...
1or 146'411'532 British Pints - thank you Windows Calculator
Area: The region I want to set these buildings & towns in is intended to be savanna-like to desert-like (take generously from Morocco and Namibia, sprinkle with Asia Minor, then roughly mix with a spatula).
Q: What conditions would allow for this way of building to be predominant in the described areas?
A good answer might choose to address one or multiple of the following topics:
- What kinds of ground/strata would benefit this way of building large structures, and why?
- What environmental conditions could benefit this way of building / maybe even necessitate it for large structures, and why?
- How could the dugout be used so that it is not purely a waste-material?
Technology: The world is set technologically somewhere between the industrial revolution and the invention of internal-combustion-engines. There's been heavy development and optimizations regarding steam-driven-engines as there is, at least in parts of the world, little to no oil available.
Electricity is something fairly new and so far doesn't go further than being used for creating light aboard airships and being used for telegraphy (little to no electric infrastructure).