How can I make the supporting pillars of an underground city less obstructive?

Question

Node is the last active city of the lizard people. Node was built to be a self-sufficient city and a nexus of an interconnected bunker system. It was a vanity project from the peak of the lizard empire, so they designed Node to be as spacious as possible.

The problem is with the pesky supporting pillars, necessitated by the ~500 m ceiling-floor distance and the fact that the city being bombarded was a possibility. They're obstructive and break the illusion. Since the designers positively and absolutely didn't want their magnum opus to look like something out of Girl's Last Tour, they had to find a solution.

The question is then, just how could they create the illusion of a large, open-space without compromising the pillars' function? I'd normally try to find a solution by creating models in Minecraft, but I deemed that to be too time-consuming.

They have access to any scientifically possible technology (so CNTs, robots, etc..).

However, you can't wrap metamaterial around the pillars to make them invisible, you can't make the pillars invisible, you can't drug/mind-control/indoctrinate the populace into thinking there are no pillars, and neither can you redefine what a pillar is. I won't allow you to do any of these.

Also, lizard people have very similar personalities to humans, meaning that if humans on average find something soul-destroying (mass-produced apartments and concrete), then so do lizard people. Simply put, you can apply "space-saving" tricks here from IRL.

Answer 1

Mirrors, greenery, sculpture and waterfalls.

You can’t hide these things. The best you can do is make them more easily ignored or more pleasant to look at.

Mirrors provide the illusion of space and openness in architecture. Fully mirrored surfaces can seem to ‘disappear’ on suitable days, and even if they don’t trick your eye into thinking they’re not there they will trick the eye into thinking there’s more space between the pillars than there is.

Greenery makes humans feel happier, and so I assume it will make your lizards feel happier. Deck out the bases and capitals of the pillars with hanging gardens. You may need artificial lighting.This won’t hide them, but it will make people see them as enhancements rather than obstructions. Plus points if they’re public parks. Everyone loves a nice park.

Waterfalls from high above provide cooling effects and also obscure the pillars (while looking pretty). If your lizard men are cold blooded but also work in warm places they might be glad to have some cooler areas to retreat to at the end of a working day. Use with caution: drainage may be an issue.

Finally you could sculpt on or around the pillars. “You say this is an obstruction? Nay! This is a symbol of the might of the lizard empire, behemoths of stone and glass holding aloft the very sky itself!!” - of course, this very much depends on the aesthetic tastes of the imperial lizard folk, so might not be good long-term. “Jormungandr striking a pose” might not translate well from classical to modern tastes!

Answer 2

Build skyscrapers around them

If you can't hide, camouflage. Turn the pillars into the city's skyline by building a unique looking skyscraper around each pillar.

Answer 3

Catenary arches

https://i.pinimg.com/originals/1c/82/bd/1c82bdf9a6060f96566a9c00c2349ddf.jpg

The catenary arch is the strongest arch. It has been used to hold up ceilings for centuries. Substitute arches for pillars. This opens up the space between and the space under the curve looks more open.

Answer 4

Your pillars should already be invisible already.

How are they able to see the pillars in the first place? Your under-city should be pitch black. Just don't put lights on the pillars.

If there is enough artificial lights under your city your people can see the pillars, all you need to do is mount low power lights on the pillars so they blend in with the background lights.

Keep in mind you will have some truly massive power needs to actually light your under-city enough to even see the pillars in the first place.

Answer 5

Place them off-grid

Placing the pillars more organically and not in a grid, covering them with greenery as per other answers, and camouflaging them among trees (nurtured by artificial sunlight) would give the illusion of being in a dense forest rather than underground.

Answer 6

Your biggest problem is that

Smaller pillars will collapse under their own weight

Assume your pillars are made from the surrounding rock, and that for reasons of practicality that rock is sandstone. (Strong in compression, relatively easy to quarry.) In the real world, we have sandstone pillars such as the Old Man of Hoy. That's only 137m, but it's about 10-15m wide. It is one of the largest free-standing pillars in the world, and probably the largest with near-vertical sides. Interestingly, that gives it similar dimensions to the tower of Ulm Minster. Both of these only need to support their own weight, not the weight of any ceiling above them, so any supporting pillar made of stone would necessarily be larger than this. And both these are still only a third as high as your target. Width tends to increase by the square of height, so you could reckon on your pillars being 9 times wider. And they still can't take any extra load yet.

Based on this, we simply can't escape having enormous pillars if we're leaving them in place from the quarried rock. Even reinforced concrete won't give us substantially different performance to solid stone.

The only answer then is

Make the pillars out of something other than rock

Skyscrapers such as the Burj Khalifa certainly exceed this height, and the actual top floor of the Burj Khalifa is about the height of your ceiling. (The rest is just a spire.) Skyscrapers use a steel framework, so your roof pillars could certainly use a similar principle. You could even construct them as skyscrapers, making the pillars somewhat wider but using them as residential/office space to increase the living space available. This would be a logical use of the volume of the cavern, instead of building structures from the cavern floor. Alternatively the pillars could be made smaller than a skyscraper width if all you wanted them for was structural strength.

Conceptually, the volume of the pillars could be reduced further by using more exotic construction materials such as Kevlar or carbon nanotubes. (Maybe the Lizard Empire have technology which we don't have yet.)

As an aside, I find the idea that the population would just live on the cavern floor is boring, unimaginative and frankly also naive and unrealistic. I wouldn't buy into that as a worldbuilding concept, unless we assume a "City of Ember" scenario where the whole place has reverted to semi-barbarism. Living space is about surface area, and there's a lot of surface area up those pillars and inside the pillars. Also up the cavern walls (like humans, lizards will not respond well to fully-enclosed apartments, but apartments looking out over the cavern would be cool and even desirable), and even in the cavern roof. And with three-dimensional living spaces and more advanced technology, we could also assume three-dimensional transport systems, with high-speed cable-cars running between pillars at different heights along a web of transit cables. Build a world which fits the technology and space. Show us something new. Don't just give us yet another copy of 1930s Manhattan underground.

Answer 7

Option 1: super-large tensile support structures

It may be possible to distribute tension through specially designed structures. If the dome is high enough then the ceiling's weight may be offloaded to side columns.

^{https://www.hisour.com/history-of-modern-period-domes-32124/}

But this solution doesn't properly communicate the sheer awesomeness of the Lizard people. Therefore...

Option 2: Put the pillars outside. Inverted. And falling towards the sky.

The Lizard scientists are really, really crafty. They anchored what would eventually be the roof of Node to extremely resilient tethers, and tied these to a captured asteroid placed in orbit - now a ballast to an inverted support system.

As a bonus, they gained a space elevator. Cheap space exploration, anyone?

Answer 8

The pillars have the same electroluminescent coating as the ceiling.

With ordinary paint, the colours would match but the pillars and the generally artificial shape of the sky would be made obvious by the different amounts of light hitting different parts of the pillar/ceiling structure.

But if the paint itself glows evenly all over, then the whole thing looks more like a sky (albeit maybe a cloudless, sunless weird alien twilight sky, probably not the exact colour of a real sky) and the pillars and the shape of the roof are much less obvious.

Answer 9

Physical Pillar-Replacement Systems:

Dome: A massive arched dome can be constructed in such a way that forces press against each unit of the dome all the way to the ground. Check out Geodesic Domes.

Laser Suspension: If the lizard people have an abundance of energy, they can suspend the dome through laser light.

Magnetic Suspension: Magnets can also be used to exert a force. This will, of course, have significant consequences on electronics and magnetic applications. But it is possible.

Biological Systems (my favorite): You're working with lizard people. So do some homework on lizards and learn all about them. Lizards don't see or think like humans. Lizards are highly visual communicators and can often see in the UV spectrum. (see article here)

Thermal Cloaking If the lizard people are much like snakes and not lizards, the pillars could emit low levels of infrared and mask their appearance.

Pillars as Lizard Communication Devices Lizards are far more visual than auditory/olfactory (like humans). They would likely have large, tall, visible communication methods. The lizards in my backyard get on top of my fence or even roof and fan their colorful dewlaps to threaten males, attract the ladies, and defense.

It seems reasonable that the lizards would use these tall places to communicate.

Moreover, if the lizards have any visitors, they may make their pillars (or perhaps only certain pillars) communicate in the UV spectrum to allow private or lizard-people-only communication. Humans may even bring translator devices to see these messages.

Build Vertically: Lizards in real-life use three dimensions to get around. They aren't afraid to get high up or low down. You may want to build your city up so, even in an hierarchical way.

Camouflaging Systems: As mentioned in other answers, mirrors, greenery, carvings, and other artwork can work. We use look-alike trees to mask cell towers. A similar system could be used, but mimicking other natural sights (giant stalactites, for instance).

Environmental Means: The roof of the cave could be obscured through heavy steam or smoke. The obfuscating gas could be natural or artificial. The pillars could be camouflaged or utilized as previously mentioned, but their tops could be obscured.

Answer 10

Since it's an artificial environment anyway, scrap the open-sky motif. Make the ceiling of your warren resemble the canopy of a forest, with the pillars positioned and designed as the trunks of great trees. You could even expand your city that way by giving the pillars 'branches' that provide a multi-level cityscape.

Answer 11

If it's possible (and I assume it might be, considering the Lizards are able to make such grand feats of engineering), I would suggest quantum levitation with superconductors. I'm no scientist, but the basic gist of it is that if you super-cool superconductors and put them over magnets, they can be suspended in the air. This way, you would be able to substitute pillars with gigantic magnets holding up the ceiling. You'd have to clear the area the magnets are placed for safety reasons, but other than that, you have a very open space, and no pillars! Here's a video of quantum levitation in action:https://www.youtube.com/watch?v=Ws6AAhTw7RA Just scale this up a million times, and there you have it!

Answer 12

Use a single, giant pillar in the middle of the city

Something vaguely similar to Midgar from Final Fantasy VII. Remove the grid-placed individual pillars. The single pillar could then be crafted into an appealing shape (arched at the top and bottom), and could be made into a tower block to house Node city hall and high end apartments for the rich lizards. The exterior could be covered with foliage (grow lights would be needed for living plants), faux green grass/ plants (no need for water or lighting), or textured brown cladding to make it look like a tree trunk. It would need to have a large diameter, which in this case is a good thing.

This would depend on how big the "roof" is, of course. If it's more of an oblong shaped canopy, you might need two large central supporting trunk/ tower blocks.

What are the pillars supporting? If it's an above-ground city or something with considerable weight, there may be a need for pillars along the edges as extra support, which could also be crafted into tower blocks. These could then be crafted in the same way as the central pillar (albeit on a smaller scale); arched shape, nature-themed exterior foliage or faux trunk cladding. They could also contain smaller suburban apartments. Steel support beams could then run from the main trunk to the smaller trunks around the edges.

This would then give the aesthetics of natural-looking structures, the usefulness of residentail and office space, and would leave large open spaces. It would also be less susceptible to bombardment than the original design as there would be fewer supporting targets to hit.

Answer 13

Lattice structures

The only reason columns need to be thick is to avoid buckling. Many small struts keep each other from buckling while letting light through. This helps them blend into the background, especially at a distance. https://commons.m.wikimedia.org/wiki/File:Astoria-Megler-Bridge.jpg

Lattice structures declined in popularity during the 20th century, because increasingly large industrial equipment made monolithic structures more economical.

Guy wires

Only one vertical member of a lattice structure absolutely needs to be in compression. The rest could be replaced by wires anchored to the ground (or ceiling). https://commons.m.wikimedia.org/wiki/File:Guyed_Delta_Transmission_Tower.jpg

Tensegrity structure

If guy wires to the ground and ceiling are unacceptable, then a pattern of wires and compression members can form a column. It’s easier to show than explain: https://commons.m.wikimedia.org/wiki/File:KrollerMuller_ParkSculpture4.jpg

Answer 14

Build them into the landscape.
Even lizards can appreciate beauty.

Pillars? What Pillars?

Gardens by the bay, Singapore:

Obfuscation with mirrors need not just be to mask vertical lines

Also Singapore Gardens by the bay

Add walkways, roadways, cycle ways, residences, facilities, gardens.

Guess where

Architectural features

Mosque, Brunei

Answer 15

Make them invisible

Just make the pillars invisible. It's possible in reality, so your civilization should be able too.

https://futurism.com/the-byte/watch-invisibility-cloak-military-use

Answer 16

Maybe make a domed city, with the dome being carved out of solid rock instead of built up out of smaller pieces.

A vast domed space could be cared out of solid rock under a mountain and possibly a very strong geodesic dome might be built under it to catch any falling rocks and to make the false sky look hemispherical instead of the probably taller parabolic shape of the outer dome.

I don't know how large the city is intended to be. If the buildings in it are multi storied then it can have larger population in a smaller area than an ancient or medieval city could.

My answer here: How can I prevent the invention of skyscrapers?1

Involves entire neighborhoods in buildings thousands of meters wide but less than 100 meters or 328 feet tall. Without that height limit requirement from that question those buildings could be built several times taller and thus could contain larger populations.

Of course with such buildings the occupants would not see the fake sky except when they went onto the roofs of the mega buildings. But using such mega buildings the city could be much narrower than a single story city with the same population. And of course the city could contain many domes hollowed out of the mountains and connected by tunnels.

Answer 17

Don't!

The mistake here is thinking that an underground city will look like a city. It will probably have several types of areas.

In the living/working/shopping areas, what you actually want to do is have buildings the size of skyscrapers, but horizontally. In these, you probably want to follow the mall layout: no large unobstructed views at all. In this case, structural supports are wherever and whatever they need to be, and nobody even realizes they are there. Tramways and elevators deal with moving longer distances.

The recreation areas... These are domes, sculpted to look natural. Here, you want to hide supports, or make the dome small enough that it has no interior supports. Different domes may specialize: a forest, a meadow, a set of soccer fields, a playground, etc.

The food growth areas... Probably resemble large greenhouses, using artificial lighting and maybe some hydroponics. They need to be designed to get harvesting equipment in and out. You harvest every single day, somewhere in the complex. They are probably located in the outskirts, or spotted through the complex.

Manufacturing areas... would probably be either a large chamber or a series of smaller chambers, with good connections to the transportation system.

Resource management areas (water storage, waste reprocessing, mining, etc...)... Except for the reservoirs, these would probably be larger areas with lots of supports, and lots of activity sorting, composting, or whatever. The water reservoirs would be large dark tanks, being carefully monitored to ensure nothing goes wrong.

I'm sure I've forgotten a few areas...

This type of design also means that a catastrophic failure only takes out a small part of your city.

Answer 18

What pillars? Those are sacred giant redwood trees. Hey! Stop trying to count the rings. Didn’t I tell you they’re sacred? No you can’t climb them either. Do I need to report you?

Answer 19

How about the beauty of natural underground caverns?

Answer 20

Turn them into an architectural feature, a point of attraction. They might be all the same, or each one might be unique, or they might be different types.

Some might contain level upon level of balconies or viewing platforms.

Some might be indoor waterfalls, fish or other fauna optional.

Some might be vertical gardens covered in lush vegetation of different types.

Some might be giant galleries for lizardfolk artworks

Some might be religious, with giant sculptures of deities or other suitable beings.

Some might be memorials, catacombed with thousands fo resting places for revered lizardpeople

...basically, each one can be a different type of tourist attraction. The rest of it is just the dully boring space between the interesting pillars.

Answer 21

Big natural stone pillars in an open space holding up a massive ceiling are beautiful in their own right:

https://www.bonneterremine.com/gallery

Answer 22

I would suspect any pillars of an underground city would be used as building space.

That way, rather than being in the way, they are put to good use.

In order to do this, the structural design of the pillars needs to be made to be hollowed out into a complex of many pillars and struts (i.e. a trellis structure) and have additional structural support for building inside and outside of them.

Thinking as the engineer to build such a structure I would build their core from the stone the city is carved from, and reinforce it with a variety of materials including concrete plaster, metal, fiber-based materials.

The aesthetics architect in may says that these should look like skyscrapers that go all the way to the top with arches branching out at the top like a forest canopy to widen their support on the roof. They would be covered with lights every so many floors of the floors with markets, shops and offices that never close due to no fixed day/night cycle and people rotating their sleep schedule for maximum efficiency. This would create brilliant lighted trunks all through the sky that are an addition not a detraction like the pillars of a cathedral.