Ask YC: Why aren't high-rises built by machines?

gravitycop · on Jan 31, 2009

Even if that meant having a very standardized building, it seems like it would be so cost efficient that the aesthetic compromise would be alright.

Skyscraper tend to be designed to be iconic, e.g. non-standardized. Building codes evolve, which also defeats standardized construction.

The new Freedom Tower (One of the World Trade Center replacements; a symbolic 1776 feet high), a hyper-iconic building, is lately estimated to cost around $1,000/sqft of floor area to construct. Simpler skyscrapers can cost as little as $200/sqft, so that's your competition. Your proposed venture needs to be able to 1) complete skyscraper projects at substantially less than $200/sqft, 2) meet building codes, and 3) convince authorities to grant construction permits for a radical construction technology.

Skyscraper construction, like house construction, is already automated to a great degree. Parts are mass produced in centralized factories, shipped to the construction sites, and put together like parts from a kit. Here is the brand new Trump Chicago being built with a helicopter delivering prefabricated parts: http://forum.skyscraperpage.com/showthread.php?s=000ea7e2e81...

astrodust · on Feb 1, 2009

I would suggest the major problem with constructing buildings like that automatically is that each floor has to be carefully prepared with reinforcing material long before the concrete is poured. I think for this reason alone you're going to find trouble.

While the arrangement of these rods is a fairly straightforward but tedious process for a human to do, it's particularly tricky for a machine to manage because of the highly variable nature of the structure.

If you had some kind of construction material that didn't require internal reinforcing, where it could be just applied as-is, then you would see a lot more automation.

As others have said, building codes and quality control would have to play a part here. A lot of automated manufacturing is subject to strict checks, but usually the resolution for a defect is to discard the part. In the case of a building, or even a part of it, that may not be so easily accomplished.

gravitycop · on Jan 31, 2009

why can't machines be built to automate much of the process [of erecting a high-rise]?

This might be a good place to look for answers: http://forum.skyscraperpage.com

The engineering section discusses construction technology.

oldgregg · on Jan 31, 2009

That's spot on, really interesting discussions.

likpok · on Jan 31, 2009

There have been a few recent developments (I remember hearing about a concrete 3D printer), but it seems that the technology just isn't there yet. The problem is that the robots need to be small (enough to be transportable and reusable), cheap (cheaper than construction workers) and mobile (small => you need many to slowly build up the building). Most robots don't have that level of sophistication yet. All the manufacturing robots are stationary and (relatively) large, and mobility is something of an unsolved problem.

This is not to say that it is impossible, just that I think there are significant engineering hurdles to robots building skyscrapers (maybe smaller houses first?).

pg · on Jan 31, 2009

It makes most sense to manufacture things when they're small, cheap, and made in large quantities. High-rises are at the other extreme.

russell · on Jan 31, 2009

I saw 0.01 version of one in San Mateo, CA about 20 years ago. The building was built from the top down. Each floor was built on the ground, cast concrete, I believe, and hoisted into place underneath the one on top. It probably didnt have any real advantages, because I havent seen it done again.

One would thing that simple, but well designed and constructed, housing would dominate, but it hasnt happened. Construction codes are one thing, but I think the real reason is that nothing can compete with fine contros and flexibility of humans when it comes to building large structures.

czcar · on Jan 31, 2009

There attempting to build something like this, http://www.engadget.com/2007/01/15/rival-robots-prepping-to-... . Personally I think its a horrible idea, I have a gross aversion to suburbia clones, let alone soviet style skyscrapers that all look the same. But I suppose it would be interesting. As gravitycop pointed out skyscrapers more often than not are ego plays so the more outlandish the better.

deepblue · on Jan 31, 2009

the machine does not have to be big... it can be a bunch of small spider like machines, or even more groups of machines: - material suppliers - welders - concrete ones (these can be essentially carrying tubes that are pump out concrete)

this might be the next step for building multilevel farms, for agriculture (building huge pyramids). I've seen mockups/studies done in Japan (I think) that talk about exactly this, spider like swarms of robots moving along rail like structures maintaining/buidling fractal like pyramid structures that are super-tall ;))

the only way to take agriculture/housing to the next level... have multi-level cities (and not what pseudo-multilevel that we have now)... - rail constructors (rails for welders/material suppliers to move along)

oldgregg · on Jan 31, 2009

Spiders are a fascinating if not slightly scary concept. I would if current construction methods would have to be simplified in order to reduce errors.

something · on Jan 31, 2009

maybe you are underestimating the extent to which this is already done? there are machines that eat steel and glass and produce windows and structural elements (wires, carpets, tiles, lightbulbs...)

the economies of scale come from not lugging these machines to every job site.

notaddicted · on Jan 31, 2009

I think that the cost of human labor is <10% of the cost of materials, so it would not make much of a difference.

I wish I could find some numbers for some recent projects, I haven't got anything to back this up.