I have worked in building maintenance and repair. One thing that is extremely hazardous to a concrete building is too much water. I have seen many concrete planters that crack and result in water leaks for lower levels. Standing water in concrete structures is a huge no no. I do not have a lot of experience in engineering on this matter, but whenever I see a solar punk sky scraper with vegetation on its exterior, I think “cool, but maintenance and inspection must be horrible! Repairs must cost a fortune when those roots and moisture degree the concrete.”
What engineering controls does one need to create a durable structure while exposed to constant moisture needed for vegetation, and the vegetation itself? I know there are green sky scrapers with gardens all over. What is the maintenance of those structures? Do they hold up\last as long as bare concrete structures?
We discussed it a bit recently here https://slrpnk.net/post/1783839
I think many of the projects we see actually done (and which inspire artworks) are vanity projects that are not very practical or cost effective (like full grown trees on roof-tops).
But there are many ways to green roof-spaces that do not require standing water or all that much maintenance.
Very much agreed with the others, unfortunately it’s mostly inspired by city or corporate vanity projects. I’m sure it can be done, if planned from the start with proper reinforcement, drainage, and mitigations for roots, but the cityscapes with trees stuck haphazardly to buildings we often see in art would probably be more hazard than ecological improvement. I recently started working on some scenes of (hopefully!) more realistic solarpunk locations, and I’d love to do some pictures of cityscapes that are genuinely solarpunk next. (Fewer skyscrapers, fewer roads, more focus on pedestrian accessibility and public transit, perhaps some greenways to allow for safe animal movements, etc).
I’ve noticed that for a bunch of folks, solarpunk is the aesthetic or at least it’s defined by the visual art, so I think the kind of utopian star trek skyscrapers and the tree-covered roofs are kind of distracting from the more solutions-oriented stuff.
- @MxRemy mentions self-healing concrete
- there’s also fungal concrete
- looking back through time, Roman concrete was also self-healing (as well as being longer lasting and cheaper to manufacture (as well as using slightly less energy))
- as a personal opinion, skyscrapers really don’t have any place in a solarpunk future
- following along the lines of Christopher Alexander’s “21. Four-Story Limit” from A Pattern Language
- “There is abundant evidence to show that high buildings make people crazy.”
- “In any urban area, no matter how dense, keep the majority of buildings four stories high or less. It is possible that certain buildings should exceed this limit, but they should never be buildings for human habitation.”
- we already have plenty of land space – if we re-cluster our suburbs into medium density, we can easily absorb the excess from de-clustering large cities
- following along the lines of Christopher Alexander’s “21. Four-Story Limit” from A Pattern Language
I like neighborhoods and cities with mid or low rise housing. I spent a lot of time in Turin, Italy (I’m American) and most that city (and other European cities) have mid rise apartments. They’re in the 6 to 8 story range a lot of times, but still no high rises. It makes for a great walkable city. The street I lived on in Turin was this huge wide boulevard that probably could have accommodated six to eight lanes of traffic with a turn lane in the middle. Instead there was a two-lane road in the middle with turn lanes, followed by streetcar rails further out, then a line of gorgeous trees, then parking for local businesses, then a side street to access the local parking and finally a nice wide sidewalk in front of the shops and apartments.
It’s a great looking city for anyone who happens to be in Northwest Italy!
Christopher Alexander picked the Four Story Limit for aesthetic and mental reasons – but historically, older buildings were generally limited to four stories because of climbing too many stairs – the six to eight story limit of most European city cores comes from the introduction of the first elevators that couldn’t really handle more than six stories
- @MxRemy mentions self-healing concrete
Isn’t the Hoover dam concrete‽
Standing water in concrete structures is a huge no no.
Isn’t this one of the big reasons why the Florida apartment complex collapsed?
What engineering controls does one need to create a durable structure while exposed to constant moisture needed for vegetation, and the vegetation itself?
I started thinking about this yesterday too, after watching the Ask This Old House guys remove moss from a roof, explaining that it will retain water and shorten the life of the shingles. As some houses are prone to moss, you’d think we’d just figure out how to make a bio-roof. That seems like your step one to a veg-roof.
I don’t know anything about this stuff like AT ALL, but what about something like self-healing concrete? Maybe the Arcology field has already been working on this stuff, if they have I’d love to read about it.
Water is actually good for concrete. Well… more like it doesn’t care. https://www.youtube.com/watch?v=b43Iz2OoUNk
Problem is that iron rebar in the concrete rusts and expands cracking the concrete. https://www.youtube.com/watch?v=PLF18H9JGHs
PS Sir Martyn Poliakoff, the professor in the first video, studies “green chemistry”. He’s a great man.
Thanks for the vids. I’m not sure “water is good for concrete, or doesn’t care” is accurate. In a controlled environment that may be true, however with corrosion from polluted rain (the lime in concrete is dissolved with acid rain), expansion and contraction (especially with freeze thaw cycles), and biological processes that may be encouraged to grow in damp conditions, water is pretty bad for concrete; these are examples of what I’ve encountered that caused degrading concrete structures.
That said, I was thinking about it more and things like dams and drilled t shaft concrete piles are obviously exposed to constant water. I’m wondering if what I experienced has to do more with exposure to aerobic and temperature fluctuating environments as opposed to drilled shafts and dams which would be more isolated from those conditions I described above.
Even if water itself isn’t the primary mode of failure, I guess my point still remains regarding the vegetation of "green"buildings; roots and what not definitely will start to degrade concrete.
Thanks for the comment, it gave me some points to think about.
