[HN Gopher] What are those grids of glass in the sidewalk and wh...
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What are those grids of glass in the sidewalk and why are they
purple?
Author : vo2maxer
Score : 210 points
Date : 2020-01-03 20:30 UTC (2 hours ago)
(HTM) web link (www.kqed.org)
(TXT) w3m dump (www.kqed.org)
| [deleted]
| RangerScience wrote:
| Oh neat! I didn't know that Sacremento has this kind of
| underground.
|
| Also, anyone else having flashbacks to Dinotopia sunstones?
| SubiculumCode wrote:
| Indeed. I've been living in the area for some time now and had
| no idea. I wonder if there is some area that can be explored?
| daxorid wrote:
| This is interesting, but raises a question. The article mentions:
|
| _In San Francisco, vault lights are mostly used to illuminate
| sub-sidewalk basements -- ie. basements that extend under the
| sidewalk._
|
| How does this work, legally? Where I live, sidewalks are property
| of the city (or the HOA, in some cases), and I'd presume the same
| in SF. Does the title of the sidewalk-adjacent property allow you
| to excavate N feet beyond the property line? Or is the sidewalk
| instead a publicly-managed easement on your own property? Who
| pays for installation and maintenance of the vault lights? How
| does coordination of engineering/construction of the sidewalk-
| basement boundary work?
| yardie wrote:
| That must be a western concept. On the east coast it's common
| for sidewalks to be owned by the landowner yet have to remain
| unencumbered for the public right of way. Some owners find out
| the hard way that they are also responsible for maintaining the
| sidewalk when the city hits them with a notice.
| vidanay wrote:
| I would guess these situations pre-date any of the current
| zoning laws.
| dualboot wrote:
| This is correct.
| Digory wrote:
| It depends on how the lines are drawn. If you want to plow a
| road through existing houses today, it gets condemned -- taken
| by the government, lock, stock and barrel. In a new
| subdivision, they'll often deed the streets over to the city.
|
| But sometimes, especially in the old days, the city just got a
| "right of way," not title to the land. And in that case, the
| owner could do anything it wanted, so long as it preserves the
| right of way. So if the city had a right of way to a sidewalk,
| it doesn't matter what you do under the sidewalk. Here's an
| interesting discussion about right of way edges that appears to
| use Washington (State) law.[0]
|
| [0] http://mrsc.org/Home/Stay-Informed/MRSC-
| Insight/November-201...
| glangdale wrote:
| Thaddeus Hyatt, the inventor of those grids, has a fascinating
| history, including backing militant abolitionists (I think it's
| unknown whether he bankrolled John Brown) and being jailed by the
| Senate (?) for refusing to testify.
| brlewis wrote:
| Wikipedia states his financial support of John Brown as fact:
| https://en.wikipedia.org/wiki/Thaddeus_Hyatt
| StClaire wrote:
| Denver has these, you can see them on Larimer and Market street
| in LoDo. Around the 1890s, the locals dug out a series of tunnels
| through the city. The snows would come in and people would just
| go underground for a few days for business. There was a bar that
| closed about a year ago called the Blake Street Vault--it used to
| be a bank--and if you asked they would take you into the basement
| to see the vault and the dumbwaiter. You can see down where they
| plastered over some of the wall, it used to have a teller window
| right there open to the tunnels for customers.
|
| Supposedly, you could go from Union Station all the way to the
| capital building underground (but I doubt that).
|
| I'm sure most of the tunnels aren't passable, possibly collapsed,
| filled in, or flooded. But I seriously want to go down and try to
| map out some of them to be restored like they did in Seattle.
| rconti wrote:
| Stupid question: Wouldn't the snow cover the vault lights? (I
| know, they could clear them by clearing the sidewalks...)
| taeric wrote:
| I thought this was going to be in Seattle. :) It is neat to
| notice these all over the place.
|
| The underground tour is more than a little crazy to see just how
| built up the city literally is. My favorite related topic were
| the spite mounds.
| hinkley wrote:
| I think the Seattle Tour has a bunch of factoids of which each
| guide chooses their own subset. First time I took the tour,
| they mentioned that a bunch of the material for raising the
| streets came from San Franscisco, which had quite a thirst of
| lumber (and would occasionally catch fire and burn down,
| boosting that demand).
|
| Flat bottom boats hold a lot of bulky cargo, but they're a
| nightmare when empty. So on the return trips they ballasted
| them... with fill dirt.
| vineyardmike wrote:
| That tour is great! I take everyone who visits seattle to it.
| I've had the same tour guide, and each time was different as
| well.
| pkamb wrote:
| The new Seattle waterfront sidewalks have a similar inlayed
| motif of large purple glass tiles. Was cool to notice the
| design inspiration.
|
| https://www.washington.edu/news/2017/05/18/seattle-seawalls-...
|
| https://www.kuow.org/stories/seattle-s-new-seawall-was-built...
| rconti wrote:
| I grew up in Seattle. I still need to do the tour some day when
| I visit. So many cities have underground tours and I've heard
| great things about them.
| ilammy wrote:
| Modern people accustomed to ubiquitous electrical lighting would
| probably think of 19th century and beyond as quite dark.
| AstroJetson wrote:
| I had a sail boat where the prior owner had installed 4 of these
| in the cabin roof. They were little domes and did a good job of
| lighting the cabin in the day, and marking a path at night.
| hinkley wrote:
| I learned about these many years ago, but the whole "you can
| see a fire in the hold" angle never occurred to me. Accurate,
| useful, and macabre.
| odonnellryan wrote:
| Yes had one in my old boat. Nice, but not so nice where I'd
| install them on my current sailboat.
| dcminter wrote:
| Perhaps the inspiration behind this?
| https://www.bbc.com/news/magazine-23536914
| bynkman wrote:
| I know of a few places in Kansas City that have under sidewalk
| vaults. In some of those places they have warning signs about not
| parking. Here's one. https://bit.ly/36qPLvy
| im3w1l wrote:
| One thing I would have liked the article to explain is when this
| is preferable over solid glass.
| WorldMaker wrote:
| Safety/stability, presumably, given that people might stand on
| top of them (many of the examples here are embedded in
| sidewalks) and they'd need to be weight bearing. Safety glass
| is a relatively more recent invention than some of the examples
| (at least one example in the article dates back to the mid 19th
| century), and a very recent invention if specifically
| restricting to the types of plastic-based laminated glass
| trusted in things like modern car windshields and observation
| floors today.
| WorldMaker wrote:
| Also, the article points out that many of them had
| interesting prismatic shapes to bounce light around in
| interesting directions, and making those prisms would be
| easier as smaller individual components rather than one large
| piece of glassblowing, even if they had the technology to
| make it safe enough at that size.
| DanBC wrote:
| The earliest patent of deck lights, which predate vault lights
| or sidewalk prisms, is from 1684.
|
| This site includes some images and patents
| https://glassian.org/Prism/index.html
|
| There's a patent for sidewalk prisms from 1834.
|
| As other people have said, the glass broke.
|
| > In 1834, Edward Rockwell patented a round iron plate with a
| single large lens, but Hyatt later complained in his own patent
| application, "These glasses are extremely liable to fracture,
| and when broken leave large and dangerous openings within their
| rims...". Rockwell's plates are rare today; I know of only
| three examples of the iron covers and none of the lenses
| vineyardmike wrote:
| Presumable cost or manufacturability? Big sheets of glass were
| not feesible in the 1800s
| myself248 wrote:
| Tempered glass is relatively modern. They didn't have strong
| solid single panes of glass back then; the concrete with glass
| inlays was the best way to make it stand up to traffic above.
| ipqk wrote:
| Avoid peeping toms.
| aclatuts wrote:
| I always thought it would be interesting to build vertical
| greenhouses with something like this, in the floors or walls,
| siphoning natural light between the floors
| altgeek wrote:
| In downtown NYC, there still are areas of sidewalk with these.
| abuckenheimer wrote:
| Just remembered the puck building[1] has these on the sidewalks
| surrounding the Houston street side, if you go into the Eastern
| Mountain Sports store and down the stairs you can see them from
| below.
|
| [1] https://en.wikipedia.org/wiki/Puck_Building
| robk wrote:
| These are ubiquitous in London
| iDemonix wrote:
| And many other parts of the UK. I've seen a fair amount in both
| Oxford and Nottingham.
| NeedMoreTea wrote:
| Plenty up north too. Don't ever remember seeing a purple one
| though, pretty much always the green of very thick glass.
| huangc10 wrote:
| I walk past these all the time thinking they're just interesting
| design patterns on the floor...how dumb of me. Insightful article
| and fun read.
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(page generated 2020-01-03 23:00 UTC)