Quad-copter video of Napa CA EQ damage - very cool

[JAE]

I posted this in the structural forum but I thought I'd put it here too.
Very cool video by a quad-copter flying over Napa, California after the earthquake - filming damage from beside and above the buildings.

https://www.youtube.com/watch?v=LQhYbfIz0n4

Wondering what they cost and whether a typical engineering firm could afford these and make use of them for investigations, etc. in hard-to reach places.



Check out Eng-Tips Forum's Policies here:
faq731-376

 

[RossABQ]

I am not familiar with the details of the seismic codes in CA, so the striking thing to me was the intact red tile roofs. Even on pretty severely damaged buildings, not a single tile lost? I can imagine that tiles shucking off onto pedestrians would be a major risk. Are the tiles required to be lightweight fiberglass? How are they fastened that they can survive a shake like this? My house has 30-yr-old tile in one section, that appear to be held on with two nails per tile.

 

[IRstuff]

The nails are enough. Pulling out a nail requires some amount of brute strength, and the shear strength of typical roofing nails is also pretty good. I think that for most earthquakes, the tiles will crack before the nails get pulled out.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

 

[JohnRBaker]

We have an old fashion terra cotta clay tile roof on our house in SoCal. The tiles are heavy and considered permanent in that they never wear out and only need to be replaced when cracked or broken. They are so heavy in fact that the ceiling joists in our house are on closer centers than they would have been if we'd had a woooden shake roof or traditional shingles. Also, terra cotta tile roofs are considered fully fireproof which helps with out homeowner's insurance.

Our house was built in 1979 and we've lived here since 1987 and during that time, we've had the roof worked on only once about 8 or 9 years ago when we had some dry-rot in the underlying plywood sheeting and they had to lift all of the tiles off the roof to replace the 10 or 12 sheets of plywood that were affected. They then relaid the original tiles having to replace maybe 50 or 60 broken and cracked ones. Over the years I suspect that more tiles have been cracked/broken due to high winds than earthquakes. When there's an 80 mph Santa Ana blowing it's amazing to watch it lift even those heavy clay tiles.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[IRstuff]

BTW, most lightweight fiberglass "shakes" are AWFUL. They leach and discolor. Ex-neighbor used something like CalShake, and within a year, one, and only one, pallet discolored; I'm saying only one, since it was about 3 lines of tiles that changed, while all the others simply faded over time. Another used a different product, but was fortunate in that he got the variegated colors and positions, and when certain tiles changed color, it was not detectable unless you had seen the original colors.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

 

[racookpe1978]

Sobering to note that almost every one of the damaged buildings was government-owned, government-used, or government-maintained..... The old churches were the exception - and they require "historic" protocols.

 

[JohnRBaker]

I'm not sure that that's an accurate statement.

At least from what I've read and heard, and know from personal experience (our #2 son lived in Napa for several years and we had visited the town on numerous occasions), the two buildings which seem to have sustained the most damage were one that was used for commercial and professional offices (that view of the top floor where it looked like a corner of the building completely collapsed onto the street) had recently been vacated by a private attorney, and the other building (on a corner with all the windows broken and most of the facade missing) was a sort of wine seller's co-op which allowed smaller wineries, that didn't have retail operations of their own, to sell their wines directly to the public.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[JohnRBaker]

Along the lines of using these sorts of 'drones' for scientific and engineering tasks, here a brief item from my alma mater on the subject:

http://www.mtu.edu/news/stories/201...-unmanned-aerial-vehicles-transportation.html

And here's the link to the video mentioned in the article:

https://www.youtube.com/watch?v=-xnTP4ZA1Nk

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.