This is so sad to see. :(

Re: This is so sad to see.

It was a low angle Carport type cover with a center mount Is there any doubt that it would fail at some point with snow load on one side that would pull it out of balance ??

Re: This is so sad to see.

I have never seen such bad fastening on a structural column. If just in compression it may have been ok. 6 @ 3/8" anchors only 5" into the concrete was a recipe for failure. Either the engineer or builder is in a lot of trouble. Hope their insurance was paid up.
Ned

Re: This is so sad to see.

I agree the anchor bolts are entirely unacceptable, someone saved a buck and it will be up to the courts to figure out who pays for the fix. The tough part is that even if the bolts were designed correctly, the high snow loading may case some other part of the structure to fail due to excessive load. If the snow was wet, it easily could be over 30 PSF and many structures outside the snow belt may be designed for less.

The region I live in northern NH is a "black zone" for snow loads. Generally there is a loading map in the code books used to determine maximum ground snow load. Due to the potential for high snow loads in the area, the local towns have to establish snow load. My house is next to the town with the highest snow load in the state which is 110 lbs per square foot ground snow load (my town is 95 psf). There are factors used to reduce this amount for roof snow load but generally it means that houses built to code have 12" on center rafters with a couple of inches of extra depth. Many contractors from outside the area design to 40 PSF and since most of the towns do not inspect residential homes many houses get built with less than code design. I used to work in an local industrial plant that had been around for 100 plus years, many flat roofs were designed for 10 PSF. The theory was that the building were heated with no insulation so the snow would melt before the roofs loaded up. Unfortunately over the years some buildings ceased being heated and some had new roofs installed with insulation, most survived. My experience is that structures rarely fail due to the design as much as in the details. I would expect that the structure in the video was doomed from the day it was built due to either poor design or shortcuts by the contractor, which should in theory have been caught by the inspector. Unfortunately with concrete, its easy to bury the details.

Re: This is so sad to see.

BB. wrote: »

Running the video and I see that both the bolts pulled from the concrete and (it appears) other concrete "posts" may have snapped at ground level (possible that the earth failed--could not see due to snow).

Those do not appear to be anchor bolts. Those are regular carriage bolts.

My house is set on a concrete foundation. That foundation has a lot of rebar in it. Anchor bolts are in an 'L' shape. The 'L' hooks under the rebar, and is twist tied to the rebar before the concrete was poured.

Upward force on the anchor bolt transfers that force to the rebar in the concrete.

Also those carriage bolts look to be only about 8 inches long. My anchor bolts are over a foot long [I do not recall their actual length, 14" maybe?]




They do market concrete drill bits, that you can use to drill a hole into concrete, then you could screw a carriage bolt into the hole. But that does not make it an anchor bolt. That is simply a bolt screwed into concrete for light weight use; like pipe hangers. But never for anything structural.

Now they do get away using carriage bolts for street lights. But how much weight is on a street light. And I think there are other laws that require a street light to break-away easily when vehicle smacks it. Perhaps the contractor was thinking that those poles would be holding the same weight as a street light.

Re: This is so sad to see.

SolarPowered wrote: »

According to California DSA requirements the bolts have to be 1-3/8" J bolts tied into the rebar. Those were some 3/4 dowel pin allthreads. I wouldn't be surprised if the contractor that built that system was to be sued, because contractors have to warranty that work for 10 years.

'J' bolts, I guess I forget the name for them

When I saw that video, the first thing that jumped out at me was those are the wrong bolts, and where is the rebar.