Garage collapsed

[e57]

I agree the big stacks of drywall worry me sometimes.

Last year I was in a new high rise that was getting a new gypcrete floor in one unit - they had to only do it in sections, and only bring up enough for each section in small loads for each - and spread it out, doing because the building was worried about point loading on the floor - which was the ceiling of the unit below.... THEN go figure they brought the rock up - put it ALL in the living room, and flexed the concrete enough to crack the paint downstairs....

Anyway - I found an article on this topic.
And from what I can tell... (here ~) CA wants the loads of snow and parking to also be combined with percentages of siesmic and wind loads? :roll:

 

[wwhitney]

CA wants the loads of snow and parking to also be combined with percentages of siesmic and wind loads? :roll:

This is standard practice with multiple intermittent loads (e.g. snow, wind, and earthquake). It is unlikely that you will get peak loads from each source simultaneously. So instead of adding up all the loads, you take one peak load and a reduced load from the other sources, something closer to an "average" load from that source. I use the term "average" loosely.

Cheers, Wayne

 

[e57]

This is standard practice with multiple intermittent loads (e.g. snow, wind, and earthquake). It is unlikely that you will get peak loads from each source simultaneously. ~
Cheers, Wayne

Unless there is a snow storm, and an earthquake and it is Xmas shopping time... Electrically - I always design for Xmas. (the worst case scenario is a bazzion extra lights, and every appliance/equipment running, plus some other new unexpected item/s.)

 

[Jim W in Tampa]

One thing is for sure here and that is someones insurance will be going up or droped. Average or not this garage has millions in damage and loss of use. Hope we get posted the outcome or in other words who has the better lawyer. Just might end being the electrician LOL

 

[wwhitney]

Unless there is a snow storm, and an earthquake and it is Xmas shopping time... Electrically - I always design for Xmas. (the worst case scenario is a bazzion extra lights, and every appliance/equipment running, plus some other new unexpected item/s.)

Let me expand a little bit more. In structural engineering with intermittent loads, there is sometimes no real "worst case" scenario. It could snow for 30 days straight and accumulate 30 feet of snow, a massive wind storm with 200 mph winds could hit, an enormous earthquake could rupture 1000 miles of fault, or flooding could be 10 feet above anything ever seen before.

So instead what is usually done is to set an acceptable level of risk. You try to model the pattern of loads presented and find the largest load that can occur with a selected low level of frequency. E.g. what is the biggest earthquake that has at least a 2% chance of happening over the next 50 years? That load, after suitable factors of safety, becomes your design load.

In the case of simultaneous load patterns, you are still interested in the same chance of occurence. The chance of seeing the "2% in 50 years" snow load coincide with the "2% in 50 years" earthquake load is only 0.04% in 50 years (although I don't think 2% in 50 years is the usual standard for snow loads). So if you are considering what snow load is likely to be coincident with your "2% in 50 years" earthquake, you use a reduced loading.

Hope this helps.

Cheers, Wayne

 

[e57]

Let me expand a little bit more. ~~~


Hope this helps.

Cheers, Wayne

Oh I get it... But depending on where and when you are - in that 2% in 50 years coincidental oops may or may not happen - I just don't wanna be in the building for it....

Say you were in Tahoe - show on the roof is roughly a 20-30% chance through the year - but only for a few months at a time. A small earthquake every once in a while, a big one eathquake may happen only once in a blue moon... A big windy storm - every 3rd day of winter... IMO the chances of coinidental occurrance get higher than say somewhere else. But still I don't wanna be there....

 

[joeatrsp]

structural loads

structural loads

According to our structural engineer, parking garages are only required to be designed for 40 pounds per square foot, and that's only about 30" of snow.

Steve

40 PSF is the code minimum uniform live load for parking garages. That is the load factor that addresses people and vehicles.

Snow load is an additional load that will vary depending on your locale. In addition, state codes may require structural design to address drift loads, e.g.: where snow drops from a high roof to a low roof and creates a buildup of snow much greater than the average depth.

Using my location, Minnesota, as an example if I were looking up loads for the top deck of a parking garage I would have: 40 PSF live load + 40 PSF snow load = 80 PSF. Drift loads could range up to 120 PSF.

Judging by the photos, I wouldn?t attribute this to a design flaw. I?m looking at that huge pile of snow and thinking it got piled up in one structural bay of the garage and overloaded it. This thread?s author says he?s in Baltimore ? which leads me to guess that the person doing snow removal from this garage had a lot more snow than they knew how to handle properly. Word to the wise: Don?t pile it up on the top deck. Dump it over the side one bucket at a time ? just be aware of what you?re dropping it on.

 

[mivey]

...just be aware of what you?re dropping it on.

And have your camera ready.

 

[e57]

Dump it over the side one bucket at a time ? just be aware of what you?re dropping it on.

While back skiing in Calgary (Well Lake Louise...) They had a hopper at the hotel they would dump snow into. A bunch of pipes ran though it - apparently hooked up to live steam? Melted each load just like that.... Simular to this but permanent out back of the hotel. IMO better than the big piles in the parking lot, or dumping on some pedestrians head...