Occupancy Loading on Outdoor Balcony in High Rise

[rsbmusicguy]

Hey all,

I am working on calculating the capacity of an outdoor, reinforced concrete cantilevered balcony on a high rise. Ultimately I will need to post the balconies based off of an allowable occupancy and an allowable storage load....

I have calculated the capacity of the balcony and therefore I am not having any issue with the allowable storage. However, is any of you more knowledgeable when it comes to occupancy loading on a balcony according to the IBC 2018? I have come across a rule of thumb for 5-7 ft^2 per occupant (don't know where this number was referenced) but I have been struggling to find an occupancy factor in the IBC to calculate the number. By inspection, it appears based off of my allowable capacity that the occupancy will be controlled by egress and the IBC.

Any help would be great, thanks!

RSB

 

[XR250]

Isn't it just the same as the interior occupancy load?

 

[rsbmusicguy]

Yes however I do not know what the interior occupancy load factor is, this is where I am getting hung up.

I am almost certain that this will be controlled by egress, currently the section can take 1520# along the 6.75 long span before it yields. This is equivalent to a 225 pound person per foot or a 450 pound person per 2 foot width therefore the occupancy factor should control but I do not know where to find this number in the IBC 2018.

RSB

 

[JLNJ]

You don’t guess at how much people weigh and how much space they take up.

You need to look at the Live Load provisions in the code. If you don’t know how to do this, then you need to seek help from a structural engineering professional who understands the code and how to apply it.

If the balcony wasn’t designed to be code-compliant, then you have a whole other set of problems on your hands.

 

[rsbmusicguy]

When I said 225 pound per person per foot, I am implying a 225 plf Live Load is permissible at this section before yielding. I originally analyzed it for 100 psf which is the maximum for my situation per the IBC 2018, the balcony is passing consistent with the IBC load combinations; however I am required to indicate the maximum live load at the request of the client.

I am not concerned with the loading but a provision in the IBC that specifies maximum occupancy with respect to egress in the building.

I will be signing and sealing these documents as a professional structural engineer.

RSB

 

[jayrod12]

I wouldn't approve anything above the code level loads, even if it calculates out. Maximum 100 lbs per square foot. In terms of number of people that means, that's more an architect question and I believe it has to do with door width typically.

 

[rsbmusicguy]

Thanks Jayrod, you make a good point and I will definitely consider that.

Yep - I am playing architect today, I may have to reach out to an architect friend and see.

Appreciate the help!

RSB

 

[hotmailbox]

From another recent eng-tips post

 

[EZBuilding]

Per the Florida Building Code...

5. Balconies and decks

1.5 times the live load for the area served. Not required to exceed 100.

 

[rsbmusicguy]

Hotmailbox - that is awesome! I love to see these types of things.

EZBuilding - this is what I am currently analyzing with, thanks for the help.