Live Load for Private Office Building?

[MJC6125]

I have a one story wood framed office building that I'm working on where the first floor is wood framed over a crawl space. I initially used 65 psf for my design live load with 125 psf in a couple storage room areas. I'm now wondering if I need to use 100 psf corridor loading anywhere. The building will be one company in the entire space, so there really isn't a public corridor to it, but there are hallways to get to the various personal offices. There also really isn't a lobby, but there's a reception area. 100 psf live loading seems like overkill because I can't picture this building with its current tenant ever being more heavily loaded than a residential home. However, I want to make sure I'm designing it correctly. Does 100 psf corridor loading need to be considered when the entire building is all the same office space?

 

[palk7 EIT]

Check with the building code it should specify what loading you should take into your calculation, in the area I am it's 100psf in corridor and for offices it's 100psf in basement and first floor.

 

[r13]

Apply the live load per permit application, whether it is residential, or office/light commercial building.

 

[skeletron]

I've always considered the 100psf corridor loading a function of the corridor being a "means of egress". This is related to fire safety. Fire safety requirements would be a function of the zoning/permitting on the building.

 

[phamENG]

It also may be worth a conversation with the owner of the building. Is this building going to be torn down when the company moves out, or will they renovate it and have a small boutique shop move in, or a restaurant, or something else? It's cheaper to put the 100psf floor in now than try to retrofit it in 15 years when the new tenant needs the higher rating. Of course, the ROI might not be there.

I agree with skeletron - 100psf is for means of egress. All of those people spread out in the 50psf area are going to come running together into the corridor to exit the building. I'd do 100psf in the corridors and any areas where you could have a "gathering" (company staff meeting, Christmas party, etc.).

 

[jayrod12]

Where I practice it's 100psf everywhere for offices in the basement and ground floors. 50 psf on floors above ground.

 

[lsmfse]

We use 85 psf for office building and when you add 15 psf partition load you are at 100 psf, so corridors can be located anywhere.

 

[MJC6125]

Interesting. I didn't realize that 100 psf LL was specified for offices in the basement and ground floor in some places.

Jayrod12, for upper floors do you design the whole floorplate for 50 psf or do you use the 80 psf loading for the corridors above the first floor? If you do use the 80 psf, do you only apply that in public common space corridors (i.e. between stair and elevator cores) or do you also apply that 80 psf loading in the hallways/corridors within a tenant space?

 

[jayrod12]

We actually use 100 psf for higher level corridors as well.

 

[MIStructE_IRE]

Our code looks for 3kPa + an allowance of 0.5-1.0kPa for moveable partitions. However many of our clients, and their insurers, look for 5.0kPa.

So I would recommend confirming with your client as well as checking what the code says.

 

[Agent666]

As another comparison point, we are required to use a minimum of 3.0kPa live load for general offices in New Zealand and 4.0kPa for corridors/stairs. Similar to MIStruct_IRE, there might be anywhere from 0.5 to 1.5kPa super imposed dead load (SDL) on top of that for partitions, furnishings, services, ceilings and the like.

To accommodate future changes, you might sometimes use 4kPa throughout, I've certainly done this before on structures such as hospitals that you might expect to be reconfigured several times over their useful lifetime.