Hotel Corridor Live Load 2

[slapjack]

On a typical over-night hotel, rectangular in shape with rooms on each side of the building and a long corridor down the middle, which design load should be used for the corridor?

(a) 40 psf - Private rooms and corridors serving them

or

(b) 100 psf - Public rooms and corridors serving them

The rooms are individual private rooms. However, the corridors are public areas where anyone can access. Also, keep in mind, these corridors would be the main method of exit should there ever be an emergency.

Thanks!

 

[271828]

Yet I type it again, LOL:

If this isn't ASCE 7-05's "Private rooms and corridors serving them" = 40 psf then I don't know what is!?!

 

[swivel63]

a corridor within a unit.

has someone asked a building official this yet?

 

[271828]

swivel63, you sure have a hard head to see it that way, LOL! Just giving you a hard time...

I think that would be called a "hallway."

From

http://www.webster.com:

"Main Entry: cor·ri·dor
Pronunciation: 'kor-&-d&r, 'kär-, -"dor
Function: noun
Etymology: Middle French, from Italian dialect (N Italy) corridore, from correre to run, from Latin currere -- more at CAR
1 a : a passageway (as in a hotel or office building) into which compartments or rooms open b : a place or position in which especially political power is wielded through discussion and deal-making <was excluded from the corridors of power after losing the election>"


Besides, ASCE 7's language seems to clearly mean a corridor between rooms. "Private rooms and corridors serving them." Why would an interior hallway "serve" rooms within the same unit?

And to answer your question, I think we all asked DonPhillips and he said 40 psf!

FWIW, I review structural plans for 3 jurisdictions and I would say 40 psf also.

 

[swivel63]

they're synonyms

http://dictionary.reference.com/browse/hallway

"a corridor, as in a building"

"an interior passage or corridor onto which rooms open; "the elevators were at the end of the hall"

the difference IMO is the usage.

why would do balconies have higher live loads as opposed to the interior of a unit? and to add to that, why would a balcony (which is a private area) have a higher live load as opposed to a corridor of this sort (which is a public area).

this is the where the engineering judgement comes into play.

 

[271828]

Swivel63, it doesn't hurt me if you believe it's 100 psf, LOL. I still say it's not necessary.

Balconies have higher LL than the interior because it's very likely that during the considered 50 year interval there will be an event in which the entire balcony is crammed full of people. They collapse from time to time during parties, etc., so this probably motivated the writers of ASCE 7. It's further proof that extreme loading is likely on a balcony.

As for corridors, it takes an average 160 lb person at 2' o.c. to make 40 psf. Even during a fire evacuation, this seems completely far fetched to me. To get 100 psf, it would take a 160 lb person at about 15" o.c. over a non-trivial area. Not sure how people could possibly be evacuating at 15" o.c. They're still moving toward the stairs while they're in the corridor.

Pre-emptively answering the next volley: Stairs are different from corridors. It is likely that during a fire, tornado warning, etc., that everybody in the entire floor could cram themselves onto the stairs and landings. By the time they get to the stairs, they've all funneled into that small area and perhaps stopped there. 100 psf still seems very difficult to achieve even there.

 

[swivel63]

no one's trying to hurt anyone, this is a discussion among engineers.

however, it's also likely that during moving, evacuation events that a corridor of this type will experience heavy loads as well. maybe not 100, but quite possibly higher than 40. balconies (in HVHZ) have a 60 psf live load and public corridors are commonly designed for 80 psf (in HVHZ) with stairs designed for 100. and keep in mind, during that moving they're imparting vibrations from impact of all the moving feet onto the floor slab that is not common in private residences.

40 psf will probably very rarely if at all ever be experienced by a residential unit, but we still design for it as a minimum. even in a room full of people with furniture and the whole nine, it probably won't even come close to 40 psf. in a two bedroom apartment, with about 1500 sf, the total load that that apartment is designed for will come to 60 kips, but do you honestly think 60 kips will ever find it's way into a unit that small? but yet and still, it is common knowledge that this is the absolute minimum design load that we use for that type of application.

 

[271828]

"no one's trying to hurt anyone, this is a discussion among engineers."

Very true. Have a good weekend, what's left of it!

 

[WillisV]

swivel63 - regarding if anyone has asked a building official, I posted the response from ICC on this exact question earlier in this thread (see somewhere above).

Bottom line: ICC says if the corridor is only serving private units then the design load is 40psf. That meets the code. Anything above this is the discretion of the engineer.

I have run into one building official who interpreted it to mean hallways within the unit as you alluded to earlier, however he backed down from this stance after some discussion.

 

[miecz]

I should think that if a corridor is serving a single private unit (a rare situation), then 40 psf applies. If a corridor is serving 50 private units, I would be inclined to use 100 psf.

WillisV-

When you asked the ICC, was it clear whether the corridor served a single unit vs. multiple units?

 

[JAE]

jmiec - I think the 40 psf is the correct interpretation here, but as the code is listing minimum standards, it sounds very practical and pragmatic to use your suggestion of 100 psf with the 50 unit situation.

 

[WillisV]

jmiec...the question I posed to ICC was the exact question shown in my previous post in this thread (2 May 07 19:37 ). It was pretty clearly worded to apply to the main corridors of hotels and multi family residences serving multiple units and ICC's response left little room for question.

As I said in the previous post and as JAE just reiterated, this is a code minimum and it is up to the discretion of the engineer to exceed the code minimums if he/she thinks it is warranted.

 

[miecz]

WillisV-

Yes, re-reading your original post, it's quite clear. Often, when something like a code requirement goes against my judgement, I need to read it a few times. Thanks.

 

[swivel63]

it must be different in different regions of the country, but i just checked the FBC '04 HVHZ section. it says the same thing in our live load section, but there's the HVHZ caveat at the end of the chapter. the wording is as follows:

"paths of egress servicing 80 psf or less - 80 psf"

"paths of egress servicing 80 psf or more - 100 psf"

i would define that corridor as a path of egress since

 

[swivel63]

so S.K. Ghosh (he's a code consultant) just gave seminar on the IBC as well as the ACI for our SEA today. i guess he's 318 buddies with my boss, so i pitch this question to him.

first thing he asks is whether or not the corridor is open to the public, or if unit owners are the only one's who have access.

if it's open to the public and an egress path, then the proper design load is 80-100 psf....if it's closed off to the public, then you might be able to get away with 40 psf. but he still wouldn't touch that 40 psf with a 10 foot pole.

oh yea, don't shoot the messenger LOL

 

[271828]

Bang bang bang bang, oh wait, you requested that we not shoot the messenger, sorry.

So Mr. Ghosh was in a CYA mood today, eh? LOLOLOL.

I have a buddy on the ASCE 7 committee and I'll see what he says. I think we could ask 10 of them and get various answers.

Perhaps one of those guys should bring this up during their next meeting and get the language clarified.

Actually, before about a week ago, I would've thought that the language was about as clear as any code language in existence, but apparently not.

 

[271828]

Swivel63, please don't return fire at the messenger, LOLOLOL.

I saw another "guy who should know"-type this morning and asked him the same question and he said he has typically used 100 psf, but 40 psf is the obvious intent of ASCE 7 now. I won't name names, but he was in private practice for 20+ years, has a PhD, and has been very active in ASCE 7.

I asked one friend who works for a NYC firm and he said they just use 100 psf period for a corridor. No reason given beyond that it was company policy.

I asked my buddy who's on the ASCE 7 committee and he said he wasn't sure.

He submitted this question to Jim Rossberg, but haven't gotten an answer yet. I think the question is fairly worded, slightly stacked toward 100 psf IMO.

Say you have a multi-story hotel. Typical layout with one long corridor with rooms on both sides. Egress stairs at each end of the corridor and in the middle. Only private rooms on the floor, no other kind of rooms such as conference rooms.

What’s the live load in the corridor per ASCE 7-05?

Is it 100 psf because the corridor is open to the public and it’s an egress route?

Or

Is it 40 psf because the corridor falls under “Private rooms and corridors serving them.” ???

If the answer is 100 psf, when can the 40 psf be used? Ever, practically speaking? It takes an average size person at 15” c/c to make 100 psf, which would seem to me to be impossible over a significant area.

 

[271828]

Swivel63, I have no idea what Rossberg will answer, but I think the bottom line is this that one could use either and defend it.

I think if we asked 10 gurus, we'd get 6 voting one way, 4 the other, or maybe 5 and 5.

One could defend 100 psf as has been done.

My defense of 40 psf:

1. ASCE 7's wording is obvious. I would've stopped there before this thread.

2. It would take an average person at 15" each way, on-center to make 100 psf, an impossibility for the given situation, IMO. 40 psf is an average person at 2' each way, on-center. Most people are about 2' wide. I have no gut whatsoever and I'm about 12" front to back. That leaves 12" of space between people standing shoulder-to-shoulder (assuming they all have no beer gut, LOL) which seems about as close as is reasonable to assume during an evacuation.

Try reasoning out how you can get 100 psf!? I guess you could get that if you lay people down and stack them 2-3 deep over the entire area, LOL.

 

[swivel63]

how about a grenade?

LOL

you're right...ask 10 engineers, get 10 different answers.

my defense for the 80 psf is as follows

5 May 07 18:52

7 May 07 9:47

8 May 07 20:00

i'm lazy today, lol