firewall structural loads

huangyhg

firewall structural loads
what structural loads are others using on there firewalls?  how are others designing their firewalls?  the firewalls must maintain structural stability when the building on the other side of the wall collapes. there seems to be 3 methods: 1)free standing wall cantilevered from the floor(neither bldg is tied to the wall), 2)double wall tied back to it's adjacent building, and 3)integral wall supporting (and tied on) both sides and able to withstand the collapes on one side. it seems, most engineers use wind and earthquake loads as their structural loads.  is this correct?  i'm interested in what others are doing and i'm interested in any references.  thank you.
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my understanding of a firewall is that it is not necessarily a structural wall but rather a partition to slow the spread of fire. the wall should be constructed of materials to provide a desired rating (1 hr, 2 hr, etc.)
to require a wall to maintain its stability when an adjacent building collapses seems like a ridiculous requirement if the building is more than a few stories. if it is a load bearing wall, i would not design it different from a structural standpoint and use all applicable loads (i.e. wind, seismic, etc.)
good luck.
a firewall and fire separation are two different beasts.  motorcity is refering to a fire separation which can be structural or not.
my understanding is the firewall must be able to withstand design loads without the support of the other building.  as far as i know this includes all the normal structural loads used for calcs in your area.
this is one of those areas that the ibc does an excellent job of saying the firewall must remain standing but a extremely poor job of giving any criteria or guidance. i would suggest using fm, nfpa and the canadian code for guidance.
obviously, the wall must meet seismic loading, whether exterior or interior. if the wall is an exterior wall, obviously it must also be designed for wind load also. if it is an interior wall, the design criteria is not spelled out. i have seen some engineers use the loading for interior partitions 5 psf. if i recall correctly the canadian code recommends 10 psf ultimate. it is thought that this provides for thermal shock to the wall and other forces. i know of no studies where these forces have been verified.
i believe the philosophy of not designing for full wind load on an interior firewall is that the wall must remain standing under the "fire conditions". afterward, it can be braced, strengthened or re-built.
it would be great to get a building official to give us an official interpretation.
nfpa 221 provides some information and design criteria for fire walls and fire barrier walls.  you might find that useful.