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Re: IBC Fire Walls and Seismic Code

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Don't have any experience with the use of fusible links and wood, just steel.


From: "Paul Feather" <pfeather(--nospam--at)SE-Solutions.net>
Reply-To: <seaint(--nospam--at)seaint.org>
To: <seaint(--nospam--at)seaint.org>
Subject: Re: IBC Fire Walls and Seismic Code
Date: Wed, 26 Apr 2006 17:08:59 -0700

I can see your point for steel, but of wood type V? Multi story wood can burn and lose stability without the fire being directly adjacent to the wall, and it does not have to be hot enough to deform steel.

I am just asking. This is a new problem for me, and I need to come to grips with it fairly quickly. I will be downloading or purchasing all the references provided so far in the discussion and trying to self-educate. Being a CA engineer, we are still on UBC and have been insulated from this particular issue. I currently have some out-of-state projects where this is going to be a substantial issue.


Paul Feather PE, SE
www.SE-Solutions.net
pfeather(--nospam--at)SE-Solutions.net
----- Original Message ----- From: "Matthew Stuart" <pesepeng(--nospam--at)hotmail.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Wednesday, April 26, 2006 4:15 PM
Subject: Re: IBC Fire Walls and Seismic Code


This is a concern that many designers have. Of course it would be hard to imagine that a fire hot enough to deform steel would not in turn be hot enough to generate temperatures of 500 degrees just 30 feet away particularly when you are talking about connectors that are located in the upper portion of a confined space. FM provides criteria for calculting the magnitiude of lateral force associated with a collapsing steel frame due to a fire so it is possible to design connectors that fail at the maximum lateral load or walls to resist the same.

Matthew Stuart

From: "Paul Feather" <pfeather(--nospam--at)SE-Solutions.net>
Reply-To: <seaint(--nospam--at)seaint.org>
To: <seaint(--nospam--at)seaint.org>
Subject: Re: IBC Fire Walls and Seismic Code
Date: Wed, 26 Apr 2006 15:57:42 -0700

This brings up a question; what if the collapse initiates 30 feet away? The fire is not going to melt the bolts or ties, and the system will pull the wall over.


Paul Feather PE, SE
www.SE-Solutions.net
pfeather(--nospam--at)SE-Solutions.net
----- Original Message ----- From: "Stuart, Matthew" <mstuart(--nospam--at)schoordepalma.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Wednesday, April 26, 2006 2:47 PM
Subject: RE: IBC Fire Walls and Seismic Code


In my neck of the woods we call that a "fusible link" and I typically use Nylatron bolts. Heckmann also sells a metal break away connection but I prefer the Nylatron because it "melts" at a substantially lower temperature (500 degrees) than the Heckmann connectors.

Matthew

________________________________

From: Kestner, James W. [mailto:jkestner(--nospam--at)somervilleinc.com]
Sent: Wed 4/26/2006 5:35 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: IBC Fire Walls and Seismic Code


Matthew:

That is correct. For double walls, the required space is between each wall.

Weak link is a type of fastening detail that will release the firewall from the structure undergoing a fire condition.

Jim K.


-----Original Message-----
From: Stuart, Matthew [mailto:mstuart(--nospam--at)schoordepalma.com]
Sent: Wednesday, April 26, 2006 2:54 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: IBC Fire Walls and Seismic Code



For double fire walls the "space" for movement occurs between the two adjacent walls and not between the steel and the wall as is the case for the most part with the other examples.

I'm not familiar with the term "Weak Link", what does this mean?

Matthew Stuart

________________________________

From: Kestner, James W. [mailto:jkestner(--nospam--at)somervilleinc.com]
Sent: Wed 4/26/2006 4:11 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: IBC Fire Walls and Seismic Code


There are several ways to design firewalls:

Cantlivered
Tied
Double
Weak Link

With steel structures, you must provide enough distance between structures for the steel to expand without damaging the firewall(s). This distance varies 2 1/2" and 7 1/2".

I would think that the double firewall or tied firewall would be the common way to design in seismic areas.

The IBC gives little guidance to the engineer on how to design these firewalls. The best references are NFPA 221, FM, NCMA and Commentary M of the Canadian Code.

Jim K.

-----Original Message-----
From: Paul Feather [mailto:pfeather(--nospam--at)SE-Solutions.net]
Sent: Wednesday, April 26, 2006 2:00 PM
To: SEAOC List
Subject: IBC Fire Walls and Seismic Code


Under the IBC, the area separation walls from the UBC are gone, and the corresponding wall is a Fire Wall.

The primary difference is the ability of one side of the structure to collapse, without taking down the wall. The commentary clearly shows the diaphragm sheathing as discontinuous at the Fire Wall in Type V construction.

Question, how does this square with the seismic code provisions where all parts of the structure are to be interconnected, or a separation joint is to be provided? Are we now supposed to provide 4 to 8 inch seismic joints at all area separation walls, essentially breaking the building into multiple buildings?

Under the UBC Area Separation Walls it was permissible to have the sheathing extend through at the floor diaphragms, and the only problem was maintaining the rating through the assembly.

What are other people doing about this condition?

Paul Feather PE, SE
www.SE-Solutions.net
pfeather(--nospam--at)SE-Solutions.net



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