Standing Seam Roof as Diaphragm 1

[BadgerPE]

Hey all,

Came across this ICC report when looking for info about SSR being used as a diaphragm. The allowable shear values are quite low, but there is some capacity, at least for VP SS.

 

[MiketheEngineer]

IMHO - not too many people try to use SSR for a diaphragm. Plywood, then SRR - works well.

 

[msquared48]

Or Horizontal X-bracing in the roof.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[JedClampett]

I've thought about this, but one problem is that the supports for the SSR need to be pretty close together, so unless you want to space your purlins pretty tight, you need a plywood, nailable insulation or metal deck roof anyhow.

 

[marinaman]

Its been my experience to not rely on SSR for diaphragm capacity.....especially if I was designing a new building.

I guess I take two positions on this......

1. Based upon my experience, I would not rely on SSR for my diaphram capacity for a new building....where I can drive the structure to be whatever I want it to be.

2. If I am analyzing an existing building, where its already there and been there for awhile, I may would try and work with the structure that is there and take advantage of every existing element that exists, rather than just automatically discounting the capacity of any existing SSR.

 

[hokie66]

Standing seam roofing is to make the building watertight, not to brace it. No other type roofing would be relied on for bracing, so why SSR?

 

[paddingtongreen]

The architects would have us believe it's another form of metal roof deck, same thing only it looks better.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[BadgerPE]

Just for the record, I only posted this for the evaluation of existing buildings that may be lacking a lateral force carrying system. I would rather not use it for a diaphragm on a new building either.

 

[focuseng]

look up post frame buildings and you will see that light guage metal roofing is used extensively. There is lots of data and design values to support this I believe the resources you will need by asae are:

ep588: Load tests for metal clad wood framed buildings
EP484: diaphragm design of metal clad wood framed buildings

look up postframe.org

MAP

 

[RFreund]

I think there needs to be a clarification if this is referring to a 'true' standing seam metal deck, which from my understanding only clips over overlaps at panel sides. So that the panels can slide past each other. Or a light gage (29 gage) metal deck which is fastened usually via screws if I'm not mistaken to the roof framing.

EIT

http://www.HowToEngineer.com

 

[focuseng]

Ah yes... "Standing Seam" roof would not fit the category I mentioned. Sorry.

I would not put any stock in the capacity of a fastening system where it is designed for movement between parts to be used as a diaphragm. Definitely a no-no. Compound this with the need for it to be value priced and the SS roof installed is never the one specified. Nobody will check with the engineer about this to make sure it is OK to provide an alternate.

 

[focuseng]

Crackerjack47, if you intend to justify an existing SS roof installation using the attached code evaluation report then you would have to Prove that it is installed using the exact methods, tools and materials identified in the report. Otherwise, it would be pure speculation as to the lateral capacity you could expect performance for. Is that what you are asking? This report outlines a very intense installation system (proprietary) which is not typical to most SS roof installs.