Tag Archives: construction codes

Bracing Site-Built Trusses for Lateral Loads

Bracing Site-Built Trusses For Lateral Loads

Reader in SHINER writes:

I am building a gambrel style barn, 30×80, in two directions, in plan view, it looks like a cross. I am building the trusses based on an LSU publication, giving sizes of structural members, etc… I have built several structures before, not a gambrel style barn though. My Question, Guru, how do I brace the trusses for lateral/wind/racking/diagonal loads? I want to do an exposed ceiling of 2×10’s T&G, and am worried about how to brace the trusses so they don’t fold over like a deck of cards during and after construction. Surely the nails don’t provide all the lateral bracing? I’ve seen too many leaning barns over the years to know that nails alone don’t provide sufficient wind load protections. How are the trusses braced, one to the next, so they don’t fold/roll over? Your help is so appreciated, Thank you.”

Mike the Pole Barn Guru writes:
Even with my decades of truss industry experience, I wouldn’t begin to think of field constructing 30-foot span gambrel trusses. 

I did review LSU’s “truss” design (these are actually rafters not trusses), it is from 1988 and includes this disclaimer:

“This site makes available conceptual plans that can be helpful in developing building layouts and selecting equipment for various agricultural applications. These plans do not necessarily represent the most current technology or construction codes. They are not construction plans and do not replace the need for competent design assistance in developing safe, legal and well-functioning agricultural building system. The LSU Agriculture Center, the Mid-West Plan Service, the United States Department of Agriculture and none of the cooperating land-grant universities warranty these plans.”

Several problems – no design roof or wind loads are incorporated in their design and design values for Southern Pine lumber were down graded as much as 30% in 2012 https://www.hansenpolebuildings.com/2012/06/southern-pine/

Any permanent roof truss/rafter bracing system should be developed only by a Registered Professional Engineer. Given LSU’s information is highly out dated, should you wish to continue upon this path, I strongly urge you to reach out to a competent Registered Professional Engineer to design a structurally adequate system, including a permanent bracing system you can rely upon.

Building Codes: Constructing over minimum standards

‘I want to see people build past minimum (code) standards’: Mike Holmes

In a June 29, 2011 copyrighted article in Postmedia News, Mike Holmes says, “Anyone who knows me knows I talk an awful lot about building code. The code is a minimum acceptable standard for the construction of a building. It’s also a living, changing document that is adapted every few years to ensure it keeps up with major changes to the ways buildings are built and the materials that builders use in construction.”

Holmes goes on to say, “Even if they are minimum standards, codes matter. I’ve said before that I’m not a fan of people who build to code because the building codes are minimum standards. I want to see people build past minimum standards, so that every homeowner has the safest possible living environment.”

Don’t just build to minimum code standards, plan to build above and beyond them!

In the case of pole buildings, we thoroughly agree with Mike Holmes. Sadly, we in the United States have many jurisdictions where building permits are either not required at all, or are granted without a thorough plan review and field progress inspections.

One of the largest post frame builders in the country, designs their non-permit required buildings to their own “robust” standard. To upgrade these buildings to meet code requirements involves a significant increase in price!

I am ever amazed, dumbfounded and totally appalled at clients who, after being advised of their wind and snow requirements, ask me, “What would it cost to build to lower values?”  Is throwing safety right out the window really worth saving a few bucks?

What most clients do not realize is that increases in building load carrying capacity often result in very minimal costs. A building with a low risk of human injury or death in the event of a failure (IBC Category I), is designed for the maximum design loads to be exceeded once in an average 25 year period. An upgrade to Category II doubles this to a 50 year period, with a net effective increase in snow load capacity of 25% and wind capacity by 15%.

Concerned about the lifespan of your new pole building? An increase of 10 pounds per square foot of snow load and 10 miles per hour for design wind speed means your building might very well be the last one standing, when it comes to a catastrophic event.  Don’t just build to minimum code requirements, plan to build above and beyond them, and sleep well at night knowing when you wake up, your building will still be there after a stormy night.

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