Congrats to JLC for new Policy on Archived Publications

[Frank Woeste]

I was pleasantly surprised to learn that archived articles, Q&A, and other areas of the JLC archives are now open to search and download w/o a fee. This step will open up decades of good work by the JLC to the entire world.

Unrelated to the JLC website changes, I am wondering how many Forum members have installed MPC wood trusses or light-guage steel trusses spanning 60-ft or greater??

The 2009 IBC has special provisions for the installation and bracing (and inspection) of trusses spanning 60-ft. and greater. You can read code language here:
ICC Special Inspection for trusses 60ft and greater.pdf


We have written on the subject here:
http://www.kenilworth.com/publicatio.../files/54.html

Frank Woeste
Professor Emeritus
Virginia Tech

[jimAKAblue]

I couldn't figure out how to read that link. I couldn't find a suitable balance on the zoom button.

I've set 80' wood trusses. They were 6/12. We essentially "temp" braced them by installing most of the required permanent bracing as we went.

[Frank Woeste]

jim:

The site is a bit tricky--once you click on the area you want to read, you need to wait a few seconds for the program to bring the area into proper focus. If you, or others, would like a clean copy of the article, please email me (fwoeste@vt.edu) and I'll send it. The code change is by far the most significant change I have seen for trusses in my career.

Here’s a one paragraph summary:
Upon adoption of the 2009 International Building Code (IBC) by state codes or local jurisdictions, the Owner of a project with metal-plate-connected (MPC) wood trusses spanning 18 m (60 ft) and greater (churches, schools, commercial, retail, etc) will be required by code to engage a registered design professional (RDP) to:

1. Design the temporary bracing for the MPC wood trusses,
2. Inspect the temporary bracing for the MPC wood trusses,
3. Design the permanent bracing for the MPC wood trusses, and
4. Inspect the permanent bracing for the MPC wood trusses.

The parts 1., 2., and 4. are new.

Frank Woeste
Professor Emeritus

[jimAKAblue]

Thanks for the offer Frank but I don't really need that type of info any more. I haven't framed anything in almost ten years now. And, you basically cleared everything up for me with the 1.2.3.4. thingy.

I fully understand why there would be serious concern about handling MPC trusses that are 60' or longer. They are like giant pieces of spaghetti flopping around in the breeze when they are hoisted and handled. The metal plates can easily be compromised. And, the tendency for collapse while getting them set is enormous.

When we set our 80'ers, we took care to get both the bottom and top chords solidly temped and we also fell back and installed all lateral bracing, with diagonals as we proceeeded. I was the lone ranger walking the top chord and I devised a rather clever plan to install a substantial amount of the permanent lateral bracing while also being ready to receive each truss as it came in.

[Ohiobuilder]

Almost all of our homes use Trusses but never have we set anything at 60ft or better. Thats a really big truss.

From what I understand truss bracing in general (for all spans) is going to be effected in a big way by the code changes.

The state code representative at our HBA is thinking the changes coming at the first of the year are going to challenge the building officials as well. We build in several counties and towns that all have their own building departments - they each have their hot buttons.