Funny thing about the 2009 IRC wall bracing requirements. There are a LOT of options to use with different types of hold downs, straps etc. Guess who was on the committee to rewrite the wall bracing section????? The engineer for Simpson Strong Tie.... Imagine that!!!
Simpson has a great web site for determining how much wall bracing is needed.
The classes I've been too haven't been anything but "here is what the code says"! They don't teach you how to figure it out! Our AHJ was the first to adopt the 2009 IRC in the Dallas Fort Worth Area so I had to learn it on my own. I spent around 6 months and had the engineer with Simpson come out and sit down with me. Now I teach others on how to determine how much where when what and all that stuff.
Really most residential structures are going to be okay IF they are not more than 60' in any direction. Over 60' and all kinds of things kick in! With the 2009 IRC structures can be up to 68'. Not because they increased the length from 60' to 68' but because in the 2009 IRC you can "float" the braced wall line by 4' and still be considered the same wall. So if you have an offset of 8' on walls, you can move the braced wall line to split the wall and if there in not more than 4' to each wall then you can use the 2 walls to create 1 braced wall line. It helps the designer but it wreaks havoc on the plan reviewer.
A lot of AHJ's are not requiring braced wall line diagrams on the plans however this is all new to all of us and the engineers, architects and design professionals do not understand it either. Lots of mistakes on the plans due to not enough knowledge to do it correctly. What I have seen is they just throw a lot of bracing that really isn't required thus costing the builders and in the long run the homeowner paying additional costs for a design that wasn't needed.
We required a braced wall line diagrams, indicating where the braced wall lines are located, along with panel location, showing distances between panels, what type of wall bracing panel, amount required, amount provided. If any interior wall bracing is required they have to indicate everything on the interior walls also what type of anchoring they are going to provide for the bottom plates. Also if interior wall bracing is required they need to indicate the location of the panels on the foundation plan also.
As far as inspection we look at the wall bracing plans at the foundation inspection, framing inspection, and drywall inspection to verify compliance.
It's a lot for the builders to accept but it's just one of those things that is necessary.......
The 2012 has a simplified version of the wall bracing requirements. If you can draw a box around the structure that is not more than 60' then you can keep it simplified and go with the "old" rules. When I say old rules I mean almost identical to the 2003 IRC requirements.
Sorry to ramble on but this subject is a passion of mine...........
