blocking requirements for 20' tall 2x6 stud wall

[Skicat]

I'm having trouble finding info about the blocking for a 20' tall 2x6 wall. Obviously, I don't want the studs to run 20' without any blocking inbetween them. Everyone I've talked to seems to think blocking at mid-height is sufficient, but I can't find anything in a text or code about it. I would appreciate any help. Thank you.

 

[Ron]

Check section 3.7 of the National Design Specification for Wood Construction (NDS). This tells how to handle "columns" and effective length of the column. In this case, the stud is a column, obviously.

 

[boo1]

Assuming studs are have adequate support on each side to prevent buckling, (KL=1), and panels are applied vertically. Recommend full-width blocking installed at a maximum 8 ft on-center vertically with wood structural panel wall sheathing fastened per the code to one edge and either wood structural panel wall sheathing or gypsum wallboard fastened per the code to the other edge. This will provide a nailing surface for all panel edges and the shear flow.

Look at the finish system and make sure you don’t exceed the allowed defection. If straight walls are desired, consider Timberstrand or finger joint studs from Trus Joist or GP (straight 20’ – 2x6 will be hard to get). The 20’ tall walls I designed were eight inches thick

 

[boo1]

nice tall wall product link from TJ:

http://ilevel.com/literature/TJ-9003.pdf

 

[FSS]

Blocking will occur at the sheathing joints. The wall is sheathed, correct?

 

[dik]

and another really good publication:

http://www.cwc.ca/NR/rdonlyres/5B2929DA-FF5F-4FC4-89D5-6C40CF33D2B6/0/TallWalls07E.pdf

 

[RVSWA]

I believe fire blocking is required every ten vertical feet, but your sheathing should provide sufficient support. Out of plane wind loads are generally a concern with 20' high walls. King studs at openings need to be designed as well as a tributary stud spacing design. Using your load combination's and duration factors helps this calculation.

 

[Ron]

As RVSWA noted, you will need fire blocking. Under many of the exterior siding requirements now, the sheathing must be fully blocked as FSS noted. Considering full blocking and the sheathing, the studs would be fully braced in the lateral direction.

 

[rday]

With the code mandated fire blocking and sheathing on both sides I would not worry much about weak axis bracing.

At 20' I would have concerns about strong axis bending for for out of plane wind loads.

 

[boo1]

IRC Section R602.8 covers fire blocking, see link:

http://publicecodes.citation.com/ic....htm?bu=IC-P-2006-000002&bu2=IC-P-2006-000019

I don’t see any vertical 10 foot requirement for fire blocking.