CsubL value for headers
CsubL value for headers
(OP)
I am wondering if there is a general consensus regarding applying the lateral stability factor for wood headers in a wood stud wall.
opinion 1. Assume = 1 because the ends are rotationally restrained and the stud wall above the header provides lateral restraint.
opinion 2. Calculate specific value <= 1.0 based on ends rotationally restrained but header not laterally restrained.
a. Loading assumed uniform for most cases
b. In some cases, concentrated load due to girder truss etc.
I am leaning toward opinion 2 because typical header is at least 2' below "true" lateral restraint provided by floor or roof structure.
opinion 1. Assume = 1 because the ends are rotationally restrained and the stud wall above the header provides lateral restraint.
opinion 2. Calculate specific value <= 1.0 based on ends rotationally restrained but header not laterally restrained.
a. Loading assumed uniform for most cases
b. In some cases, concentrated load due to girder truss etc.
I am leaning toward opinion 2 because typical header is at least 2' below "true" lateral restraint provided by floor or roof structure.





RE: CsubL value for headers
RE: CsubL value for headers
RE: CsubL value for headers
So for 4x headers greater than 4x8 it depends on the end connections.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: CsubL value for headers
The usual headers are 2 - 2 x 6 to 2 - 2 x 12. Less frequent are triple 2 x's in some cases where the wall studs are 2 x 6.
Garage door headers (16' door) are 2 - 2 x 12, 3.125 x 10.5 GLB to 3.125 x 16.5 GLB in most cases.
4 to 8 - 16d nailed thru the first king stud into the end grain of the header. That's the rotational restraint.
Is that adequate for end connection in the NDS? Seems so to me.
That NDS info is useful. Never was aware of it.
RE: CsubL value for headers
2 - 2 x 6, span = 8' CsubL = 0.99
2 - 2 x 12, span = 14' CsubL = 0.94
3.125 x 12 GLB, span = 16' CsubL = 0.75
3.125 x 16.5 GLB, span = 16' CsubL = 0.56
The volume factor for both GLB examples was 1.00 so the CsubL governed.
RE: CsubL value for headers
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.