Shear wall over a wood beam

[perland]

Hello,

When load combinations with seismic load effects and over strength factors are used for shear wall over a beam, how do I design the beam? Do I put the tension or compression on a beam one at a time for each load case, or I put two loads since compression on one side of the shear wall means tension on the other side. For example if my beam is 10' long and the shear wall 4', do I design the beam three times with the load at 3', or I put equal and opposite loads at 3' and 7' feet.

Thank You,

Victor.

 

[jdgengineer]

You would put both loads on at the same time. They may not be equal and opposite due to vertical seismic load that should be included as well.

Something that is often not checked in these situations but may very well govern is drift of the shearwall taking into account the deflection of the beam.

 

[KootK]

Yeah, both at once. Dealing with load cases is tedious enough without inventing new ones of your own. Further to JD's comment regarding drift, folks often consider the impact that beam deformation has on the stiffness of the wall and therefore the amount of load that may be drawn to the wall. It's a little simpler, of course, if you're in flexible diaphragm territory.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[perland]

Thank you for your responses.
Victor.

 

[mike20793]

Agreed with Koot and jdg. I find that detailing the diaphragm to transfer the shear to another shear wall for the level below much more tedious than the beam design. It can get down right nasty and I avoid it at all costs, even if I need to do something unconventional to get the boundary elements, drift, sheathing, etc to work. I would even go with the Simpson shear walls at a different location before trying it again. Of course, it doesn't get constructed at all as its intended.