DavitBek
Structural
- Aug 5, 2019
- 4
Hi All
I'm finalizing the design of a six story mixed use structure(resident/commerc.), two stories concrete (one above ground, one below), and four stories of wood sitting on top of the concrete podium. The structure is located in downtown Los Angeles.
The front of the building, which is its main architectural feature, consists of a series of mostly non-stacking, tall, narrow windows (w=2'-8"; h=7'-8") across the length of the four wooden stories.
There's more than enough wall in between the windows, where double sided shear walls are not needed, not even on the lowest floor.
However, for some reason, the architectural group was extremely concerned and insistent that the design will not pass city planning. that non-stacking shear walls are not accepted for structures greater than two stories in Los Angeles.
Having been designing structures of this type for five years here in Los Angeles, I had not heard of such a limitation. Neither had any of my coworkers or the owner of the company. With the architectural group not being satisfied with our assurances that such a thing does not exist, the owner of my company met with the head of planning/plancheck here in Los Angeles, and the person told him that while they are allowed, he will require a multiplier factor of 4 on the non-stacking shear wall holdowns (roughly half of the holdowns come down on headers, with the other half sitting on walls but then landing on a header one floor below). This is in the place of the 2.5 omega factor that is typically applied to those holdowns on headers/beams.
While even the X4 multiplier factor is still fine (and insignificant) given that the headers are a mere 2'-8", I wanted to know if such a thing as a 4X multiplier factor exists anywhere in the code, as I have never heard of such a thing either.
Furthermore, I wanted to know where this non-stacking shear wall idea could be coming from, given that this is supposedly a highly reputed architectural company in Los Angeles (though in my exchanges with them, their structural knowledge has been severely and shockingly lacking, even when it pertains to the most basic concepts)
I'm finalizing the design of a six story mixed use structure(resident/commerc.), two stories concrete (one above ground, one below), and four stories of wood sitting on top of the concrete podium. The structure is located in downtown Los Angeles.
The front of the building, which is its main architectural feature, consists of a series of mostly non-stacking, tall, narrow windows (w=2'-8"; h=7'-8") across the length of the four wooden stories.
There's more than enough wall in between the windows, where double sided shear walls are not needed, not even on the lowest floor.
However, for some reason, the architectural group was extremely concerned and insistent that the design will not pass city planning. that non-stacking shear walls are not accepted for structures greater than two stories in Los Angeles.
Having been designing structures of this type for five years here in Los Angeles, I had not heard of such a limitation. Neither had any of my coworkers or the owner of the company. With the architectural group not being satisfied with our assurances that such a thing does not exist, the owner of my company met with the head of planning/plancheck here in Los Angeles, and the person told him that while they are allowed, he will require a multiplier factor of 4 on the non-stacking shear wall holdowns (roughly half of the holdowns come down on headers, with the other half sitting on walls but then landing on a header one floor below). This is in the place of the 2.5 omega factor that is typically applied to those holdowns on headers/beams.
While even the X4 multiplier factor is still fine (and insignificant) given that the headers are a mere 2'-8", I wanted to know if such a thing as a 4X multiplier factor exists anywhere in the code, as I have never heard of such a thing either.
Furthermore, I wanted to know where this non-stacking shear wall idea could be coming from, given that this is supposedly a highly reputed architectural company in Los Angeles (though in my exchanges with them, their structural knowledge has been severely and shockingly lacking, even when it pertains to the most basic concepts)
