Existing Cantilevered Column System for a Two Story?

[chamokinawan]

I am doing a remodel for a two-story commercial building, shortening 2 shearwalls. On the second floor, there are two obvious wood shear walls, but they are on opposite ends of the building about 106' apart. There are 6" dia. HSS columns about 24'± on center in between the shear walls. Right below the HSS are W 12x Columns on the first floor. I'm having a hard time believing the diaphragm is spanning 106' while only from shear wall to shearwall, it's only 52' deep. I want to assume the HSS are cantilevered columns. Has anyone done a 2-story cantilevered column system with splices between floors?

Building was built in the late 80's. We're in Southern California and seismic governs, SDC=D.

 

[KootK]

Your diaphragm aspect ratio is only about two. It should be able to span the entire length of the building without too much difficulty.

While could use a cantilevered column system in many situations, I have a very hard time seeing it work with 6" columns at 24' o/c in a high seismic zone like California. I expect that a back of the envelope calc on the column flexural capacity and drif required would eliminate this as a viable option pretty quickly.

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.

 

[chamokinawan]

KootK: Thanks. Just wanted a second opinion. Thank you.