Braced frame and shear wall lateral load resisting system
Braced frame and shear wall lateral load resisting system
(OP)
I am designing 6 story building using ram structural system. My building is rectangular and satisfies the rigid diaphragm criteria. I am using braced frame and shear wall for lateral load resistance. 90% of the system is braced frame and I used service elevator shaft to the very right of the building as a shear wall. Has any body has the experience of mixing these two systems and if so on what shall I be concerned? Ram program seems distributing the shear load reasonably.






RE: Braced frame and shear wall lateral load resisting system
As it is at one end this will result in a twisting motion in the diaphragm.
Is this in a seismic zone?
RE: Braced frame and shear wall lateral load resisting system
Thanks
RE: Braced frame and shear wall lateral load resisting system
Because your stiff element is on one side of your building, the other end of your structure will sway relative to the lift shaft, and a torsional moment will be introduced.
Try to make your lateral system as symmetric as possible. Try and get a shear wall on the side of your building opposite to the lift shaft.
RE: Braced frame and shear wall lateral load resisting system
Thanks All
RE: Braced frame and shear wall lateral load resisting system
You did not mention the Seismic Design Category (SDC). If you happen to be in SDC "C" or lower, try using an OCBF. You will be spending a lot of money on meeting the detailing and brace configuration in an SCBF.
RE: Braced frame and shear wall lateral load resisting system
around your elevator shaft, you can't even take advantage of the R=6 for the steel braced frame, as I understand it.
If you are in SDC "B", I would recommend using a "steel system not specifically detailed for seismic" and take an R of 3. The higher design forces will require larger members, but usually the simpler connections will make the frame more economical.
RE: Braced frame and shear wall lateral load resisting system
RE: Braced frame and shear wall lateral load resisting system
The problem of using steel system not specifically detailed for seismic in my case is having a very heavy uplift load on certain areas around 500kips. It is such a large load to be taken by anchor bolts at these column location. I am using SCBF and I am not using shear wall in conjunction with BF. It helped a lot in reducing the uplift load and the connection size was not that bad at all eventhough it was not same as the ordinary connection. Because here you desing for the member capacity instead of for the actual load.
Thanks all
RE: Braced frame and shear wall lateral load resisting system
Good Luck!
RE: Braced frame and shear wall lateral load resisting system
Your center of Rigidity should be close to center of mass. When you say braced frame ? what is bracing these frames ??