Building Separation/ Seismic Gap
Building Separation/ Seismic Gap
(OP)
I am designing an addition to an existing building. Both structures are braced frame structures.
Do I need to design the gap between the structures per section 1613.6.7 of the IBC or is there a different requirement for the gap where additions are concerned or gaps in new structures?
Do I need to design the gap between the structures per section 1613.6.7 of the IBC or is there a different requirement for the gap where additions are concerned or gaps in new structures?






RE: Building Separation/ Seismic Gap
RE: Building Separation/ Seismic Gap
1613.6.7 per the original post is the right section per the 2009 code.
RE: Building Separation/ Seismic Gap
RE: Building Separation/ Seismic Gap
I have already around 7 inch of displacement (caused by torsional behavour) only for the newer building.
So imagine the total displacement if I sum inelastic displacement of both building using SRSS (canadian code)
The general practice of seismic engineering is just bad and fustrate me... don't know what to do !
RE: Building Separation/ Seismic Gap
How high are the structures and when was the first building designed?
Mike McCann
MMC Engineering
RE: Building Separation/ Seismic Gap
RE: Building Separation/ Seismic Gap
RE: Building Separation/ Seismic Gap
2" of deflection seems high for a standard braced frame. What is the length of the frame- and what type of frame is it? A picture might help
In order to reduce the separation, you may need to upsize the members.
RE: Building Separation/ Seismic Gap
Mike McCann
MMC Engineering
RE: Building Separation/ Seismic Gap
Using canadian limit for normal building as reference
36ft * 2.5% drift limit = 10.8 inch. max displacement allowed at upper level !
For a really stiff building, let's suppose 0.5% drift at each story
36ft * 0.5% drift limit = 2.2 inch. inelastic displacement at upper level !
So, if your value is between these, it's quite possible and normal!
If you want to control your displacement, you will need to increase the stiffness A LOT.
RE: Building Separation/ Seismic Gap
I have been able to reduce the gap a little by comparing deflections at the same elevations of the buildings.
Thanks,
RE: Building Separation/ Seismic Gap