Seismic detailing of existing buildings
Seismic detailing of existing buildings
(OP)
Our firm has been awarded a new hospital addition in a high seismic area. Governing code is IBC 2009. Site Class is D, spectral accelerations are high, so the SDC is D and by a mile. The structural narrative of the RFP lays this out and I have verified. However, the structural narrative of the RFP indicates use of R=3 steel moment frames per provisions of the International Existing Building Code. I am not aware of such provisions and have been unable to find them in my research. So:
1) Where are these provisions?
2) What are the ethics involved here? In such a high-risk area, should I even consider R=3 if the IEBC does indeed allow it? (The existing building is old and probably is detailed equivalent to R<3. The addition will be independent.)
Thanks in advance for your help.
1) Where are these provisions?
2) What are the ethics involved here? In such a high-risk area, should I even consider R=3 if the IEBC does indeed allow it? (The existing building is old and probably is detailed equivalent to R<3. The addition will be independent.)
Thanks in advance for your help.






RE: Seismic detailing of existing buildings
However, after talking with your superiors, if they agree, it would be prudent to write a letter to the hospital administrators informing them of your concern.
Mike McCann
MMC Engineering
RE: Seismic detailing of existing buildings
RE: Seismic detailing of existing buildings
RE: Seismic detailing of existing buildings
The question is related to the NEW construction (the addition which is not attached to existing). The structural narrative indicated R=3 system was possible per provisions of the IEBC. Everything I am reading says that the new work must conform to the current building code, which would be IBC 2009, which would require R>3.
My question is: where in the IEBC does it allow for an independent addition to be R=3, even though the SDC is D?
RE: Seismic detailing of existing buildings
A system were R=3 most likely will not result in a very economical design. In addition, I am not even sure what system would qualify for use in this scenario.