ASCE 7-05 table 12.8-2
ASCE 7-05 table 12.8-2
(OP)
I design mostly small steel framed buildings (less than three stories in height) nothing glamorous. When checking seismic loads I typically use a R=3 systems to avoid the seismic requirements (mostly the connection forces). Recently I designed a 3 story office building that required the use of an eccentric braced frame system. Again, to avoid the seismic requirements I used a R=3 system. My question is in relation to table 12.8-2 of ASCE 7-05. As I read this table, I could use a Ct = 0.03 for this system as there is nothing in the table that says the Eccentrically braced steel frames must be in compliance with the seismic provisions. Is this interpretation correct?






RE: ASCE 7-05 table 12.8-2
RE: ASCE 7-05 table 12.8-2
RE: ASCE 7-05 table 12.8-2
RE: ASCE 7-05 table 12.8-2
14.1.2 Seismic Design Categories B and C. Steel structures assigned
to Seismic Design Category B or C shall be of any construction
permitted by the reference documents in Section 14.1.1.
An R factor as set forth in Table 12.2-1 is permitted where the
structure is designed and detailed in accordance with the requirements
of AISC 341 for structural steel buildings and AISI Lateral
for light-framed cold-formed steel construction. Systems not detailed
in accordance with AISC 341 or AISI Lateral shall use the
R factor designated for “Structural steel systems not specifically
detailed for seismic resistance” in Table 12.2-1.
If you satisfy this paragraph then R3 could be used and yes, I would agree with your interpretation of Table 12.8-2
RE: ASCE 7-05 table 12.8-2
Thanks, the SDC for this particular structure is B with a height of approx 44 feet. So I am justified in using a system with R=3.
RE: ASCE 7-05 table 12.8-2