AISC 360 and seismic design cat D

[MachelJacobs4]

I believe a building or non-building structure can be designed according to the provisions in AISC 260 in seismic design category D if the R value is less than 2.5? I can only find references that indicate Seismic Cat D-F require detailing per AISC 341. Please provide comment.

 

[structSU10]

ASCE 7-05 14.1.3 states structures in seismic design category D-F shall follow AISC 341.

AISC 341-05 Scope states that the provisions apply for an R > 3, and need not be applied if R <= 3 unless required by the applicable building code.

ASCE 7-05 table for determining R factor also has limitations on building height allowed for each system in each seismic category. This is true for both building and non-building structures.

 

[jdgengineer]

A couple of things to note...

ASCE 7 Chapter 14 in its entirety is not adopted by the IBC codes. See the Referenced Standards in Chapter 35. I'm not entirely sure why, and I think it makes it confusing, but it is not adopted.

Section 2205.2.2 of 2012 IBC states "Structural steel structures assigned to Seismic Design Category D, E, or F shall be designed and detailed in accordance with AISC 341, except as permitted in ASCE 7, Table 15.4-1"

Therefore, in Seismic Design Category D-F even if you use a lower R value you must detail according to AISC 341 (with exceptions as noted in Table 15.4-1).

 

[MachelJacobs4]

Well I meant AISC 360 not 20 - Oops. We are required to use the newest codes - IBC 2012, Asce 7-10, AISC 341-10 and AISC 360-10.

 

[MachelJacobs4]

jdgengineer - Thank you. That is table/reference I was looking for.