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I have been trying to determine the response coefficients for seismic analysis of Non building structures in ASCE 7-10 and found that the value of R, the response coefficient, is larger in case steel connections are detailed using AISC-341 than AISC-360, this would imply a larger design load in case of AISC 341 than AISC 360.

So basically,

AISC 341 -> Large seismic design load
AISC 360 -> Smaller seismic design load

Does that imply AISC 341 design results in a more conservative steel connection than AISC 360 or is there a difference in steel design philosophy?

Wasabi
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Stephen Jacob
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2 Answers2

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The R-factor reduces seismic design force from the linear-elastic demand. Thus, the larger the R-factor, the lower the seismic design force.

Essentially, we're approximating inelastic seismic design by accounting for the ductility of the structural system. Connections designed per AISC-360 (which does not specifically address seismic design) can be expected to be less ductile than those designed per AISC-341.

So.

AISC-341 = more ductile = higher R = lower seismic design force

AISC-360 = less ductile = lower R = higher seismic design force

CableStay
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I think that it should be like this:

AISC-341 = more ductile = lower R = higher seismic design force

AISC-360 = less ductile = higher R = lower seismic design force

OnePowers
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