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RE:Post-Installed Anchors - again

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Actually, there is a new development on this subject. IBC 2009, Ch 1908.1.9 exempts anchors for nonstructural elements from the ductility requirements of ACI D.3.3.4 & 3.3.5. Someone finally realized that there was a triple penalty on these anchors. So this effectively reduces the safety factor from 1.3X2.5X1/0.75X1.4X1/0.65=9.33 to 1.3X1/0.75X1.4X1/0.65=3.73

Dmitri Wright, PE
Cascade Engineering, Inc.
245 SE 4th Ave, Suite B
Hillsboro, OR  97123-4033

From: Mark Johnson <markajohn(--nospam--at)>
Subject: Post-Installed Anchors - again
To: seaint(--nospam--at)

I hate to bring this up again, but ....

If I want to anchor some mechanical and electrical equipment to a concrete slab on grade for seismic (SDC E), I need to design the anchors for the design force times 1.3 (ASCE7 - bolts in concrete), 2.5 (ACI App.D for ductility) and 1/0.75 (per IBC; Ch. 14.2.2). In addition, there is special inspection.

Is that all still correct? Is there any new development I'm missing? (I hope, I hope)

Mark Johnson

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