ACI 318 Appendix D per 06 IBC 1912.1

[STR04]

The 2006 IBC, section 1912.1 states ‘The strength design of anchors that are not within the scope of Appendix D of ACI 318, and as amended above, shall be in accordance with an approved procedure.’

First question: What defines an approved procedure? Is AISC's Design Guide 7 for Industrial Building, Section 9 an approved procedure?

I’m only Designing column anchor bolts in a reinforced pier and using Appendix D is a difficult task as we all know.

TIA

 

[Bagman2524]

That sounds like a good question to ask ICC. They have a pretty good technical staff that handles questions. iccsafe.org

 

[JedClampett]

I can't see why any anchor bolts wouldn't be in accordance with Appendix D.
I think they're trying to include adhesive type anchors, not covered by appendix D. I suspect you're getting hung up by the term "strength design" which is in there just to show that's the only design available for adhesive anchors. The "approved procedure" includes such tools as ICBO Reports.

 

[JAE]

Appendix D doesn't just deal with adhesive anchors but all embedded cast-in or expansion type anchors as well.

The approved procedure in the IBC suggests that the building official must aggree that it is approved. There is also Table 1911.2 in the 2006 IBC that doesn't involve the Appendix D methodology and is "acceptable" in that it is in the code iteself.

 

[OldPaperMaker]

JAE,
Section 1911.1 says that ASD, which is shown in Table 1911.2, can't be use where "load combinations include earthquake loads or effects and the design strength of anchors shall be determines by using Section 1912" which is the dreaded ACI 318-05 Appendix D.

My question is: If the load combinations included seismic loads, but, the wind loads are greater and govern the design, can we use the shear and tension values in Table 1911.2 for anchor bolts design?

I am thinking about this for Light Framed construction, i.e., wood framed,panel sheathing shearwalls.

 

[JAE]

Nope - you have to design to ALL the load combinations.

Wind may "control" the design, but the design is still required to meet the seismic loads as well. So if you use an anchor that is strong enough for wind loads per the ASD table, but cannot meet the load combination requirements for seismic, you've NOT met the code.

 

[JAE]

OldPaperMaker - Hey I forgot to point out that you comment on seismic not being applicable to the ASD table was helpful. I didn't see that.

 

[OldPaperMaker]

JAE,

Thanks for your thoughts on the subject.

I will have to think about the notion of using ASD load cases for the shearwalls & diaphragms and then when one gets to the anchor bolt design switching to Strength design for the seismic (not wind).

Does that mean that you would advocate doing both ASD & Strength load cases just so you would have the loads to do Strength design of anchor bolts?

If I am off base I better do less talking and more listening.

 

[arnoldistuno]

Great stuff- I'm looking at Table 1911.2 in IBC 2006 and noticed the values where extremely conservative. 4000 psi concrete, with a 1" dia bolt and 7" embed is only good for 3650 lb in tension. I quickly compared that to a hilti RE-500 epoxy anchor (which intuitively should be significantly less, right?) has a value of 8440 lb with 4.5" embed. Is this just a table for the lazy/time restrained engineer who doesn't care about costs?

What are your thoughts? The HILTI value is ASD like the table.

 

[msucog]

there are many things in IBC that have bigger safety factors applied. in my opinion (and i think this is the intent), ibc should be construed as "the minimums" based on a straight forward approach (i.e. without additional analysis). keep in mind that they can't govern every single scenario in every place in the country...but they're a good place to start. most everything in ibc can be exceeded using engineering judgement and analysis...but you (as the designer) must be willing to step up and accept that responsible/liability.