# Seismic & Wind Forces by Alan Williams, 3rd Ed



## ARLORD (Sep 4, 2008)

For those of you who have this reference, on page 391, the third equation down the page Fc,min. It says that it is equation 8 from ASCE Section 12.4.3.2, but the equation has roe, the redundancy factor, and not the omega over strength factor as in ASCE 7-05. Is this an error. They are discussing collector elements, shouldn't the over strength factor be used here?


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## Bigwolf (Sep 5, 2008)

Yes--you are correct. :thumbs:

On a side note.....I've noticed A LOT of errors :brickwall: in all of William's books (Kaplan, ICC, etc), so keep a lookout. h34r:

I'm sure he rushed to get these texts out ASAP for the next exam cycle....but to have errors in formulas is just plain sloppy work.

Anyways--keep up the good fight! 10940623:


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## ARLORD (Sep 6, 2008)

OK thanks for the heads-up. However, I like the format of this book. It is easy to follow. I prefer more of a balance between the text and the calculations. I think the IBC Vol II &amp; III are heavy on the text side, but still has good information.


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## itsmemario (Dec 30, 2008)

For example 1-39 on page 95 and example 1-40 on page 97, should the final Fp value be multiplied by 1.4 as it states in section 1.29 (bottom of page 93)?


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## MOOK (Jan 2, 2009)

I think the equation for Fp used in Page 96 for Anchorage to Rigid Diaphrams is not the correct one. I think this equation is for mechanical and electrical components in Rigid Diaphrams.

IBC Vol. 1 used the equation Fp = 0.4 * SDs* I * Wp

Please let me know what u think.


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## ARLORD (Jan 3, 2009)

MOOK said:


> I think the equation for Fp used in Page 96 for Anchorage to Rigid Diaphrams is not the correct one. I think this equation is for mechanical and electrical components in Rigid Diaphrams.IBC Vol. 1 used the equation Fp = 0.4 * SDs* I * Wp
> 
> Please let me know what u think.


I agree, on page 135 of IBC Vol I, it uses 0.4SdsI. Section 12.11 is the correct section for diaphragms anchorage.

However, in IBC Vol I, page 133, calculation 1, it refers to Section 1620.1.7. I don't know what they are referring to, it is not ASCE &amp; or IBC.


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## ARLORD (Jan 3, 2009)

itsmemario said:


> For example 1-39 on page 95 and example 1-40 on page 97, should the final Fp value be multiplied by 1.4 as it states in section 1.29 (bottom of page 93)?



The 1.4 coefficient is per Section 12.11.2.2.2, for STEEL elements of the wall anchorage system only.


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## MOOK (Feb 7, 2009)

In page 302, Alan Williams used two different values for the Phi. Once he used it 0.75 and other time 0.85. I really do not understand why he did it like that. Can anyone explain?

In his seismic book by Kaplan, he solved the same example using Phi = o.85 and he did not use 0.75 !!!


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## whype (Feb 8, 2009)

MOOK said:


> In page 302, Alan Williams used two different values for the Phi. Once he used it 0.75 and other time 0.85. I really do not understand why he did it like that. Can anyone explain?
> In his seismic book by Kaplan, he solved the same example using Phi = o.85 and he did not use 0.75 !!!


In fact, 0.75 is the right value (resistance factor for shear, reinforced concrete members). 0.85 must be a typo.


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## McEngr (Feb 8, 2009)

whype said:


> In fact, 0.75 is the right value (resistance factor for shear, reinforced concrete members). 0.85 must be a typo.


0.85 was last used in ACI '99. '02 and beyond has been 0.75.

MOOK, ARLORD, and others: I have a pretty nice wall anchorage spreadsheet that I've modified from another spreadsheet. It was pretty nice for when I was working on rigid walls to spandrels.


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## MOOK (Feb 8, 2009)

Thanks Whype and McEngr

Actually, PhI is always = 0.75 for shear but I thought this is special case. Beam in High seismic area with subjected to Noraml force in addition to shear.

McEngr, do u like to share the spread sheet with us? I would be happy to.


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