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RE: phi in both sides of formula 14-1

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I have been quite intrigued by this on-going saga.

Whilst I do not have at hand the specific formula 14-1, I am familiar with
the concept.

Here "down under" we have similar expressions in the local standards/codes.

I believe this is a mathematically correct algebraic expression.

As Paul observed - taking phi from the LHS of the expression and placing on
the RHS we get a division.  As noted phi/phi becomes "1" and hence the
expression becomes Pnw = 1 x (whatever constitutes the expression for Pnw
this side) hence mathematically consistent

Or am I missing something ??

Roy Harrison
 
Roy Harrison & Associates
Consulting Structural Engineers
Adelaide - South Australia
 
mailto:ro35984(--nospam--at)bigpond.net.au
http://users.senet.com.au/~tectonic/

	-----Original Message-----
	

 


-----Original Message-----
From: Gary Hodgson & Associates [mailto:ghodgson(--nospam--at)bellnet.ca] 
Sent: Friday, 31 March 2006 11:29 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: phi in both sides of formula 14-1


I have never liked that usage but since it does't
affect me (Canada) I never had cause to comment.
Here (where Wyoming looks balmy, David),the left hand
side of our equations uses M(Sub)r, V(Sub)r, etc, 
indicating the resistance of the member.  I much prefer
ours but it really is a matter of what you are used to.
I could see someone like Eugenio making the assumption
that it is part of an algebraic equation, as that was
the same  assumption I made when I first saw a US code
with that content.
Gary


On 30 Mar 2006 at 13:43, Paul Feather wrote:

> Yes Dave, I will admit to the same off-beat comedic reaction.
> 
> On the other hand, to answer the man's question:
> 
> Eugenio,
> 
> The design expression is not straight algebra the way you are thinking 
> of it.  The phiPnw is the name of the variable you are trying to find, if
this makes sense.  The axial load strength, Pnw,  would be 14-1 without
"phi", the design axial load strength is "phi" times the axial load
strength.  Since phi is in the right side of the equation, the nomenclature
is phi-Pnw on the left so you know phi has been applied.  It would not
cancel out algebraically.
>  
> Paul Feather PE, SE
> www.SE-Solutions.net
> pfeather(--nospam--at)SE-Solutions.net
>   ----- Original Message ----- 
>   From: David Maynard 
>   To: seaint(--nospam--at)seaint.org 
>   Sent: Thursday, March 30, 2006 12:08 PM
>   Subject: RE: phi in both sides of formula 14-1
> 
> 
>   Eugenio wrote:
> 
>   "I am confused with the formula (14-1) "Design axial load strength"
which sowns a factor "phi" at the two sides of the formula.     In the 2001
California Building Code.
> 
>   My recollection in algebra says that a value goes to the other side 
> of the formula with the oppossite sign. If I follow the rule, "phi" 
> multiplying goes dividing, means phi/phi=1.
> 
>   Why in such Chapter 19, DIVII - 1914.5.1 even it gives a value of 
> 0.70 to phi?.
> 
>    
> 
>   I will appreciate your comments, specially because I am an 
> architect."
> 
>    
> 
>   In response:
> 
>   I think the last statement just about sums up the root of the 
> problem right there.
> 
>    
> 
>   *laugh*  Sorry, I couldn't resist.  *laugh*  Just havin' some fun.  
> I'm in a goofy kinda mood today.
> 
>    
> 
>   But come on. how many Engineers out there read that statement and 
> thought the exact same thing.  I know you're out there.  You know who 
> you are!!!
> 
>    
> 
>   Comedy by:
> 
>   Dave Maynard, PE
> 
>   Gillette, Wyoming
> 
>    
> 
>   P.S. The wind's blowing like crazy today.  I'm starting to get cabin 
> fever.
> 
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