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# Re[2]: Enercalc Reinforced Concrete Beam design

• To: seaoc(--nospam--at)seaoc.org, volnyeng(--nospam--at)COINET.COM
• Subject: Re[2]: Enercalc Reinforced Concrete Beam design
• From: jerome.tan(--nospam--at)PAREURO.COM
• Date: Thu, 9 Jul 1998 18:44:40 +0000

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I, too, have never used enercalc. But, irregardless of the direction
of the load, the maximum positive moment or negative moment for a
fix-fix support with the load indicated is with the absolute value of
19.56 K-ft.

Following the premise that the load as indicated was downwards and the
resulting value is -19.56, then it would just indicate that the major
reinforcement would be at the top since this is in tension and the
bottom side is in compression. If, however, the load was upwards, then
the major reinforcements would be at the bottom since this is the side
in tension.

Following should be the capacities should the material parameters are
as indicated:

fc = 3 ksi      fy = 40 ksi     cover = 1.5"     Mu = 17.0 k-ft
fc = 3 ksi      fy = 60 ksi     cover = 1.5"     Mu = 24.6 k-ft
fc = 4 ksi      fy = 40 ksi     cover = 1.5"     Mu = 22.6 k-ft
fc = 4 ksi      fy = 60 ksi     cover = 1.5"     Mu = 32.8 k-ft

There's a 3.15% differential between your result and my first set of
parameters. Could be it be that enercalc is providing a certain percentage
below or above theoretical values(like say plus or minus 5%)? And if
your value falls within the limit, it says OK?

Jerome
Subject: RE: Enercalc Reinforced Concrete Beam design
Author:  MIME:volnyeng(--nospam--at)COINET.COM at INTERNET
Date:    7/8/98 6:57 PM

>I have never used Enercalc, however, it would seem that the loading may be
>upwards instead of downwards? Usually down loads are input with a negative
>sign.  Hope this is the simple answer.
>
>
>-----Original Message-----
>From:	John Armijo [SMTP:421jarmi(--nospam--at)pwcsd.nosc.mil]
>Sent:	July 07, 1998 10:56 AM
>To:	seaoc(--nospam--at)seaoc.org
>Subject:	Enercalc Reinforced Concrete Beam design
>
>I am  designing a reinforced concrete lintel over a 12'-0" masonry
>opening. I have input 2 # 5 Top and Bottom of a 8" wide by 12" deep
>beam. End conditions are Fixed-Fixed, Seismic Zone 4, 150PCF concrete
>weight, uniform dead load of 1.064 KLF, and #3 ties. All other input values
>are the defaults.
>
>I have two questions:
>
>1. Which version of the ACI Code is being used?
>
>2. For the input above I get Maximum Moment, Mu=  -19.56 K-ft and
>Allowable Moment, Mn/phi= 16.48 K-ft and a note saying, "Beam Design
>OK". Granted a positive number is larger than a negative number, but my
>concern is that the absolute value, | -19.56 | is greater than the absolute
>value of | 16.48 | and that the beam design is NOT OK.
>
>Can anyone shed some light on this?
>
It appears to me that :

1. There may be an inadvertant crossover in the language used in defining
the allowable moment versus the Maximum ultimate moment. Terminology is used
from both WS and USD in defining the output.

2. I would check it by hand using something as archaic as "moment
distribution"..... A simple check would be a uniform load...

3. I'd be tempted to assume that the max moment would be at a support....but
we all know that assumptions can be the "mothers" of many bad things!!

Norb Volny ,PE
Bend ,Or.

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