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# RE: Rebar lap lengths

• To: <seaint(--nospam--at)seaint.org>
• Subject: RE: Rebar lap lengths
• From: "Jason Christensen" <jason.christensen(--nospam--at)es2eng.com>
• Date: Thu, 29 Sep 2005 11:36:14 -0600

No, I am only using equation 12-1, this is the equation that enercalc told me they are using. In comparing my hand calcs and their computer results, I am getting different results.

Jason

-----Original Message-----
From: Garner, Robert [mailto:rgarner(--nospam--at)moffattnichol.com]
Sent: Thursday, September 29, 2005 11:18 AM
To:
seaint(--nospam--at)seaint.org
Subject: RE: Rebar lap lengths

Jason,

If I understand your question, ACI gives you a two tier approach, using either 12.2.2 or 12.2.3, which may have different results.  See the commentary.  Is that what you are inquiring about?

Bob Garner, S.E.

From: Jason Christensen [mailto:jason.christensen(--nospam--at)es2eng.com]
Sent: Thursday, September 29, 2005 9:47 AM
To: seaint(--nospam--at)seaint.org
Subject: Rebar lap lengths

Question to all,

I know this must sound like a stupid question, but here it goes.

I am trying to write a MathCAD sheet for rebar lap lengths.  Typically I have used Enercalc to get these values.  While writing the MathCAD sheet I ran the equation in ACI318-02 (eq. 12-1) by hand for a #6 bar, fy=60000psi, f’c=3000psi, bottom bars, uncoated bars and normal weight concrete.  I also used   (c + Ktr)/db as 2.5 (max by code).  I ran this by hand and on the MathCAD sheet, and received 19.72 inches (class A splice), this caused me concern because Enercalc gives 25 inches.  Just to be safe I looked in the 2002 CRSI Design hand book and checked their tables, for this case I pulled 25 inches of lap, however, these tables are based on the ACI318-99 code.

Am I missing a step, or is there some factors that are elsewhere in the code?  Any help would be appreciated.

Jason

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