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RE: Rebar lap lengths

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I don't know Enercalc.  Based on ACI 318-02 12.2.3 & R12.2, 1.5 < or = {(c+Ktr)/db} < or = 2.5: ld = 19.72" = 20" when using 2.5 & ld = 32.86" = 33" when using 1.5.  You are using 2.5.  And 2.0 may be used by Enercalc.  (EQ. 12-1) is under Section 12.2.3 & the actual {(c+Ktr)/db} shall be used per R12.2 .
-----Original Message-----
From: Jason Christensen [mailto:jason.christensen(--nospam--at)]
Sent: Thursday, September 29, 2005 11:47 AM
To: seaint(--nospam--at)
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.