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# RE: Rebar lap lengths

• To: <seaint(--nospam--at)seaint.org>
• Subject: RE: Rebar lap lengths
• From: "Martin Li" <mli(--nospam--at)tb-engr.com>
• Date: Thu, 29 Sep 2005 16:41:36 -0500

 Jason,   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 .   Martin   -----Original Message-----From: Jason Christensen [mailto:jason.christensen(--nospam--at)es2eng.com]Sent: Thursday, September 29, 2005 11:47 AMTo: seaint(--nospam--at)seaint.orgSubject: 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