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RE: Post-Installed Anchors and Cold Joints

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Jim,

The ERDC from Vicksburg has done the most research on post installed
anchors, but they don't publish much.  In the public domain, this whole area
is still in flux because the manufacturers can not agree on testing
protocol.

Research on cast in place anchors has been done by:
*	Texas Tech for the Texas DOT - Dr. Hasslewander, Dr. Klingner, and
Dr. Jirsa
*	TVA (for ACI 349 Appendix B)
*	University of Stuttgart - Dr. Eligehausen. Dr. Fuchs
*	University of Florida - Dr. Cook (author of PCA Strength Design of
Anchorage to Concrete)

Specifically to your problem, I don't see how the cold joint will make an
appreciable difference if the anchor is installed and the load is applied
normal to the plane of the cold joint.  The best thing to do is to install
the bolts, and tension the anchors to a load in excess of the applied load.
This is the practice in the petrochemical industry for many types of
anchors.  Reference ASCE Petrochemical Energy Committee, "ASCE Task
Committee on Anchor Bolt Design".  They recommend to design the bolts to be
tensioned to 1/3 of the minimum ultimate tensile strength.  I generally go
up to 1/2 of the minimum ultimate tensile strength.  The bolts are designed
so that the applied load does not exceed the applied tension force.  The
applied load should not exceed the clamping load. 

Regards,
Harold O. Sprague

> 	----- Original Message -----
> 	From: Andel James Contr AAC/WMO
> 	Sent: Wednesday, August 07, 2002 2:14 PM
> 	To: 'seaint(--nospam--at)seaint.org'
> 	Subject: Post-Installed Anchors and Cold Joints
> 	 
> 	We have a situation where we need to install several undercut
> anchors 30 inches deep into a 4,000 psi concrete base. This is based
> embedment into a monolithic base using the standard projected stress cone
> method for determining pullout strength.
> 	
> 	Our problem is that there is a designed cold joint 21 inches below
> the surface of the concrete. The cold joint was constructed using an epoxy
> bonding agent that meets ASTM C-881 and has an ASTM C-882 slant shear
> bonding strength of 2,000 psi.
> 	
> 	Is anyone aware of any research reports or guidance pertaining to
> how this type of cold joint would (or would not) affect the holding
> strength of the anchors?
> 	
> 	Thanks
> 	JimA 
> 

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