Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Anchor Rod Repair

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Eric,

What are the loads on the bolts, what is the bolt diameter and what is
the bolt material? If the loads are not too large maybe you can just
install some beveled shim plate so that the nuts will have full bearing
when tightened. If the bolts are 3/4" diameter and are made of A36
material then the contractor can probably "whack" them straight. The A36
material should be ductile enough to deform without breaking.  Of course
if the threads are deformed during the straightening operation, there
may be some difficulty installing the nuts. 

If the bolts (oops, I mean "anchor rods") are tilted such that they
won't fit through the holes in the baseplate, enlarge the holes (as you
suggested) and install a new plate washer (maybe 4"x1/2"x4" with
standard size holes) on each bolt to cover the enlarged holes - provided
you have enough bolt projection. 

In any case, if you are concerned about the 20 degree tilt in the bolts
and how that will affect the pullout capacity of the bolts I would not
be concerned especially if the bolts are installed in an area where
there is lots of top steel and tendons. The top tendons and rebar will
help to restrain the bolts as they try to straighten when loaded.

Straightening the bolt projections to facilitate baseplate installation
will not fix the tendency of tilted portion of the bolt (in the
concrete) to want to straighten when tensioned.


Cliff Schwinger

> -----Original Message-----
> From: Eric Ober [mailto:eric(--nospam--at)cagley.com]
> Sent: Wednesday, July 10, 2002 4:47 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Anchor Rod Repair
> 
> I currently have a job where the anchor rods for steel column bases
have
> been installed incorrectly (shocker).  Templates were used so that
> overall layout is correct but the rods have tilted during concrete
> placement.  I am wondering about potential repair options.
> 
> I realize I could abandon the cast-in-place rods if needed and drill
in
> new ones.  However the columns are founded on a post-tensioned slab
and
> beam system.  So drilling is my least desirable option.
> 
> I've read where the rods can be "hickeyed" back to vertical.  I'm not
> sure what are the limits as to how much movement can be tolerated
> without damage to the rods or concrete bond.  I've also considered
just
> slotting the base plate and dealing with them in that manner when the
> tilt is not too bad.  However the contractor has indicated that some
may
> approach 20 degrees tilt from vertical.
> 
> Any suggestions are welcomed.  Thanks.
> 
> Eric Ober


******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********