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

Re: Anchor Bolts Revisited

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Bent bar anchor bolts seem to be still allowed in masonry by the 97 UBC with
appropriate minimum bend diameters and hook extensions in 2106.2.14. You
don't often see these specified in details and at the job site but they
should be called out. Similarly in concrete Table 19-D calls for a standard
head or "equal deformity". The California Building Code's state amendments,
where applicable, limit J or L bolts in concrete to anchoring light frame
sills and don't allow such bolts for structural applications in masonry. The
CBC also limits the max dimension of headed bolts as a function of the wall
thickness in masonry.

The 2000 IBC has a new provision for added plates or washers are used with
headed anchors in concrete - the max effective perimeter is limited by the
thickness of the washer in 1913.5.2.8.

The pullout strength of L bolts in the 2000 IBC  is, in part, now recognized
as a function of the length of the extension of the L in both concrete and
masonry.

So headed bolts are preferable for pullout. But if you still plan on using J
or L bolts, specify and enforce the necessary bend diameters and extensions.

Is this the current situation?

Fred Turner, Staff Structural Engineer, California Seismic Safety
Commission, 1755 Creekside Oaks Drive Suite 100, Sacramento, CA 95833
916-263-0582 Work Phone, 916-263-0594 Fax fturner(--nospam--at)quiknet.com

----- Original Message -----
From: "Scott E Maxwell" <smaxwell(--nospam--at)engin.umich.edu>
To: "Seaint" <seaint(--nospam--at)seaint.org>
Sent: Friday, August 25, 2000 2:25 PM
Subject: Re: Anchor Bolts Revisited


> I was taught NOT to use "j" anchor bolts.  The reasoning that I was taught
> was the concrete in the just above the hook could start to crush as a
> tensile load is applied.  As this happens, the hooked portion will start
> to straighten out.  The end result is that the "j" anchor bolts (er,
> excuse me...that would be "rod" now a days) would pull out of the hole as
> someone else stated.
>
> Scott Maxwell, PE, SE
>
>
> On Fri, 25 Aug 2000, PEC - Lake City wrote:
>
> > On the list, we recently discussed the pros and cons of using anchor
bolts
> > with nuts versus anchor bolts with plate washers, etc.  What about
> > "j-anchors"?
> >
> > I am reviewing some shop drawings for some mast arm structures.  These
> > typically have drilled shaft foundations and historically the
fabricators
> > have used very long anchor bolts (7'-0" long anchor bolts are not
uncommon)
> > with a "J-Hook" at the bottom.
> >
> > How well do the hooked anchor bolts perform compared to the straight
anchor
> > bolts with nuts for tension loading?
> >
> > Perhaps one of the fabricators can answer this one:  Are the long anchor
> > bolts provided for convenience (since the fabricator typically does not
> > design the foundation and therefore, does not know what kind of
reinforcing,
> > etc. is provided for the load transfer)?
> >
> > David Finley, P.E.
> >
> >
> >
> >
> > ******* ****** ******* ******** ******* ******* ******* ***
> > *   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) to the list, send email to
> > *   admin(--nospam--at)seaint.org and in the body of the message type
> > *   "join seaint" (no quotes). To Unsubscribe, send email
> > *   to admin(--nospam--at)seaint.org and in the body of the message
> > *   type "leave seaint" (no quotes). For questions, send
> > *   email 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
> > ******* ****** ****** ****** ******* ****** ****** ********
> >
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> *   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) to the list, send email to
> *   admin(--nospam--at)seaint.org and in the body of the message type
> *   "join seaint" (no quotes). To Unsubscribe, send email
> *   to admin(--nospam--at)seaint.org and in the body of the message
> *   type "leave seaint" (no quotes). For questions, send
> *   email 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
> ******* ****** ****** ****** ******* ****** ****** ********


******* ****** ******* ******** ******* ******* ******* *** 
*   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) to the list, send email to 
*   admin(--nospam--at)seaint.org and in the body of the message type 
*   "join seaint" (no quotes). To Unsubscribe, send email 
*   to admin(--nospam--at)seaint.org and in the body of the message 
*   type "leave seaint" (no quotes). For questions, send 
*   email 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 
******* ****** ****** ****** ******* ****** ****** ********