Anchor bolt length?

[MBazan]

 Is is stated any where in code a set length for an anchor bolt or is there a norm used. We will be doing repairs to one of our tank floors and the repair will likely damage the existing anchor bolt. A new one will have to be replaced and tring to determine if there is a set depth for the ringwall.

Thanks for any info.....

[RDuwe]

Good question.

Like most 'Good Questions', the answer is a little nebulous.  The original anchors were poured into the concrete, with 'J' or 'L' shaped hooks on the end.  This means that original embedment length almost doesn't matter.  To put in a replacement anchor, the 'proper' method is to review the installation drawing and see what strength the original engineer specified in the anchor connections to the concrete.  NOBODY ever has that drawing.

I would duplicate the diameter of the existing anchors, using plated mild all-thread [typical existing poured concrete anchors are A-36 mild rod].  Then get a good grade of anchor epoxy -- Hilti or other name brand.  Check the literature, because in the back there will be a embedment length that will exceed the strength of the all-thread.  This will guarantee that your replacement anchor is as strong, and almost certainly stronger, than the existing anchors.  Do not torque up the nut until the epoxy is fully cured.  Time/temperature chart will be in the literature of good epoxy.

I've done this a lot on Structural Steel erection [mislocated anchors].  Pretty simple, pretty cheap, pretty fast.

[MBazan]

 Thanks for the response. The repair company was able to do repairs with out damaging the anchor bolt.