Anchor Bolts at Mono Pour

by John
(DE)

Question

HOW ARE THE ANCHOR BOLTS PUT IN A MONO POUR


Answer
Hi John, that's a great question. You probably talking about anchor bolts at the interior footings where there can be hundreds if not thousands to install. That will be a huge challenge against time in trying to finish the concrete and install the AB simultaneously. Here are two options that I can think of:

Option 1
Instead of J bolts, go with epoxy bolts or expansion bolts. Most anchor bolts required at building interiors for shear, not uplift. Both threaded rods for epoxy anchors as well as expansion anchors have great shear value. This should be first option to explore.

While contemplating options to take, send the engineer of record an RFI(request for information) asking replacement of anchor bolts as mentioned.

If you are doing this as a sub, provide cost break down for the 3 types of anchors. Since most decision is based on cost, make your preferred method the most cost effective.

I personally prefer this route because it's less risky. If the building layout is not accurate, you have no other choice but to drill and epoxy or expansion anchors. Why not make this the primary option?

Option 2
If the EOR (engineer of record) is not very good or inexperience he will not allow option 1. In that case pre-install the J bolts on the bottom plate pressure treated lumber or metal studs for metal stud framing. This will require the nut and washers install too. Make sure the spacings match what the plans call for. With steel stakes, that means a lot of them install these bottom plates where they need to be. Lateral braces will be required to prevent movements of these anchors during pour. This will require a lot of preparation prior to pour. Again double and triple check layout, there is only one chance to get this right and make sure the concrete finishers don't touch or lean on them.

Hope this help
Tonga