Concrete bolt questions

[streetglider]

How difficult it is to remove concrete bolt anchors? Can I reuse the same holes with new bolts if I do? Would I be better off drilling new holes about an inch away and filling in the old ones with some sort of patch? The old anchors have been unused for several years and there are only a few that still have a threaded area. This is what they look like now.

 

[Leaflessshadetree]

Drill them out. The wedge anchors are pretty easy to drill. If drilling new holes to put in new anchors I'd keep them a few inches away from any of the old ones.

 

[matt_i]

Need some more information, please. What is going back in the same area? Something critical/structural or just a general purpose item.

Its definitely easier to just drill a new hole but the potential is there to put a lot of stress in a small area and that's not good. Having a big piece pop out is a much bigger issue.

 

[59 wagon man]

the top part you show is just a wedge the threads are in the bottom wedge so they maybe fine

 

[mm08822]

If the anchor holes were originally drilled all the way through the concrete you may be able to drive the anchors deeper through the concrete until they exit. Try the one without the bolt first.

The anchor with the bolt present may still be re-usable. All depends what the purpose/condition is.

If you need to drill out the anchors, you may want to consider drilling out the remaining hole in the concrete one size larger to insure better hole uniformity for better anchor grip.

 

[rburke65]

What are you anchoring?

 

[wssix99]

The easy thing to do would be to ream out the holes and go up one size on the anchor.

If you put another one in to the side, it needs to be over 1X the depth of the hole away. The anchors work through a stress cone in the material:

You don't want the old hole (weak area) to penetrate the new cone.

 

[streetglider]

I am putting a gazebo up. It is on a small concrete pad by a boat dock so it can get a bit windy. I got it from the former owner who had it there but it hasn't been up in a few years so almost all of the bolts are missing. I think I have enough room to drill new holes two or three inches from the old ones. I was going to put them closer until I read this. I am going to try pounding them all the way through and using the old holes for new bolts. Thanks for the advice.

 

[matt_i]

For that fabric covered structure the loads are going to be small before the fabric simply tears apart. I would drill your holes nearby and use something like a Hilti KH-EZ anchor. Its essentially a hex head tapcon and doesn't put much stress into the concrete. I think Simpson has a competitive product but I've not used it.

You could probably get away with a drop-in anchor if you wanted to take the thing indoors during the winter.

 

[streetglider]

It will be taken down for the winter. Tomorrow it may actually be warm enough to go take a look and decide my best option from all the good advice I received.