Steel Posts Embedded in Concrete & Block wall

by Tom Fagan
(Laguna Beach, CA)

Question:

I like your website but I still have 3 questions:
1. How do you cap a block retaining wall with ½” thick steel to provide the substrate to anchor a glass wall/railing shoe moulding?
2. Can you anchor a 4x4 steel post in a block wall by going down through the cells 4’ and back filling with cement?
3. Can you anchor a 4x4 steel post in a sonotube or is it always with a base plate with anchor bolts in the sonotube or footing and a post with base plate bolted to it?

Answer:
Hi Tom, thanks for visiting all-concrete-cement.com

Answer to question 1: You can make the top one or two cells of your wall a bond beam. This would mean you will have to grout solid the bond beam. In order to embed the ½” thick plate on your wall, you need to shoot weld studs or Nelson Studs on one side of the steel plate. You can use ½” diameter Nelson Studs 3 to 4 inches long, spaced at 24 to 32 inches on center.

Weldable rebars in lieu of Nelson Studs will work as well but they need to be bent one end to look like a J. Assuming that your wall is outside exposing to weather, the steel plate will need to be galvanized. Immediately after grouting the bond beam to the very top (and while the grout is still wet) lower the steel plate on top of the wall with the side where the Nelson Studs are welded facing the grout such that the Nelson Studs are buried into the wet grout. Tab on the steel plate with a hammer to make sure there is no void left between the Nelson Studs and grouting. Once the grout is dried, the steel plate will become the cap of the wall.

Answer to question 2: The answer is yes you can embed the TS4x4 steel post inside the block cell and then grout it. If these TS4x4 posts are to resist of lateral loads, it is common practice to weld Neson Studs to the side of the tube steel before inserting them into the block wall. This will strengthen the tube steel laterally. The challenge with this method is you only have limited time to precisely placed and straighten and braced the post before concrete start setting. It is especially challenging if you have a lot of posts to be installed after placing grout.

Answer to question 3: You can fill the sonotube with concrete before inserting the steel post into concrete. Welding Nelson Studs to the side of the steel post, the same way in question 2 above is a great way to stiffen the steel post. The base plate mentioned is a great way to place the steel post at precise location prior to concrete. The base plate also helps spread the load instead of having it concentrate at a single point.

Hope this helps
Good luck