Steel Manufacturing Blog: Keeping it Steel

Wedge Insert, Concrete Wedge Insert, The Basics

Posted on Mon, Feb 24, 2014 @ 05:55 PM


Concrete Wedge InsertWedge Inserts are also known as Relieving Angle Inserts, Shelf Angle Inserts, Malleable Iron Inserts and Lintel Inserts. Regardless of the name the photo to the right is the basic item.

The Wedge Insert is used to provide a system to anchor steel to concrete. There are some factors to be aware of if the building you are constructing calls for these anchors.

To view the catalog page showing sizes and Askew Head Bolts click here.

To view drawings showing the installation system click here.

Vertical Adjustment

The face of the Wedge Insert has a vertical slot. On the Regular Wedge Insert it is 2-1/2" long. On the Long Wedge Insert the vertical slot is 4" long. This is one of the most important features of the Wedge Insert. The vertical adjustment allows for corrections in placement or for variations in the concrete slab. It is what allows the erector to keep the Relieving Angle level. 

Askew Head Bolt


Wedge Surface Mates with Wedge on The Head of The Askew Bolt

The drawing to the right shows the angle in the head of the Askew Bolt. This mates with the sloped ledge inside the Wedge Insert. This important feature limits potential slippage as weight is applied.


Concrete Wedge Insert


Taped Face

While the concrete is being poured the heavy tape helps keep liquid concrete from entering the Wedge Insert cavity. Any cement in that cavity will inhibit the adjustment of the Askew Head Bolt. To keep the cavity empty it is also important to have the Wedge Insert firmly fastened to the plywood forms and make sure all nail/screw holes are covered.



Askew Bolts / Askew Head Bolts 

The Concrete Wedge Inserts available from stock use a 3/4" diameter Askew Head Bolt. Some companies indicate they also stock a Wedge Insert that uses a 5/8" diameter Askew Bolt however there are never any available. As far as we know the only new Wedge Inserts being made are for 3/4" bolts. 

Often renovation jobs on buildings from approximately 1980 and earlier will uncover Wedge Inserts that require 5/8" diameter Askew Bolts. For this reason The Steel Supply Company has the 5/8 diameter bolt in stock. To see the listing, click here.

Be careful with the dimensions of the Askew Bolt Head. The square head is designed to fit properly in the cavity of the Wedge Insert. Some non-compatible askew head bolts have smaller head dimensions which could affect performance. Below are the dimensions of the Askew Head Bolts in stock.

Askew Head Bolts

Made in USA

As far as we know Wedge Inserts, Relieving Angle Inserts, Shelf Inserts, Malleable Iron Inserts are not made anywhere in the United States. The ones we have seen are all imported. This creates problems with jobs that require all products be Melted and Made in the USA. An exception would need to be applied for by the fabricator or Project manager. Note: Our 5/8" Askew Bolts and the Stainless Steel Askew Bolts are made in the United States. The 3/4" Askew Bolts in stock are imported. We have made the 3/4 diameter in the USA in the past and can do so on special order.

Askew Head Bolt

Galvanized Surface

All stock Wedge Inserts and Askew Head Bolts are Hot Dip Galvanized.

Deep Stock

As mentioned above all the Wedge Inserts we know of are imported, mainly from China. Because of the lengthy order lead times, often as much as 4 months or more, The Steel Supply Company keeps a deep stock of all items related to this line. Regardless, if your project is calling for Wedge Inserts and Askew Head Bolts it is a good idea to contact us as early in the project as possible. We will do whatever is necessary to assure your products are on hand and delivered to your fabrication plant or jobsite in a timely and complete manner.


View Wedge Insert Estimating Guide

Tags: Askew Head Bolts, Wedge Insert, Relieving Angle, Concrete Wedge Insert, Malleable Iron Insert, Masonry Anchors, Shelf Angle, Lintel, Shelf Angle Insert, Relieving Angle Insert

Wedge Inserts, Shelf Angle Inserts, Some Installation Notes

Posted on Mon, Feb 24, 2014 @ 12:57 PM

Wedge Inserts are also known as Relieving Angle Inserts, Shelf Angle Inserts, Malleable Iron Inserts and Lintel Inserts. The photos and drawings in this article will provide an idea of what they are. To see additional photos and catalog listings click here

Here are some notes on the installation of Wedge Inserts. Bear in mind these are just general notes. We are not qualifies to provide actual instructions. The project manager and erector should be knowledgeable regarding the requirements for their project.

To see drawing of the stages of Wedge Insert Installation click here.

2 Foot Spacing

The plans for your job can show the Wedge Inserts at whatever locations the architect or engineer chooses, but many of the plans we see call for them at 2' intervals. So for a building with a footprint 200' x 200' the perimeter will be 800', hence a typical job will use 400 Wedge Inserts per floor. It is not uncommon for a building to require 2,000 or more Wedge Inserts for the project.

Minimum Concrete x Each Direction

To provide the required strength, the Wedge Insert requires a minimum of concrete below, above and to the side. See Fig. 1. Be sure this is indicated on your drawings.

Wedge InsertRebarRelieving Angle Wedge Insert

Both the Regular Wedge Insert and the Long Wedge Insert have a steel loop around the back. This is to insert rebar. This rebar is important in making sure the Wedge Insert will hold solidly in the concrete. The plans should show the rebar requirements and layout. See Fig. 2.

Taped Face and Nail Holes

During the Concrete pour liquid concrete will invade every space and move in any direction it can. It is important not to allow any concrete to seep into the Wedge Insert. Once hardened, it will block the movement of the Askew Head Bolt. This is why the Wedge Insert has heavy tape over the face. The tape alone will not stop the concrete if the Wedge Insert is not fastened tightly to the plywood form. Remember during the pour, the rebar will be shifting and can exert pressure to pull the Wedge Insert away from the form. Also, the mounting holes in back of the Wedge Insert will admit concrete to seep in if they are not covered completely. See Fig. 3.

Shelf Angle Insert

Fastener Selection

Once the concrete has cured the forms Plywood forms will be removed. The nail or screw used to fasten the Wedge Insert to the form will still be there, and the part that was in the plywood will be sticking out. This needs to be removed. Determine in advance how you will remove them and select a fastener with that in mind.  

Malleable Iron InsertIn Fig. 4 to the left the fastener ends have been removed. This could be done with a cut-off wheel. In that case care should be used not to remove the galvanized coating. This method will leave the remaining barrel of the fastener in the Wedge Insert cavity where the Askew Head Bolt travels. The erector should determine in advance if this will be a problem.

Another way to remove the fastener body is with a firm stike with a chisel near the back of the cavity. For this method the erector would want to select a very brittle fastener that will snap easily.

It is important the erector understands how the fasteners will be removed, and test that method prior to actual installation.

For drawings showing the steps in the installation of Wedge Inserts, Shelf Angle Inserts, Relieving Angle Inserts and Malleable Iron Inserts, click here.


View Wedge Insert Estimating Guide

Tags: Askew Head Bolts, Wedge Insert, Relieving Angle, Malleable Iron Insert, Masonry Anchors, Shelf Angle, Lintel, Shelf Angle Insert, Relieving Angle Insert, Wedge Inserts