In selecting shim material, an important consideration is Fire Rating. For Concrete Contractors, shims often are used in the forms prior to pouring concrete. Since they will not be a permanent part of the structure any material that provides the necessary spacing should be acceptable. For steel Fabricators and Erectors, the shims are more often permanent and required to last the life of the structure. This requires proper material selection not only for Compressive Strength and Durability but also for Fire Rating.

Note: For the purposes of this article we will refer to them as Wedge Inserts. They are also known as Lintel Inserts, Relieving Angle Inserts, Shelf Angle Inserts, Malleable Iron Inserts and Concrete Wedge Inserts.

The typical Hillside Washer, also known as a Bracer Rod Washer, is made from ductile iron and serves the purpose of providing a perpendicular surface regardless of the angle of the Turnbuckle Rod they are anchoring. As shown in the illustration, the oval surface will allow a nut and washer to seat itself at the proper angle just by the tension created when tightening the turnbuckle.

The typical Slide Bearing design used in Steel Fabricating, whether Teflon®, Virgin PTFE or Fluorogold®, is 7/32” thick. This is comprised of a 1/8” thick steel backing plate and 3/32” Teflon® bonded to it. Most often, they are in pairs with the Teflon® surfaces in the middle as shown in the illustration.

Galvanized Vent Hole Plugs, whether Aluminum or Zinc, will seal themselves very tightly with normal installation. The slight taper in the body allows the plug to be driven into the hole like a wedge. Each successive hammer strike drives the plug in slightly further and makes it a little tighter. As well, both Aluminum and Zinc Vent Hole plugs are relatively soft, malleable metals. While being driven in, they conform to the minor irregularities of the hole. In this way with normal installation, the plug is sufficiently tight to remain in place for the life of the fabricated steel.

Whether Slotted Shims or Solid Shim Plates, common selections for shim material include Plastic, Carbon and Stainless Steel. Each has a specific benefit and when used properly, can provide adequate service for the entirety of the structure’s life.

A question frequently asked, regarding the placement of EZ Sleeves, is the required depth. In actuality, the required depth does not change whether the hole is created by using EZ Sleeves before pouring concrete or Core Drilling after the concrete has cured.

Whether it is PTFE (Teflon®) Slide Bearings, Elastomeric Vibration Absorbing Bearings, AASHTO grade Neoprene Bearings or any other bearing, it is imperative that the substrates are accounted for if the bearing is expected to function properly and serve to the longevity it is capable of.

We have recently seen an increased focus on the topic of anchor bolts and threading. In a previous blog entry, we discussed considering the thread length of Anchor Bolts with excess thread on the exposed end. Based on the intentions and needs of particular steel fabricators, this topic may or may not be applicable to your business (of course, we’ll manufacture the Anchor Bolts to any specification required.)

The Steel Supply Company manufactures Anchor Bolts and Turnbuckle Rods every day… and that’s also how often we see Anchor Bolt Drawings calling for threads that appear unnecessarily long. With regards to the exposed end, extra thread length is requested so the fabricator can be sure there will be sufficient thread for the washer and nut to “bottom out” regardless of any problems with positioning.