Fixing with steel anchors

What is a throughbolt and how to use it?

This is one of the most common types of steel anchors. The hole diameter matches that of the anchor.
There are two setting depths defined for throughbolts: standard and reduced, making it possible to freely adjust the anchoring depth to the fixture thickness.

When preparing for an installation job using a throughbolt, you need to prepare the following:

• drill bit of the right size,
• hand pump to remove drillings from the hole,
• hammer to drive the anchor in,
• torque wrench to tighten the anchor to the correct torque.

What are screw-in anchors and how to use them?

Also known as concrete screws or bolts, their operating principle is similar to that of wood screws. The anchor’s shape and the fixing method employed are the reasons why anchoring takes place along the entire length of the hole, making the most of friction rather than expansion forces. This makes concrete screws suitable for fixing in close proximity of edges and nearby anchors, which proves particularly important when installing elements such as railings or balustrades.

The screw-in anchors from Rawlplug come in as many as seven head variants, which significantly extends the range of their potential applications. Screw-in anchors also offer the possibility of fixture adjusting, e.g. when it has originally been installed crooked. According to the approval, we can loosen the anchor by up to 10 mm, correct the fastening, and tighten the screw into the concrete again without losing its load bearing capacity. The approval allows this to be done twice.

This is what you need for fixing with screw-in anchors:

• drill bit of the same size as the anchor,
• hand pump to clean the hole,
• impact wrench to tighten the anchor.

Shield anchors – fixing and applications

Shield anchors were actually the first to have been patented as mechanical anchors back in 1934, only to mark the onset of the entire industry’s further development.

With the unique design, shield anchors are suitable for use even in weak substrates. Additionally, they come in several variations, making it much easier to select an anchor for a specific application. 

Thanks to the long expansion zone, you can use this type of anchor in the most demanding substrates, such as cracked concrete, but also in solid bricks, precast blocks, or hollow core slabs.

Unlike the steel anchor types discussed above (throughbolts and screw-in anchors), the shield anchor requires using a drill bit of a larger diameter than that of the fixing. 

Fixing with shield anchors.

1. Drill a hole to the adequate diameter and depth.
2. Blow out drillings using a hand pump at least four times.
3. Remove the nut and washer, insert the anchor sleeve into the hole, and tap it with a hammer until it comes flush with the substrate.
4. Place the nut and washer on the threaded rod and, using a torque wrench, tighten them to the required torque.

The following table details parameters conditioning the choice of the drill bit size:

Hammer-in sleeve anchors – how do they work?

Sleeve anchors are typically used for installation of piping, ventilation, and cable tray systems. The design of this particular steel anchor allows you to use both metric bolts or threaded rods for fixing, as they can be screwed directly into the anchor. 

Fixing with sleeve anchors proceeds as follows:

• drill a hole using a drill bit with a special stop collar which prevents drilling a hole larger than needed,
• place the anchor inside the hole and hammer it in with a mallet,
• use the mallet to drive the anchor all the way through to make sure that it has been set correctly in the substrate,
• the conical section expands the anchor and sets it securely in the substrate.

Which steel anchor to choose?

When choosing the right mechanical fixing, consider the following parameters:

• substrate type – all mechanical anchors can be used in non-cracked and reinforced concrete, while some can also be used in cracked concrete;
• corrosion category – depending on where the anchor is to be installed and what weather conditions it will be exposed to, choose a solution of the right corrosion resistance category;

• fixture design – it is important to check whether the fixture to be installed can be installed using a specific anchor. For example, what may be required when dealing with certain loads is straight-through fixing or the use of a flat head bolt to come flush after anchoring, or even pre-installation using a threaded rod and a nut;
• load capacity and installation parameters – the anchor’s capability to transfer a specific type of load.