Overview of fixing technology
High Performance Anchors
Mechanical anchors are fast, reliable & cost effective anchors. They have been used since the invention of the Rawlbolt - the first ever mechanical fixing, in the 1930's. As substrates (the building material) evolved such as the introduction of reinforced concrete, engineering brick and lighter materials including panel building materials (plasterboard), so has fixing technology. There is a fixing for most substrates with many producing exceptional load capacities. Mechanical anchors are amoungst highest performers and are immenseley strong.
When fixing with a mechanical anchor the selection of the fixing is based more on the substrate than when using chemical resin anchors. This is due to the anchors expanding within the hole and putting stress onto the local material. If the material isn't strong enough the fixing would damage the surrounding material and a possible anchor failure would occur.
Safe Working Loads
The terms safe working load (S.W.L) is the maximum load each fixing can lift, suspend or lower safely. It is often well below the ultimate failure load and is also often calculated with a safety factor (typically 2:1 or 3:1) for even greater protection. Individual anchors will state any safety factor calculated for that particular product.
Tightening of Fixings
Nearly all mechanical anchors are torque controlled and should be tightened to the required torque using a torque wrench, which ensures that the clamping force is greater than the safe working loads or put simply - is installed correctly.
Different types of high performance anchors include:
Wedge Anchors
Wedge anchors, drop in anchors, Hammersets, HKD's or Redheads as they can be known, are, apart from one of the most colloquially different named fixings, probably one of the most commonly used within the construction industry. Most commonly used in conjunction with 3m studding to fix services such as cable tray, channel support systems, pipes, ventilation systems, sprinkler systems and suspended ceilings to the underside of a non-cracked concrete ceilings, wedge anchors provide a permanant threaded fixing, which allows bolts or studs to be removed without damaging the anchor. They are installed with a manual wedge anchor setting tool or mechanical setting tool used in an SDS-plus hammer drill, wedge anchors are quick to install and a very cost effective fixing. They are available in both steel zinc plated and stainless steel A4 316. Rawl Wedge Anchor Technical Information.
Lipped Wedge Anchors
Similar to a standard wedge anchor, lipped wedge anchors are used to install services below a non-cracked concrete ceiling. The rim ensures that the anchor remains flush with the surface in case the operative has drilled the required hole too deep.
Rawlok Sleeve Anchors
The Rawlok® is a torque controlled expansion medium duty anchor, comprising of a split sleeve and a bolt incorporating an expanding wedge. It is a through fixing, which means that the hole in the substrate can be drilled through the pre-positioned fixture, eliminating the need for marking out, which in turn ensures fast and simple installation. They are available with a bolt or nut top and in steel zinc plated and stainless steel grade A4 316. Sleeve anchors are ideal for installation of stadium seating, hand rails, satalite dishes & aerials, fencing, signs, shutters and garage doors. Suitable substrates include concrete, solid block, solid brick and solid stone.
Rawlbolt Shield Anchors
The Rawlbolt is the World's most popular expanding shield anchor. Rawlbolt's are easy to use and have a good load carrying capacity. They are suitable for a variety of substrates including concrete, brickwork & stone, which makes them a good general purpose anchor with excellent tolerance to variation in hole size. They are available with a nut top called Bolt Projecting, bolt top, which is called Loose Bolt and with an forged Eye or Hook. Its also supplied with just a shield anchor only so that you can add your own bolt and vary the fixture thickness as required. They are ideal for roller shutter doors, fire doors, steel work, security grills, machinery plus pipework and duct work supports.
Rawl R-XPT Throughbolt
The Rawl R-XPT Throughbolt range has been developed to meet the changing demands of the market in terms of approval levels, ease of fixing and product quality. The versatile through fixing can be used in a wide range of applications in concrete 20 N/mm². Available in steel zinc plated, hot dipped galvanised and stainless steel grade A4 316. Ideal for cladding restraint, curtain walls, balustrading, barriers, handrails, racking, structural steel work & bollards. The Rawl R-XPT throughbolt has an European Technical Approval (ETA) ETA-08/0339 for use in cracked and non-cracked concrete.