Concrete Fastening General Information

Concrete Anchors and Fasteners

General:

Anchors and fasteners are available in a wide variety of types and sizes. The type and size needed for a particular application depends on a variety of factors including load level, direction of load (tension, shear, or a combination of the two). Other factors are environment (shock and/or vibration) and characteristics of the material into which the fastener is to be imbedded (new concrete, old concrete, concrete or cinder block, plaster, dry wall, etc.)

Fastening - is when a fixture needs to be connected to another, but subject to minimal amount of stress - for example, hanging a small picture, towel rack or mirror.

Anchoring - is when a fixture needs to be connected to another, but subjected to appreciable stress and vibration - for example, steel beam to concrete or guard rail to concrete.


Determining Correct Fastener:

The following questions must be answered before a correct fastener can be selected.

1. What is the base material and its density?

There are two types of base material;

Hollow Core - drywall, plaster board. sheet rock, particle board, wafer board,
plywood, plaster and lath, tile, glass, metal, fiber-glass, plastic and concrete block.

  1. Drywall: A low density material formed between sheets of paper and used primarily for covering studded walls and ceilings. Exhibits relatively low pull-out resistance.
  2. Plaster and Lath: Thin wooden strips (lath) were nailed to the studs or ceiling beams and low density plaster was applied over them. Exhibits relatively good pull-out resistance.
  3. C. Hollow Core Concrete Block: Commonly used in basements and commercial properties. Exhibits relatively high pull-out depending on compression strength of the block,

Solid Core - concrete, brick and mortar, stone, solid cinder block and wood.

  1. Solid Concrete: Exhibits the highest pull-out resistance, but requires a suitable carbide bit than meets ANSI standards.
  2. Stone: Since there are a large variety and different types, first identify the hardness and characteristics. Match up with the type of anchor needed.
  3. Brick or Mortar: like stone, it will vary from hard (brittle) to soft. In hard brick anchors with low-impact and/or low- torque are recommended. In soft brick, a draw-up anchor is recommended, i.e. sleeve anchor, machine screw anchor.

There are three degrees of density and strength of base materials; Low Density -
weak resistance to stress, i.e. drywall and cinder block. Medium Density - moderate
resistance to stress, i.e. plaster, tile fiber board and particle board. High Density -
significant resistance i.e. concrete, concrete block, stone.

Resistance to stress will vary within density and thickness of the base material. Age and manufacturing standards for material will result in different failure points for each anchor.

2. What is the thickness of base material?

How thick the base material is, will help identify the type of anchor as well as the
embedment allowable.

For Hollow Core base material it is critical to have the right length anchor so as to
be able to secure tightly. For Solid Core base material the embedment of anchor can
not be closer than five (5) anchor diameters, because its an unsupported edge and
holding values will be effected.

3. What is the size and weight of the fixture to be fastened?

If a fixture weighting 100 pounds needs to be fastened/anchored and the safe working load of the anchor selected is 50 pounds, at least 2 anchors will be needed to safely secure the fixture. Additional anchors may be warranted; not because of weight, but because of the bulkiness or size of fixture. When in doubt, always use more anchors.

4. What is the location of the fixture to be fastened?

Will the fixture be outside and subjected to the elements, inside, on a wall, suspended from a ceiling or fastened to a floor. Will the fixture be close to an unsupported edge. The distance between anchors is critical. If installed to close to each other, the interaction of forces between fasteners will reduce the holding power of the anchor in the base material. As a general rule, the anchor & fastener industry has established the following minimum spacing standards: Ten (10) anchor diameters between anchors, five (5) anchor diameters from the edge.

5. What kind of stresses may be on fixture once fastened?

The type and size of anchor or fastener suitable for a specific application depends
in part on the type and level of stress imposed on it. Five stress factors, illustrated
below, should be considered.

Tension:

Where a force acts in line with a Fastener, tending to pull it out. Ceiling mounted fasteners, as shown are subjected to tension. But so sometimes are fasteners that are mounted on walls and floors


Shear:

Where a force acts at right angles to a fastener, tending to shear it off. Wall mounted fasteners, as shown are subjected to shear stress. But so sometimes are fasteners that are mounted on ceilings and floors.

Impact:

Occasional or repetitive impacts subject fasteners to stress over and above that resulting from normal tension and shear forces. The railing at right would undergo such impact loads.


Vibration:

Over time vibration will stress fasteners and the base material; Vibration stress can be induced by near by heavy machinery, railroad, automobiles or truck traffic and wind.

Combination:

In some cases, fasteners are subjected to two or more of the forgoing stresses. The example at the right fasteners supporting drapery rods. The fasteners are in both tension and shear as well as vibration and shock stress.


Types of Anchors and Fasteners

1. Mechanical Fasteners: Best for hollow core materials.

Mechanical fasteners open on the back side providing the greatest holding
power for hollow wall applications such as drywall, plaster and lath, and hollow
core concrete blocks.

Toggler Bolt
Toggler Bolt
Toggler
Toggler

2. Expansion Anchors: For solid core material.

Expansion anchors produce a friction hold when expanded or wedge inside a hole.
Their holding power is enhanced in concrete because the concrete will not “give”
like drywall or plaster. Typically employed in solid-core materials-- concrete, brick
and mortar, stone, solid cinder block. Heavy to light duty.

Wedge Anchor
Wedge Anchor
Sleeve Anchor
Sleeve Anchor
Drop-In Anchor
Drop-In Anchor
Machine Screw Anchor
Machine Screw Anchor
Leadwood Screw Anchor
Leadwood Screw Anchor
Single Expansion Anchor
Single Expansion Anchor
Double Expansion Anchor
Double Expansion Anchor
Lag Shield Anchor
Lag Shield Anchor
Nylon Nail-It Anchor
Nylon Nail-It Anchor
Metal Hit Anchor
Metal Hit Anchor
Split Drive Anchor
Split Drive Anchor
TapCon Screw Anchor
TapCon Screw Anchor

Back to Top
tf :: 888.498.5747 | f :: 216.357.7435 |

ph: 888.498.5747
fx: 216.357.7435

Secure shopping: All online purchases secured by Thawte.

Visa, Matercard, Amex accepted.

Visa, Matercard, Amex accepted.