Chapter 3 Flashcards
Types of wedge anchors
- Fully threaded
- Partial threaded
- Full-bodied wedge anchor
Types of conventional anchors
- Square-headed bolts
- Hex-headed bolts
Conventional anchors
- Usually embedded in the masonry during construction and require careful attention to bolt location and grip length requirements
- Usually made to the specific project requirements by steel fabricators or purchased from steel suppliers
- Availability and cost are generally based on demand and fabric requirements
Types of proprietary anchors
- Expansion anchors (wedge anchor, sleeve anchor, drop-in anchor)
- Adhesive anchors (self-contained adhesive anchor, site-mixed adhesive anchor)
Proprietary anchors
Typically installed after completion of construction, permit a larger degree of freedom in anchor placement
Bent bar anchors
- Frequently used in masonry construction
- J or L shaped
Plate anchors
Usually made by welding a square or circular steel plate perpendicular to the axis of a steel bar that is threaded on the opposite end
Through bolts
- Extend completely through the thickness of the masonry and are composed of a threaded rod or bar with a bearing plate located on the surface opposite the attachments
- Primarily used in industrial construction where aesthetics are not a principal concern, or in retrofitting existing structures
Anchor bolts
- Used as a means of tying structural elements together in construction
- Required to resist a combination of tension and shear loads acting simultaneously due to combinations of imposed dead loads, live loads, wind loads, seismic loads, thermal loads and impact loads
Tension
Tensile capacity of an anchor is governed either by the strength of the masonry of by the strength of the anchor material
Effective anchor embedded length
Length of embedment measured perpendicular from the surface of the masonry to the plate or head for plate anchors or headed bolts
Shear
Anchor capacity is governed by either the masonry strength or the anchor material strength
Combined tension and shear
Allowable combinations of tensile and shear loads are based on a linear interaction equation between the allowable pure tension and pure shear loads
Average factors of safety
4.0 for tensile test, 5.0 for shear test and 7.0 for combines tension and shear test
Edge distance
Min. distance of 300mm