Building Design and Construction Handbook - Merritt - Ventech!

11.138 SECTION ELEVEN
Metal anchors of various types are used in building construction. Each type is
specifically shaped, according to the purpose served. These include anchors for
securing stone facings to masonry walls, anchors for fastening marble slabs in place,
column anchor bolts set in foundations, and anchor bolts for fastening sills to
masonry.
Joist hangers are used for framing wood joists into girders and for framing
headers into joists around stairwells and chimneys.
Various types of expansion bolts, screw anchors, and toggle bolts are available
for securing fixtures, brackets, and equipment to solid material, such as masonry,
brick, concrete, and stone. Anchors also can be had for fastening to hollow walls,
such as plaster on metal lath in furred spaces and hollow tile. The best device to
use depends on the requirements in each case.
For use with practically any materials, including soft and brittle ones, such as
composition board, glass, and tile, fiber screw anchors with a hollow metal core
find a universal application. These plugs with braided metal cores possess many
advantages: They can be used with wood screws and with lag screws. The flexible
construction permits the plug to conform to any irregularities. Because of this elastic
compression, the fibers are compressed as the screw enters. Screws can be unscrewed
and replaced. Shock and vibration have no effect on gripping power. The
plugs come in about 40 sizes to fit anything from a No.6 screw to a 5 ⁄8-in lag screw.
In practice, a hole is drilled first, the plug is driven into it, and then the screw is
inserted, expanding the plug against the sides of the hole.
For some fastenings, one-piece drive bolts are hammered like a nail into prepared
holes in masonry or concrete. Other types of expansion bolts have expansion shields
or are calked into place. The expansion shield is expanded in the hole by a tapered
sleeve forced against a cone-shaped nut by the tightening of a bolt threaded into
the cone. These types are not recommended for soft or brittle materials.
For thin hollow walls, toggle bolts equipped with spring-actuated wings are used
(Fig. 11.89). The wings will pass into the hole in folded position. After entering
the hollow space, the wings open out, thereby obtaining a secure hold.
For fastening lightweight materials to nailable supports, stapling machines are
extensively used. In one patented system, for example, staples secure acoustic tile
to wood furring strips. In this system, invisible fastenings are obtained by using a
full-spline suspension for the kerfed pieces of tile and a special stapling machine
adjusted to function at the proper distance below the furring strips. The machine
staples the splines (at the joints of the tiles) to the supporting strips, giving a speedy,
economical, and secure fastening.
11.70 NAILS
Wire nails, made of mild steel, are commonly used for most nailing purposes.
Cylindrical in shape, they are stronger for driving than cut nails and are not so
liable to bend when driven into hardwoods.
Cut nails, sheared from steel plate, are flat and tapered. They have holding
power considerably greater than wire nails. They are usually preferred to wire nails
for fastening wood battens to plaster; also in places where there is danger that the
nails may be drawn out by direct pull. Cut nails are frequently used for driving
into material other than wood. They are generally used for fastening flooring. When