ANSWER TO REVIEW QUESTION 3
Softwoods are worked easily and make suitable material for structural framing. (para 26, a (2))
ANSWER TO REVIEW QUESTION 4
As shown under the "illustrated use" column of figure 2-11, special connectors are referenced by lettered
symbols. (para 2-8, b)(figure 2-11)
Section III. Concrete and Masonry
shear stresses and the concrete resists compressive
2-13. CONCRETE CONSTRUCTION
stress. The bars may be round or square in cross-
a. Concrete is a mixture of cement, water, and
section, have plain or deformed surfaces, and be
aggregate. Aggregate is classified as fine and coarse.
manufactured of mild billet or hard rail steel.
Fine aggregate refers to sand and coarse aggregate to
Welded reinforcing mesh is normally used to prevent
crushed stone or gravel. Mixed together in specified
cracks and checks in slab or wall concrete.
proportions, fine aggregate fills the voids in coarse
aggregate and cement and water form a paste that
(1) Plain and deformed bars. Plain bars
hardens to bond the aggregate together in a unified
have smooth surfaces. Deformed bars have lugs,
mass. Concrete is poured into forms while it is still
ribs, and projections of various types on their
plastic. Once hard, concrete retains the shape
surfaces that do not change the cross-sectional
imparted to it by the form.
dimensions, but provide a better mechanical bond
between the bars and concrete.
b. When steel reinforcing rods are embedded in
concrete, it is known as reinforced concrete. In
(2) Sizes. Table 2-2 gives the sizes, areas,
general, bar reinforcing steel embedded in the
and weights of plain and deformed reinforcing bars in
concrete is assumed to provide for all tension and
common use.
Table 2-2. Sizes, Areas, and Weights of Reinforcing Bars
61
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