CRSI |
ENGINEERING
DATA REPORT NUMBER 39 |
REINFORCED MASONRY |
 A
SERVICE OF THE CONCRETE REINFORCING STEEL INSTITUTE
933 N. Plum Grove Rd., Schaumburg, Illinois 60173-4758 |
INTRODUCTION
Masonry construction uses a variety of
materials such as natural or artificial stone, concrete or clay block or brick, glazed
file and glass. The binding agent is a cementitious mixture of portland cement, hydrated
lime, sand, and water called mortar. Other materials such as wire, lath and reinforcing
bars should be used to add structural strength.
Archeological evidence indicates masonry
construction dating back 10,000 years in a variety of uses. The Great Wall of China, the
Pyramids of Egypt and the Roman Aqueducts are examples of the broad applicability and
durability of ancient masonry structures.
The major contemporary use of masonry is
in wall construction such as basement, retaining, screen, veneer, fire walls and bearing
walls (to name a few).
Following are answers and illustrations
to some of the most asked questions regarding concrete masonry construction.
Q1: In building
construction, what are the most common types of masonry materials?
A: Hollow concrete and hollow clay masonry units (blocks), fired clay or concrete
bricks and hollow clay tile.
Q2: What do the terms
WYTHE and CAVITY WALL mean?
A: "Wythe" is the term used to describe the number of layers in the width
of a masonry wall. For instance, a multiple wythe wall may have an outside facing of
brick, an air space, a layer of closed cell rigid insulation, and an inner wythe of
concrete masonry units (CMU). A "cavity wall" is a two-wythe wall with an air
space gap (or cavity) between the wythes.
Q3: Why is masonry a
common building material?
A: Masonry construction lends itself to architectural variations of shape and
color. It uses locally available materials and labor, and is relatively easy to build. It
has a relatively large load carrying capacity. Masonry construction is fire resistant, and
provides thermal and acoustic insulation.
Q4: What is the most
widely used type of masonry for structural purposes?
A: Concrete masonry units (CMU), either solid or hollow. A two-cell unit is most
common, although a three-cell unit is also available.
Q5: What are the
dimensions of CMU?
A: The usual height of a block is 7-5/8 in. with a
length of 15-5/8 in. Using a 3/8-in. mortar joint, the finished dimensions are 8 in. and
16 in. Block widths most often used are 7-5/8 in. (8 in.) or 11-5/8 in. (12 in.), but 4,
6, 10, and even 16 in. may be furnished.
Q6: What are the most
common shapes of CMU?
A: Refer to Figures 1 through 10 for isometric views and descriptions of use for
the various shapes.
Q7: Are there material
standards for masonry?
A: Yes, the American Society for Testing and Materials (ASTM) publishes standards
governing the material requirements for block, brick, mortar, reinforcement, and grout.
© Copyright 1993 by the Concrete Reinforcing Steel Institute
