Evening star. [volume] (Washington, D.C.) 1854-1972, 1907-09-28
GOOD BOND IN WALLS
SOME SUGGESTIONS MADE TO
WORKERS IN BRICK.

The majority Of engineers and some build
ers frequently leave the question of tond
in brickwork to the unhampered choice of
the working mason. Such casual proceed
ing, says Indian Engineering. Is seldom at
tended with any serious risk In case of
walls whose thickness is the length of a
single brick. for here the bricklayer will be
pretty certain to adopt either the Flemish
or the English bond, both of which are I'M
Objectionable In the majority of cases,
though the latter is distinctly the sounder
arrangement. When. however as is the
case in the majority of works which en-
gage an eng .neers attention, the thickness
much exceeds that Of singe brick, conse-
quences of such neglect in detail are fire.
quently deplorable We have seen large
masses of DrickWork-notably in lock walls
consisting of nothing but headers, if We
except those stretcners which appear on
the exposed face of the wall and which, of
coulse, occupy but a minute fraction of
the walls cross section. Such structure.
If We ignore the adhesion of the mortar,
has but little more longitudinal strength
than has a huge fagot of short sticks with
out that string which Is usually provided
by the Woodcutter.
1t is scarcely surprising, therefore, that
the majority of such walls develop trans
verse cracks, even when they are exposed
ment than is Incidental to ordinary care
less construction.
Main Requirement.
The main desiderata Of good bond are
three-(D The bricks should overlap in each
direction an aggregate extent which Is ap-
proxmately proportional to the bending
moment or shearing stress to which the
wall may be exposed in that plane: ca the
bond should not necessitate the cutting of
bricks; C3) it should be applicable to walls
of all thicknesses and yet sufficiently sim
pie to be easily learned by the ordinary
bricklayer. The ''Habri" bond pre-emi-
nently satisfies all these requirements; the
first two demonstrably, and, concerning the
last, we have never met a master who did
not readily comprehend the system as soon
as 1t had been illustrated in his presence by
the piling of few dry bricks.
In the Habri bond ever course in a
wall of indefinite thickness is essentially
identical with every other course. and con-
sists of cycle of three rows Of bricks
two rows of stretchars followed by one row
of headers. This arrangement In each
course is, however, shifted half a brick in
direction at right angles to the rows, as
compared with the course upon which it
rests, the direction of the shift remaining
constant throughout the walls height.
When. under the above clause of this rule.
row of headers would be divided by the
plane of a face of the wall. a row of half
bricks is not inserted, but row Of stretch
ers substituted
In the case of a wall half brick thick
this bond necessarily reduces-as do all
other bonds-to a wall consisting of stretch
ers only When the wall Is one brick thick
have course of headers only fol-
lowed by three courses of stretchers only;
the arrangement being here identical with
common English bond. which is undoubted-
ly the soundeSt arrangement in one-brick
wall under ordinary circumstances.
Where It Is Valuable.
1t is, however in walls exceeding one
brick in thickness that the vaue of our
systematic rule becomes evident. Starting
from the face an arch abutment of in
definite thickness would have in It's first
course one row of headers, followed by two
rows sof stretchers, and so on. The second
course would show one row of Stretchers,
followed by one row of headers and then
two rows of stretchers, the last three rows
being repeated indefinitely. The third
course would consist of two rows of
stretchers. followed by one row Of head
ers and so on. The fourth course would
have three rows of stretchers next the
row of headers and two rows of stretch
ers. This completes the cycle of courses.
the fifth course being Identical with the
first not only in arrangement, but also in
horizontal position. In the case of wall
under a vertical load, the direction in which
the half-brick step by which each course
has it's arrangement shifted compared
with that of its predecessor Is made has
no Importance. though of course 1t should
remain unaltered throughout the wal.
When, however. the wall is exposed to an
inclined thrust it is preferable to make the
the thrust. Thus in an arch abutment
the shifts are made from the face; In a
revetment wall toward it.
The name Habr is that of distributary
channel upon which the bond was first
employed some twenty years ago.