EARL AND LOOMIS—STRENGTH OF BRICK MASONRY.              29
 

TRANSVERSE STRENGTH OF BRICK MASONRY.
 

By M. a. Earl, '93, and A. B. Loomis, '93, Civil Enoineering Course.
 

INTRODUCTIOK.

In spite of the fact that brick masonry is very generally used
in engineering structures, comparatively few experiments have been
made to determine its transverse strength. In fact, this strength has
not usually been counted on in designing, as so little definite knowl¬
edge was to be had concerning it. For instance, when an opening
for a door or window is cut in a brick wall, it is known that the
masonry immediately above is subjected to transverse strains. Trans¬
verse strains also come in walls subjected to water or wind pressure
and in tall chimneys. Brick arches, which theory shows would fall,
considered simply as arches, do not fall, and it is undoubtedly the
transverse strength of the masonry which prevents failure.

"Much surprise was expressed, at the time, at the comparative¬
ly enormous strength of some narrow strips of brick arches, 15 feet
span, and only 4f inches thick, tested by Mr. Fairbairn; but there
were no just grounds for surprise."* The surprising strength of
the arch was due to the transverse strength of the masonry.

The supports of masonry over doors and windows are some¬
times considered as supporting the entire weight of the masonry
above them. This involves the idea of fluid brick and is fallacious.
When a wall is ''green" it will have to be supported above openings,
but if built up slowly the supports may be removed in many cases as
soon as the lower courses have set. Knowing what modulus of
rupture can be relied upon, the computation is simple.
 

PART I.
 

EXPERIMENTS  BY  OTHERS.

Investigation shows the literature on this subject to be exceed¬
ingly limited. The experiments made have been few and poorly
performed.     The following references bear more or less directly

*Engineeri7ig, Vol. 14, p. 73.