The San Francisco call., 1906-06-19
DISHONEST
MORTAR IS
To BLAME
Professor Nakamura Gives
Cause Of Damage by
Earthquake.
Says Lesson Of Disaster Is
One That Is Easily
Learned.
Defends Good Brick Build
ines as Being Safe
as Others.

Dishonest mortar-a corrupt con-
gfomeratioQ of sea sand and lime-was
responsible for nearly all of the earth
quake damage in San Francisco, says
DR.. I. Nakamura, professor of archi-
lecture of the imperial University OF
Toxic and one of the most distinguished
members of the committee dispatched
to this city By the Japanese Govern
ment to investigate the effects of tenn
blor and fire. After Investigations COW
ering a period of weeks, DR.. Nakamura
has completed his labors and will sail
on the Korea tomorrow to report his
conclusions to his Government.
Il find" said DR.. Nakamura yes
terday, that much of the damage to
San Francisco from the earthquake was
due to poor mortar and faulty con-
struetion, and the greater portion of
the damage to the class A buildings by
fire was the result of misguided use of
hollow tiling and so-called fire blocks
instead of concrete. 1t is an easy mat
ter. l have found. to design a building
that will be not only earthquake proof
but practically fire proof.
I'm the class A buildings the founda-
ton should receive the first and great
est attention. If the foundation is
solid half of the problem is solved. The
outside covering should preferably be
of brick, honestly cemented with hon
est mortar, or if sandstone is used the
bonding system. as represented in the
Claus Spreckels building. should be
employed. In this system every other
block is deeper than the preceding one
and is thoroughly cemented into the
brick wall behind. 1t was this system
of construction that prevented the
Claus Spreckels building from throwing
off its outer she'll when the earthquake
struck it.
"All of the steel beams and girders
ShOnld he inna in
this system was followed in the class
A buildings there was no structural
damage done the buildings by the fire,
but those that depended upon hollow
tiling. or expanded metal and plaster
, to project the frame suffered great loss.
The thing and plaster broke, either as
a result of the earthquake or fire, and
exposed the steel to the flames The
result was that in many instances the
steel became red-hot and telescoped.
practically running buildings that would
be structurally sound today had con-
crete covering been used.
"All floors should be of reinforced
concrete. Hollow tiling floors proved
a failure in almost every instance and
should not be employed The interior
walls should be of reinforced concrete
and covered with the usual plaster. In
those cases where hollow thing was
used on interior walls the face OF the
same broke OH ana caused great DAM
age. All heavy cornices and gables
should be prohibited Even when at
tached to the frame they are a menace.
but light metal corniees and gables
may be employed and when attached
to the steel skeleton are perfectly safe
and cannot be shaken down.
There has developed as a result of
the earthquake in San Francisco great
prejudice against brick buildings. How
ever, they are largely employed in
Japan, where earthquakes of greater
severity than the one experienced in
this city are not uncommon. The secret
of their success. however, lies in the
fact that good mortar is used The
mortar should either be composed of
one part cement to two parts of sand
or of one part cement, three of lime and
thoroughly wet before being laid. and
when the mortar has set under these
conditions a wall becomes practically
one stone.
II have examined your City Hall and
find that while the mortar used was
fairly good in some places it was very
poor in others. The mortar was poor
where the greatest damage resulted.
The use of isolated columns constructed
in sections also proved an inherent
weakness. These columns were not
properly tied to the main building
above and below, with the result that
they collapsed and pulled great sections
of the building down on top of them