The Topeka state journal. [volume] (Topeka, Kansas) 1892-1980, 1895-10-26

high. The next application was to
tubes aud sewers and then bridges, and
the last application was to fiat floors.
The advantage of concrete lies in its
durability, and this may be shown by
few examples such as the old Roman
conduits, aqueducts. and other old Roman
structures which have stood for centu-
ries.
The bath of Diocletian rs feet span)
and the para bolic main aisle in ST. Peters
Isl feet span and $50 feet rise) are com
paratively modern examples cf the dur
ability OF concrete. The bridge built
near Ulm, Germany, by DR.. Leube.
which has $50 feet span and crown of
2-3 inches, proves conclusively that
durability is not the only advantage in
concrete. but shows that it is a very
elastic body.
From this same bridge and its tests we
find that the cohesion between iron
and concrete is GAO pounds to the square
inch, and that it acted like glue when
hardened. In all cases where the con-
crete and steel or iron or the concrete
alone is used, it is found that it grows
better and stronger with time, and is not
affected by frcst or heat. The dead
weight that concrete can stand per foot
is greater than that of any other material
of the same thickness.
ne IOuDQdklOuS "a LUIS DFlQU0 over
the Kansas river on Kansas avenue will
be the same as for any other bridge, viz:
piles. tim Der and rip rap. The piers are
to be of Portland cement, Aeglomere
concrete. and to be solid monoliths. The
superstructure is to be. of steel girders
bent in the form OF the arch, and bedded
in and filled between with the above
named concrete. The roadway is to be
paved and the sidewalk to be tagged.
As this is to be a county bridge no pro-
vision need be made for the street cars
Should future needs require that they
have "a permanent structure, a single
track of nine feet in width could be ad-
ded on the outside of the down stream
sidewalk. This placing the car track
the width of the sidewalk from the road
way would lessen the liability of frig ht-
ening horses. That single track would
suffice will be seen when we consider
that at the rate of twelve miles per hour
a car could easily cross in less than forty
seconds.
In order to rightly understand the
material of which the bridge is to be
made, We must dismiss from our minds
the idea that it is mixture of cement
sand and stone of which we have knowl-
edge of having been used for the found :
alton of street paving in this city. The
nearest approach possible to its charact-
er is to consider it of the nature of cast
iron with au added advantage that it can
be moulded cold in leisure1y manner.
but which in addition to its ability to re-
sist compression there is a property in
common with stone that possesses ten
sile strength and elasticity in common
with cast iron.
The Melau system requires materials
of proper quality and properly selected,
VIZ: Portland cement of uniform quality,
clean, sharp sand, broken stone, the pro-
per sizes and washed. 1t is then sprink-
led with the required quantity of water,
put into a machine which mixes them,
forming a pasty mass. This is put into
the moulds in layers and made thorough
ly compact by ramming, forming a
homogeneous stone like substance. By
ramming, the volume is reduced by 90