The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1906-09-16

upon by tho present city administra.
interior Of the conduit with a cement
plaster. Tho conduit, as originally de.
signed, was Objectionable for the fur
ther reason that in case tho animal or
vegetable matter passed over the ir-
regular surface Of the concrete, it would
then have been carried to the reservoir,
Under the present construction these
VIII be carried along to mud drums and
blow-otts, which have been placed at
Intervals on the conduit, specially for
their discharge. These drums and blow
OILS were not in the original design and
consist of tanks ten feet deep, extend
ing below the bottom of the conduit
and properly fitted with valves for the
emission of accumulated matter.
Necessary to Prevent Leakage.
Further, from q mechanical point Of
view, the cement plastering was con-
sidered necessary TO prevent leakage.
The concrete, as it stood in the conduit,
was porous, and though at some future
tlme 1T might possibly have become
water tight, by the accumulation of silt,
before this could take place there was
great danger, especially in cases where
the conduit is built on what is termed
made - ground, that tho foundation
would be undermined by the leakage
which would probably lead to the de,
structlon OF part, if not all, Of the con-
dult. This danger is now entirely elm
mated by the plastering of the conduit.
Ihat the danger was not imaginary was
fully proved by the excessive leakage
of the conduit when the water was
turned into it from the Big Cottonwood
creek, in order to ascertain if tho con-
dult, with its concrete finish, was prac-
ticable. The City Councilmen went in
body TO the conduit, Mt that time,
and had ocular demonstration of the
fact that the concrete was not water
tight.
A still further reason for the con-
dnit's being plastercd with cement is
the decreased friction Of the water
when flowing through the conduit over
tho capacity Of the conduit to n large
extent.
1t has been stated by some parties
that cement plaster will not adhere to
concrete after the concrete has become
set. The fallaoy Of this statement can
be shown both by the Parley's creek
conduit and the city's gravity outlet
sewer. To prove how tenaciously ce.
ment plaster will cling to concrete,
when properly applied, it is only neces.
sary to state that since the completion
of the gravity outlet sewer, some ten
years ago, at the beginning of each
month heavy steel scrapers have been
sent by the force Of the sewage, from
Fifth South street, or the beginning OF
the gravity sewer, through each section
to the extreme end of the sewer, with
the result that the cement plaster which
was put on the concrete ten wears ago,
after the concrete had set, is still in.
tact today and shows no signs of either
abrasion or pecling off.
The estimated cost for the cement
plastering of the conduit was $4,000
square yards at 80 cents per square
yard, $l7 500. This price was additional
to the figure stated on the original con-
tract for grouting. the grouting not
being used, as the cement plaster took
its place.
Strengthening the Walls.
In the original plans the walls of the
conduit were six inches thick. The
roof was variable in thickness, from