The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1906-02-23

American Councilmen Will Seek
Excuse for Squandering Tax
payers Money.
ENGINEER SHOWS THEM UP
GEORGE Nj. BACON QUOTES AU-
THORITIES ON SUBJECT.

The proposed conduit grab will come
up this evening at a meeting of the
council committees on engineering and
sewerage. The prospects are that no
report will be agreed on tonight, as
| the councilmen are planning to visit
the conduit before taking final action.
At the meeting this evening the rea-
sons for the proposed changes, costing
| SIS, 900, will be discussed. Some excuse
probably will be asked from the city
| engineer for the step. It is proposed
to plaster the inside of the conduit,
increase the thickness of the cement
| and to cover the work with earth.
| George NJ. Bacon, the engineer who
Big Cottonwood conduit, was asked by
| The Herald yesterday If any such work
as is now proposed had been considered
by him and the reason for its rejection
| On the subject of plaStering the
inside of the conduit, on which the
| American" leaders propose to spend
| ST., 600, Mr.. Bacon said, in response to
questions:
I'm 1903 the annual convention of the
American Society of Civil Engineers
discussed at length the question of i'm
ciety's official conclusion:
This question of permeability is
one intimately related with the skill
with which the ingredients of the con-
crete are mixed together and placed In
position. All that is necessary to make
the concrete imrervious is to wash the
walls with grout.'
I'm the Big Cottonwood conduit"
Mr.. Bacon pointed out, ''grouting the
inside Of the conduit is called for In the
specifications. The engineers cOnclu-
sion pointed out that on the New York
aqueduct lime and cement wash made
the work practically impermeable. No
exception was taken TO these state
ments.
The Boston Aqueduct.
1.-THE Wauchusett aqueduct, which
brings 300, 0O0, 600 gallons of water into
the metropolitan district of Boston ev-
cry day had a Portland cement wash
applied to the brick sides and invert
for the purpose of making the mason
ry more nearly water tight
"BueI & Hill, in their treatise on
reinforced concrete, which Is the ma
teriaI used In the conduit here, state
that clustering as method of fin
ishing concrete surfaces deserves
mention for the purpose alone of
calling a warning against it's adop-
ton. 1t is practically impossible to
apply mortar in thin layers to a con-
crete surface and make it adhere for
any length of time"
Thickness of the Walls.
On the subject of increasing the
thickness of the walls of the conduit
from six TO eight inches, upon which
the American" leaders plan to ex-
pend s35, 900. Mr.. Bacon said:
1.-THE walls of the Big Cottonwood
conduit were figured out mathematical
{ ly, using a high factor of safety. In
creasing their thickness two mcnes WIFI
make them 20 per cent stronger, giving
, q factor Of safety only to be recon-
mended In case concrete is subjected to
heavy jar or vibration as in factory
construction. But even this high factor
of safety can be obtained more cheap
: ly by increasing the amount of steel
reinforcement. AS an example Of thin
walls the following are prominent:
"Aqueduct in Switzerland, six feet
three inches square; walls four inches
thick
!! Jersey City water supply conduit,
peight feet six inches in diameter; walls
seven inches thick
Harrisburg sewer, five by seven feet
in dimension; walls from five to sew
{ er: inches thick.
( Paris sewer, nine feet in diameter;
! walls four inches thick in tunnels.
1.-THE conduit here is three and a
S half by four feet in the clear"
Covering With Earth.
Y Concerning covering the conduit with
I earth, upon which it is proposed to
e spend about $4,000. Mr.. Bacon said:
mo competent engineer will deny the
: advantage of having the conduit COW
cred with earth throughout its entire
I length, provided the expense is not toe
II great The big savings made by cut
II ting across gulches on piers certainly
II more than offset the advantage Of COW
ering the remaining less than 10 pei
II cent of its length not now under
II ground.
III eff the sun and elements are to crack
Il and play havoc with the exposed por-
/ ton of the conduit, what will happen
H to the hundreds of reinforced concrete
II buildings erected in the east during
II the last few years? In view Of the fact
II that some OF these buildings are much
III taller than the tallest office building in
HI Salt Lake, the little fifteen foot spans
II of conduit seem hardly a new depart
Il ure to any one who is familiar with
II reinforced concrete
II AS to Leakage.
II 81 am not in possession of facts
enough regarding the conduit to com
II nlent ifltelligibly or it's behavior. Any
II one who knew of the difficulty Mr.
II Moran, the contractor, had last au.
HI turnn in getting competent labor could
III not dream for a moment of the conduit
ii being free from defects. and each de
III feet means leakage unless remedied.
HI The committee on engineering and
II sewerage of the city council, to which
II the proposed conduit grab has been re
II ferred. will meet tonight, but it il
IL hardly probable that it will agree OF
II a report before visiting the scene O
y operations