Evening star., 1897-03-04

District specifications for quality. On the
smaller sewers the contract price Is usually
for the linear foot of completed sewer. but
on the largest sewers the contract Is gen.
orally by the cubic yard Of material in the
sewer. All contractors must make eigh.
hours q labor day. Inspectors are paid -
per day, the amount paid being included In
the cost Of the sewer upon which they are
engaged.
In all work done by hired labor the day
is of eight hours. ordinarily from am. to-
II m. and from 1 PM to pm; but IN
late fall and early spring work begins at
I:30 am, with half an hour intermission al
noon time. The wages paid are all by the
day. and are as follows: Foreman. 81: la
borers, frst-class. $l.I5: second-class. $l.5o;
masons and bricklayers. 81: watchman.
$50; water boys, 30 cents; two-horse
wagon. with driver, $3.50; one-horse cart,
with driver. $1.75 The foreman Is respon-
sible for all tools belonging to the District
used by his party, and for all material is
sued for use in construction of the sewer.
and that all work is properly performed.
The first-class labOrers are generally those
engaged at the bottom of the trench where
the throw is hardest, and in mixing and
handling concrete.
The materials used in all sewers built by
hired labor are purchased by the District
in large quantities by contract, and stored
in the District property yards. The yards
are five in number, adjacent to the rail-
roads or water front. and each contains
the materia! which can be placed in with
the least haul from the point of unloading.
such hauls being. a rule, less than 800
feet.
The sand used is of exceptional quality,
being nearly pure silica, of sharp. reg
ular grain, obtained by dredging in the Po-
tomac, and is delivered in a condition that
would be termed washed in most locali-
ties. Two sizes are used-the coarser for
concrete and the finer for brickwork.
The gravel is used for concrete Broken
stone. at $3.50 per cubic yard. was formerly
hJlf no in
purchase price by using gravel. as well as
other advantages following it's use. which
are stated in describing the construction
of sewers, have caused it to be employed
exclusively in the department. All pipe
larger than S-inch is of the ring pattern
that is, without bell ends. 1t is found that
the bottom of the sewer, with this pipe,
can be MADE much more even and free
from projections due to Irregularities of
circumference. The timber used for braces
and snoring is Virginia pine, costing $3.50
per 1000 feet. and can be ordinarily used
about eight or ten times.
This city has had great trouble with the
pipe sewers laid about twenty years ago,
and very many of them have to be re-
placed entirely, the expense of doing SO
without interrupting the flow Of sewage
making the replacing sewer cost more than
one of the same size laid as a new one.
The active cause of the failure of these
sewers Is root intrusion. but the primary
causes are several, Cne being lack of proper
the grade having been tested at intervals
of 100 feet, and guessed at for the inter
vening interval, and if any obstacle, such
as boulder or stump, was encountered in
the trench, the sewer was simply laid
around it or over it. Another was careless
ness in jointing, the pipe having been
simply laid in the bottom of the trench
without any particular care to see that
each section occupied its proper position.
This effect has doubtless been increased by
the joints and forcing the pipes apart.
Washington streets. with their width.
fine pavements and magnificent lines of
shade trees. are models for the world: but.
owing to the width and expensive pave
ments, 1t has been necessary to place most
of the pipe sewers under the sidewalks,
where they are most exposed to the action
uf the rec roots. This condition of affairs
fen iei- necessary in sewers now built a
degree of protection for the joints that
would be extravaganza in most cities in
many cases where the roots have entered
the sewers they are cut out and the ;ntc
rior of the sewer freed in this manner.
This. however, affords but temporary re
lief, ard as the larger part of the o.d sew
ers a,e crooked, OILY a short dis:aYce from
the nan-hcle can be reached, and it fol-
lows CT necessity that the sewe~ must he
rebuilt. II has been found that the sof:er-
| wooded and -ncst rapidly growing trees sp-
pear 10 cause the most trouble.
The sewerage system of the future how :
ever. promises great things. Several years
ago Congress appropriated money for an
investigation of the subject by competent
engineers. and this report, with the rec
concentrations. has in the main been
adopted Sy the District. All sewers that
are laid now or estimated for are based
mainly upon the report of the engineers.
| and in a few years Washington will be in
| position to take its place among the best
| severed cities in the world.