The Evening statesman. [volume] (Walla Walla, Wash.) 1903-1910, 1904-12-02
PAPER PREPARED BY PROFESS
soR WALLER OF STATE AGRI-
CULTURAL COLLEGE.
Pead at the Good Roads Convention
Held in WaIIa WaIla This
Week.

Professor o. L. Waller, irrigation
engineer at the Washington agricul-
tural experiment station, which was
read yesterday morning at the Coco
Roads convention.
Your committee did we'll when il
saw fit to discuss minor highway
structures The large number of small
structures, as, culverts found on our
highways is very noticeable. A casual
observer will notice that they are
frequently demanding repairs. Usually
they are constructed without suitable
abutments or planking to protect the
sidewalks and when the high water
comes they are undermined either en-
tirely or partially. Sometimes they
are left in this semi dilapidated con-
dition to be a menace to horses legs
and wagons crossing them. In few
cases do minor culverts really rot out.
And where they do, their average life
is not over eight to ten years. The
lumber would really last little longer
in reasonably dry place, but under
road conditions it is alternately soaked
and dried so frequently that it soon
opens weather checks and promotes
decay Even railroad culverts which
are always made out of ties or equal
ly strong timbers are replaced about
every six to ten years.
However, the average life of high
way culverts is much less than eight
to ten years as suggested. The annual
lumber bill for culverts for an aver
age county would likely surprise a
taxpayer In recent years the rail-
roads, and in this state some Of the
counties have commenced to replace
their culverts with tile. One county
has a standing contract for all the
second grade tile turned out by
leading manufacturer When tile are
once properly placed that culvert is
fixed for all time and there should be
no more bills for repairs. Tile should
have from eighteen to twenty-four
inches of dirt over them, so the Inn
pact from loaded wagons will not
crush them. If so great a depth is not
possible, then they should be covered
with a few inches of dirt free from
stone, upon which may be placed some
old planks or any kind of lumber
that will take care of the shock until
the rains and traffic have thoroughly
settled the dirt around and over the
tile. After placing the planks finish
filling the trench, putting on plenty
of dirt SO mud holes will not form.
The ends of the tile on each side of
the road should be protected with a
wall which should be let we'll down in
the soil to protect the tile from be-
ing undermined and washed out. Such
a wall should be about two feet thick,
and may extend up to the level Of the
roadway. When no walls are provided,
the tile must be carried out farther on
the sides and be then exposed to
danger from being broken by wagons
and small boys. When walls are pro-
vided and the tile is we'll below the
grade of the road, smaller tile. may be
used allowing the water to be
damned up over the uppe- end of
the tile and thus to flow through under
pressure. When water is damned up
twelve inches over a twelve inch tile
it will discharge about fifty per cent
more water. At the lower end where
the water flows from the tile the bed
of the stream should be protected with
cobble stones to keep the eddies
formed at that point from washing
out the wall and from destroying the
structure. The joints of the tile should
be packed with cement or with oakum
soaked in tar or hot asphalt. .rne
joints can not be left open. thew some
times are, but such a plan allows the
water under pressure to be forced
through them and to wash awav the
dirt around the tile and so undermine
and destroy the structure
Only on new and temporarily To-
Gated roads should cheap timber
structures be allowed. When the To-
cation and final grades of road are
fixed then there should be no delay in
putting in permanent culverts of the
type suggested. Where more water is
to pass through than will go through
one line of tile two or even more
lines may be placed side by side.
When larger water way is required
than can be provided by this method
the writer believes reinforced con-
crete arches can be economically
used
A discussion of reinforced concrete
arches would he intoroc<;,- -.