Herald and news. [volume] (West Randolph, Vt.) 1878-1943, 1890-06-05
ROAD MAKING SYSTEMS.
Extracts from The Engineering ana
Building Records Prize Essay.

Rineerlng and Building hecoIus PAANo
ESSAY ON road making (by 5. c. Thomp-
son. New York; contain many valuable
facts:
Where curves are required make them
as fiat as possible, and on a first class
road. where long trucks or loads are
liable to come, only in extreme CASES
should it exceed curve Of fifty feet
radius
On mountainous roads it sometimes
becomes necessary to increase the curve
to a radius of twenty feet.
A man can walk mp slope of 100 in
100, and horse or mule can ascend an
incline Of 100 in TO, and it has been
found by experiment that horse pull
ing his maximum load on level can pull
but four-ffths as much if the slope is
made in 80, and this gradually lessons
until with a slope of in 10 he can draw
but one-fourth as much as his level load.
The maximum grade established by
the French Government Board of En-
gineers is in 90 The Holyhead road
in Wales uses in 80 as a maximum, ex-
cept III two cases. The road over the
Simplon Pass averages Leg ON Italian
side, and TO II ON Swiss side. with one
case of l to 10, and in this state several
turnpike roads are limited by law in IL.
In laying out road, with regard to
grades, have continuous inclination in
one direction, and do not allow any
counter grades, for, in ascending, each
foot descended on a counter grade means
Just so much more rise to be overcome.
Where long incline becomes neces-
sary it viii be found economical to
make the first portion the steepest and
decrease it as it ascends, and if the slope
can be varied by occasional level stretch
es the efficiency OF the road will be
greatly increased.
The roadbed ON steep slopes is subject
to greater wear from the feet of horses
in ascending, and is much more subject
to serious erosion by heavy rains.
Where the roadway is too wide it usu-
ally results in no part being kept in good
repair while if it was narrowed the
whole could be kept in first class condi-
ton at less expense, and a well kept road
of even twenty feet width is far prefera-
Bile to a road but half maintained Of
double the width.
In laying ont it may be advisable to
take strip considerably wider than the
intended roadbed, so as to provide for
possible contingencies in the future when
the land becomes more valuable. Lay
out sufficiently wide, but build only so
much as can be kept in thorough repair.
Tie essential requirements Of good
roadbed are that ii shall be practically
unyielding- smooth ON the surface, and
impervious to water, and without these
requirements there can be but little du-
rability.
No matter what the material may be,
a proper attention given to drainage viii
be found to be a good investment. both
as to first cost and future maintenance
IN this climate the worst enemies to
building or properly maintaining a road
bed are water aud frost, and if the FIRST
is kept out the second will have little or
no erect, as the surface viii not be
affected. and heaving viii be reduced TO
a minimum Again, if roadbel is thor
oughly drained it dries much more
promptly. and has less mud and less dust.
For earth roads. as commonly built,
there IS but little to be said and they
should only be tolerated III new coun-
try or where there is absolutely nothing
but earth Of which to make a road
Yet with earth alone a very passable
road can be made and maintained, if
sufficient care is taken to have it thor
oughly drained and the surface Of proper
shape
The persistent care with which some
Of the so called road surveyors in the
country excavate the material which
has washed into the cutters and replace
it upon the center of the road seems TO
indicate belief that the powers of man
surpass and are superior to those of ma
ture.
For surface draining, bitches should
be provided along each side Of the road
having sufficient fall to promptly carry
away any water that reaches them.
Where it becomes necessary to carry the
water across the roadway culverts should
be provided.
All drains should have a continuous
fall throughout their entire length, and
the size viii depend upon the inclination
and the amount of water they are ex-
| peoted to carry.
In portions of the country where
gravel is easily obtainable a very salts
factory road can be made by making the
surface for a greater or less depth OF
gravel
Prepare the foundation so as to allow
for prompt drainage, and shape AS the
finished road is intended to be: make the
sides Of the road planes, and not curves,
and then roll thoroughly to get a solid
foundation.
Put ON layer of gravel from six
inches to eight inches in thickness.
sprinkle thoroughly and roll till very
compact and firm. Next spread another
layer from four to six inches of gravel,
and sprinkle and roll till the desired
hardness and snOothness are obtained.