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A Textbook on Civil Engineering



nternational Correspondence Schools



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A TEXTBOOK



ON



CIVIL ENGINEERING

International Correspondence Schools

SCRANTUN, PA.



SURVEYING

LAND SURVEYING

MAPPING

RAILROAD LOCATION

RAILROAD CONSTRUCTION

TRACK WORK

RAILROAD STRUCTURES



5780



SCRANTON
INTERNATIONAL TEXTBOOK COMPANY

B-3



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Kurt F.Wendt Library

Urtversity of Wlsconsip - Madfsoft

215 N. Randall Avenue

Madison. Wl 53706-166S



Copyright, 1897, 1898, 1899, by The Colliery Engineer Company.



Surveying : Copyright, 1896, 1900, by THE Colliery Engineer Company.

Land Surveying : Copyright, 1896, 1900, by The Colliery Engineer Company.

Mapping: Copyright, 1895, by THE COLUERY ENGINEER COMPANY.

Railroad Location : Copyright, 1895, by THE COLLIERY ENGINEER COMPANY.

Railroad Construction : Copyright, 1«95, by THE Colliery Engineer Company

Track Work : Copyright, 1896, by THE Colliery Engineer Company.

Railroad Structures : Copyright, 1896, by THE Coluery Engineer Company.

Plate, Platting Angles— I : Copyright, 1896, 1897, 1898, by The Colliery Engineer
Company.

Plate, Platting Angles— II : Copyright, 1895, 1898, by THE COLLIERY ENGINEER
Company.

Plate, Map of Railroad Location : Copyright, 1895, 1898, by THE COLLIERY ENGI-
NEER COMPANY.

Plate, Contours and Slopes: Copyright, 1895, 1898, by THE Collieky Engineer
Company.

Plate, Topogrraphical Maps: Copyright, 1895, 1898, by THE Colliery Engineer

COMPANY.

Plate, Map of Village: Copyright, 1895, 1898, by The Colliery Engineer Com-
pany.



All rights reserved.



BURR printing HOUSE,

FRANKFORT AND JACOB STREETS,

NEW YORK.



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^

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CONTENTS.



Surveying. page

Geometrical Principles, 601

Compass Surveying, - - -. 605

Transit Surveying, 621

Triangulation, 634

Curves, 639

Leveling, 655

Topographical Surveying, 673

Indirect Leveling, 682

Hydrographic Surveying, 690

Land Surveying.

United States System, 693

Areas, 714

Latitudes and Departures, - - - . . 717

Town Sites and Subdivisions, - . , . 733

Mapping.

Introduction, . - 741

Platting Angles, - - .- 741, 748

Map of Railroad Location, 766

Topographical Drawing, - - • , . 776

Contours and Slopes, - *-,,- 779

Conventional Signs, - - - . - - 789

Topographical Maps, 792

Map of Village, * - - 799

Railroad Location.

Introduction, 813

Reconnaissance, 815



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iv CONTENTS.

Railroad Location — continued, page

Field Work, - - - - - - - - 823

Problems in Location, 832

Specifications for Grading and Bridging, - - 860

Railroad Construction*

The Engineer Corps, - - - - 869

Cross-Sectioning, ..;-.. 870

Culverts, 878

Retaining Walls, 809

Excavation, - • 912

Tunnel Work, 935

Protection Work, 966

Routine Work, 970

Bridge Work, 978

Pile Work, 1002

Estimates, 1017

Track Work.

Track Laying, ' .- - 1029

Track Joints, 1036

Rails, 1038

Expansion and Contraction, . . - . 1043

Spiking Rails, - 1045

Surfacing Track, 1048

Drainage, 1052

Care and Maintenance of Track, - - - 1058

Curved Track, 1087

Frogs and Switches, 1102

Yards and Terminals, 1145

General Instructions, - . . _ . 1148

Railroad Structures.

Wooden'Trestles, 1163

Framed Bents, 1177

Floor System, - - 1186

Bracing, - - 1195

Iron Details, 1198



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CONTENTS. V

Railroad Structures — continued.

Connection of Trestle with Embankment — Pro- page

tection Against Accidents, - - • - - 1207

Field Engineering and Erecting, - - - 1211

Specifications for Wooden Trestles, - - - 1213

Bills of Materials, Records, and Maintenance, - 1224

Standard Trestle Plans, 1230

Simple Wooden Truss Bridges, ... - 124G

Water Stations, - - 1274

Coaling Stations, - - 1281

Turntables, . - - ^ . - - . 1285



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SURVEYING.




GEOMETRY.

1 180. If two triangles have two sides and the included
angle of the one equal to two sides and the included angle
of the other, the triangles are ^
equal in all their parts. Thus,
in the two triangles ABC
and D E F, Fig. 236, if the
side ^ ^ is equal to the side
D E ; the side B C to the side J" ^ £-
£F, and the angle B to the • fig.«86.

angle E, the triangles are equal in every respect.

1181. If a straight line, A By Fig. 237, intersects two
parallel straight lines, C D and E F, it is called a secant

with respect to them, and the eight
angles formed about the points of in-
tersection have different names applied
to them with respect to each other, as
follows:

First — Interior angles on the

same side are those which lie on the

Pio. 287. same side of the secant and within the

other two lines. Thus, in Fig. 237, H G D and G H F are

interior angles on the same side.

Second — Exterior angles on tbe same side are those
which lie on the same side of the secant but without the
other two lines. Thus, A G D and F H B are exterior
angles on the same side.

Third — Alternate Interior angles are those which lie
on opposite sides of the secant and within the other two
lines. Thus, C G //"and G H F2ltq alternate interior angles.

For notice of the copyright, see page immediately following the title page.




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Fourth — Alternate exterior angles are those which
lie on opposite sides of the secant and without the other two
lines. Thus, A G C and F H Bvive. alternate exterior angles.

Fifth — Opposite exterior and Interior angles are

those which lie on the same side of the secant, the one within
and the other without the other two lines. Thus, A G D
and G H F are opposite exterior and interior angles.

1182* If a straight line intersects two parallel lines,
the sum of the interior angles on the same side is equal to
two right angles, and the sum of the exterior angles on the
same side is also equal to two right angles. Thus, in Fig.
237, the interior angles D G H and F H G are together
equal to two right angles, and the exterior angles D G A
and F H B are together equal to two right angles.

1183* If a line intersects two parallel straight lines,
the alternate interior angles are equal to each other, and
the alternate exterior angles are also equal to each other.
Thus, in Fig. 237, the angle C G H is equal to F H G, and
angle C G A is equal to F // B,

1184* The complement of an angle is the difference

A £ between that angle and a right angle.

/ Thus, in Fig. 238, A B E is the comple-

/ ment oi D B E,

(

D 1185. The supplement of an

Fio. 288. angle is the difference between that

angle and two right angles. Thus, C B E is the supplement

oiDB E,

1 186. In any triangle, a line drawn
parallel to one of the sides divides the
other sides proportionally. Thus, in the
triangle ABC, Fig. 239, the line D E
drawn parallel to B C divides the sides
A B and A C proportionally ; that is,
- A B : A D:: A C : A E ;
A D : DB :: A E : E C, and
A B : D B :: A C : E C. iic^^ao.



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SURVEYING. 603

1187. Polygons are similar when they are mutually
equiangular and have their homologous sides proportional.

In similar polygons, any points, lines, or angles similarly
situated in each are called tiomolosous. The ratio of a
side of one polygon to its homologous side in another is
called -the ratio of similitude of the polygons.

1188* Triangles which are mutually equiangular are
similar, and their areas are to each other as the squares of
their homologous sides.

Thus, in the triangles
A B C2LndD E F, Fig. 240,
if the angle A is equal to the
angle D\ the angle B to the
angle £", and the angle C to
the angle /% the triangles are fig. 840.

similar, and their areas are to each other as the squares of
their homologous sides.

For example, if B C=%0 feet, £ F=60 feet, and the
area of the triangle A B C = 1^600 sq. ft., then
80' : 50' :: 1,600 : area oi D E F, or
6,400 : 2,500 :: 1,600 : 625 sq. ft.
Hence, area oi D E Fis 625 sq. ft.

1189* The areas of similar polygons are to each other
as the squares of their homologous sides.

Thus, if the area of a regular hexagon with a side of 10
inches is 259.809 sq. in., the area of a similar hexagon whose
side is 15 inches may be found as follows:

10* : 15' :: 259.809 : area required, or
100 : 225 :: 259.809 : 584.57 sq. in.

1190* The circumferences of circles are to each other
as their diameters, and their areas are to each other as the
squares of their diameters.

Thus, if the circumference of a circle 12 inches in diam-
eter is 37.7 inches, the circumference of a circle of 18 inches
diameter may be found by proportion. Thus,

12 : 18 :: 37.7 : 56.55 in., the circumference required.



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— B



Again, if the area of a circle of 12 inches diameter is
113.098 sq. in., the area of a circle of 18 inches diameter
may be found as follows:

12* : 18' :: 113.098 : area required, or
144 : 324 :: 113.098 : 254.47 sq. in.
1191« An angle formed by a tangent and a chord
meeting at the point of contact is
measured by half the included arc.

Thus, in Fig. 241, the angle A C D
formed by the meeting of the tangent
A B and the chord C D is measured
by half the arc C E D. Similarly, the
angle B C D is measured by half the
Fio. 841. arc C D,

1192* Two tangents to a circle drawn from any point
are equal, and if a chord be drawn joining
these tangent points, the angles between
the chord and the tangents are equal.

Thus, in Fig. 242, the two tangents
A B and A C drawn to the circle from
the point A are equal, and the angles
ABC and A C B, formed by the chord
and tangents, are equal to each other.

1193* In the same or equal circles
equal chords subtend equal angles at the
center and also at the circumference. fig. s42.

Thus, in Fig. 243, the angles A O B, B O C, and COD
subtended by the equal chords A B,
B C, and C D are equal to each
other.

Again, the angles B A C and
CAD are also equal to each
other.

1194. In Fig, 244, X^t A B C

be any triangle. If one of the

sides, as A C, is prolonged, the

Fig. 24S. angle BCD included between the





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SURVEYING. 605

side thus prolonged and the other side B C oi the triangle,
which meets A C at C is called an
exterior an^le. The two remain-
ing angles A and B of the triangle,
which are opposite to the angle C,
are called opposite interior
alleles. In any triangle, an ex-
terior angle is equal to the sum of
the two opposite interior angles; that
is, in the above figure, the exterior angle B C D is equal to
the sum of the two opposite interior angles, A and B.

1 195. Problem. — Having given one of the angles of a
triangle, one of the including sides, and the difference of
^ the other two sides, to construct

it.

Let Cy Fig. 245, be the given

angle, A the given side, and B

the difference of the other sides.

Draw D E equal to the given

side A\ Sit D make the angle

E D F equal to the given angle C\

Fio. »«. on D F lay oR D G equal to the

given difference B. Join E G. At the middle point If of

£ G erect a perpendicular cutting D Fin K, Draw AT E.

D E K\s the required triangle.




COMPASS SURVEYING.

1196. Tlie Compass. — The surveyor's compass

consists of the magnetic needle, the case in which it is en-
closed, and the support on which it is placed when ready for
use.

1197. Tlie Magnetic Needle. — The masnetie

needle is a slender bar of steel, five or six inches in length,
strongly magnetized, and mounted upon a finely pointed
pivot on which it freely turns, always pointing in the same



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606



SURVEYING.



direction, viz. : the north and south line, or, as it is called,
the magnetic mcrldan.

11 98. Nortti and Soutli Ends of Needle. — Owing

to the earth's attraction, the north end of the needle dips,

that is, it is drawn downward from a horizontal position,

while the south end is correspondingly raised. To prevent

this dipping, several coils of platinum wire are wound

„, ,. „,. around the south end

y-Platinutn Wire, ,. , ,, , t^.

— -^ 1 'iV of the needle (see Fig.

J^FivoL 246), keeping it per-

fectly balanced upon
Pio. 246. its pivot and permit-

ting entire freedom of movement. These coils of wire at
once indicate to the observer which is the north end and
which is the south end of the needle.

1199. The Sights. — At either end of a line passing
through the needle pivot is a slstit, which consists of an
upright bar of brass A and B. (See Fig. 247.) Narrow




Fig. a47



vertical slits, with holes at their top and bottom, divide this
bar, as shown at C and D. These arrangements enable
the observer to train the line ot sight upon any desired
object.



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SURVEYING.



607



1 200. The Divided Circle. — The compass box con-
tains a graduated circle divided to half degrees, at the
center of which is the pivot supporting the needle. The
degrees are numbered from 0° to 90° both ways from the
points where a line drawn through the slits would cut the
circle.

1201. Lrettering. — The lettering of the . surveyor's
compass is at first confusing to those learning its use. A
person standing with his back to the south and facing the
north will have the east on his right hand and the west
on his left. These latter directions, viz., the east and
the west, are reversed in the lettering of the compass.
The reasons for this apparent error are explained in the
following figures :





Fig. 248.



Fig. 2i9.



Suppose the needle and compass are pointing due north
and south in the direction of the line A B, as shown in
Fig. 248, and the line of survey changes its direction 45° to
the right, or east. The magnetic needle will remain motion-
less, while the sights and the circle to which they are fast-
ened will move until the sights point in the direction C D,
Fig. 249, and, as the north end of the compass is ahead, the
needle will read N 45° E, which is the true direetion being
run. If, however, the east and west points of the compass
were the actual magnetic directions, i. e., the right hand
east and the left hand west, the direction of the line C D



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608 SURVEYING.

would have read N 45° W, which would be the reverse of
the actual direction.

1202« Lrevels. — On the compass plate are two small
spirit levels F and G, (See Fig. 247.) They consist of
glass tubes, curved slightly upwards and nearly filled
with alcohol, leaving a small bubble of air in them. One
of these tubes, F^ is in the line of sight, the other, G",
is at right angles to it. Their object is to enable the
observer to place the compass in a perfectly horizontal
position. This is done by so moving the compass as
to bring the air bubbles to the centers of the tubes. To
prove these bubbles to be in adjustment, proceed as fol-
lows: Having brought the bubbles to the centers of the
tubes, revolve the compass through 180° or one-half of
an entire revolution. If the bubbles remain in the cen-
ters of the tubes, they are in adjustment. If they do
not so remain, bring them half way back to the middle
of the tubes by means of small screws attached to the
tubes, and the remainder of the way by moving the plate
in the ordinary way, repeating the operation until the
bubbles remain in the center of the tubes in every position
of the compass.

1 203« The Tripod. — The compass is usually supported
by a single standard, shod with steel, and called a Jacob's
Staff. A more perfect support, called a tripod, consists
of three legs shod with steel and connected at the top so as
to move freely. Both Jacob's Staff and tripod are connected
with the compass by means of a ball and socket joint, which
permits free movement in all directions.

1204« Defects of the Compass. — The compass is
not intended for work requiring great accuracy. The direc-
tion to which the needle points can not be read with pre-
cision, and the perfect freedom of movement of the needle
may be prevented by local attraction or by particles of dust
adhering to the pivot. An inaccuracy of one-quarter of a
degree in reading an angle, i. e., the amount of change in



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SURVEYING. 609

the direction of two lines, will cause them to separate from
each other If feet in a distance of 400 feet.

Suppose the line A B, Fig. 250, is due east and west, and
the line B C, which is an actual boundary, has a true direc-
tion of N 85° E, and suppose the surveyor reads the
directions ^ C as N 84° 45' E. Let B C = 400 feet, then,
the point C, when mapped, will take the position C\ which is
1 J feet to the left of C where it should be. Another defect
of the compass lies in the fact that the magnetic needle does



Fig. 250.

not always point in the same direction. This direction some-
times changes between sunrise and noon to the amount of
one-quarter of a degree. Frequently its direction is changed
by /oca/ influence. A piece of iron on the surface of the
ground or a mass of iron ore beneath are frequent disturbing
influences.

1 205. Taking: Bearings. — The bearing: of a line is
the angle which it makes with the direction of the magnetic
needle. By the course of a line we mean its 'length and its
bearing taken together. To take the bearing of a line, set
the compass directly over a point of it, at one extremity, if
possible. This may be done by means of a plumb bob sus-
pended from the compass, or, if the compass be mounted on
a Jacob's Staff, by firmly planting the staff directly on the
line. Then, by means of the air bubbles, bring the compass
to a perfectly level position. Let a flagman hold a rod care-
fully plumbed at another point of the line, preferably the
other extremity of it, if he can be distinctly seen. Direct
the sights upon this rod and as near the bottom of it as pos-
sible. Always keep the same end of the compass ahead;
the north end is preferable, as it is readily distinguished by
some conspicuous mark, usually a ''' fleur de /is,'' and always
read the same end of the needle, that is, the north end
of the needle if the north point of the compass is ahead.



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610 SURVEYING.

and vice versa. Before reading the angle, see that the eye
is in the direct line of the needle so as to avoid error
which would otherwise result from parallax, or apparent
change of the position of the needle, due to looking at it
obliquely.

The angle is read and recorded by noting, first^ whether
the N OT S point of the compass is nearest the end of the
j^ needle being read; second, the
/ number of degrees to which it
points, and third, the letter E or
W nearest the end of the needle
being read.

Let A B, in Fig. 251, be the
direction of the magnetic needle,
B being at the north end. Let
the sights of the compass be
directed along the line C D. The
north point of the compass will be
seen to be nearest the north end
of the needle which is to be read. The needle which
has remained stationary while the sights were being
turned to C D, now points to 45"^ between the N and E
points, and the angle is read north forty-five degrees east
(N45^E).

1 206« Backslstits. — A sure test of the accuracy of a
bearing is to set up the compass at the other end of the line,
1. e., the end first sighted to, and sight to a rod set up at the
starting point. This process is called backslstitliifi:. If
the second bearing is the same as the first, the reading is
correct. If it is not the same, it shows that there is some
disturbing influence at either one or the other end of the
line. To determine which of these two bearings is the true
one, the compass must be set up at one or more intermediate
points, when two or more similar bearings will prove the true
one. When a line can not be prolonged by magnetic bearings,
on account of local attraction, the true direction is maintained
by backsighting.




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SURVEYING.



611



1 207. Declination of the Needle. — ^The masnetie
meridian is the direction 6f the magnetic needle. The true
meridian is a true north and south line, which,
if produced, would pass through the poles of the
earth. The declination of the needle is the
angle which the magnetic meridian and the true
meridian make with each other.

In Fig. 252, let N S he the true meridian for
any given place, and N' 5* the magnetic meridian.
The angle NA N^ is the declination of the needle
for that place.

1 208. The Polar Star. — There is a star in
the northern hemisphere known as the North Star
or Polaris. It is the extreme star in the row or
line of stars forming what is commonly called the ^
handle of the ** Little Dipper." This star very
nearly coincides with the true north point or p**'-
pole, being removed only 1^° from it. It revolves about the
true pole, and twice in each revolution it is exactly in the true

meridian ; that is, in a vertical plane passing
through the true pole P, See Fig. 253. One
may know when the North Star is in the true
meridian from the position of another star.
This other star is in the handle of the ** Big
Dipper, "or Ursa Major, the one nearest the
bowl of the dipper, and is called Alioth. When the North
Star is in the true meridian, Alioth will be found directly
below it.




O



PIO. 968.



TO DETERMINE A TRUE MERIDIAN.

1209. By Observations of ttie North Star.— The
time at which the North Star passes the meridian above the



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