Transcript Islamic University of Gaza Civil Engineering Department Surveying II

Islamic University of Gaza
Civil Engineering Department
Surveying II
ECIV 2332
By
Belal Almassri
Chapter 9
Route Surveying – Part 1
Definitions.
- Horizontal and Vertical alignment.
- Types of Horizontal Curves.
- Simple Circular curve geometry.
- Terminology and Formulas.
-
Route Surveying
-
Route Surveying is the branch of surveying
that performs the survey works (mapping
and setting out) of routes (highways,
railways..etc).
-
Route surveying is comprised of all survey
operations required for design and
construction of engineering works such as
highways, pipelines, canals, or railroads.
- Design of Routes includes:
1. Horizontal Alignment.
2. Vertical Alignment.
-
-
Horizontal Alignment: consists of
straight lines (tangents) and horizontal
curves.
Vertical Alignment: consists of straight
lines (gradients) and vertical curves.
Types of Horizontal Curves:
- A. Circular Curves:
1. Simple Circular
2. Compound Circular.
3. Reverse Circular.
4. Spiral Circular.
5. Broken Back Circular.
Broken Back
Notes on the Circular Curves:
1. The broken back type is being used
inside the town on the other hand
the reversed type is being used
outside the town.
2. In the broken back type, if the
distance between A and B is greater
than 30 meters then each one of
them is called simple.
3. For safety reasons the reversed type
should be avoided as possible.

B.Transitional Curves:
- A mathematically calculated curve on a
section of highway, or railroad track, where a
straight section changes into a curve. It is
designed to prevent sudden changes
in centripetal force.
- F = mv²/r
F: centripetal force.
m, v: mass and velocity.
r: radius.
It start with radius equals infinity (straight line)
so the F value will be zero and then the r is
going smaller and smaller.

Simple Horizontal Circular Curve
Geometry
R, RADIUS: The radius of the circle
where the radius is always
perpendicular to back and forward
tangents.
PC, POINT OF CURVATURE: The point of
curvature is the point on the back tangent
where the circular curve begins.
PT,POINT OF TANGENCY: is
the point on the forward tangent
where the curve ends.
PI, POINT OF INTERSECTION: The intersection
of the back and forward tangents.
L, LENGTH OF CURVE: The length of curve is
the distance from the PC to the PT, measured
along the curve.
T, TANGENT DISTANCE: The tangent distance is
the distance along the tangents from the PI to
the PC or the PT.
E, EXTERNAL DISTANCE: The distance between
the PI to the mid of the curve.
LC,LONG CHORD: The long chord is the
straight-line distance from the PC to
the PT.
Δ, CENTRAL ANGLE: The angle between two
radii of circle.
M, MIDDLE COORDINATE: The distance from
the midpoint of the curve to the midpoint
of the long chord.
- All of the formulas in terms of R and Δ ,
where R is known and Δ can be measured
from the field.
Quiz