CECC481 Highway Terms and Surveying Terms

Asphalt

it is a dark brown to black cement-like material in which the predominant constituents are bitumen that occurs naturally or is obtained through petroleum processing.

Base

the top surface of a road structure. It is also the component of the road structure which receives the traffic laod and transfers it to the subgrade.

Base coat

it is a plaster coat or coats applied prior to application of the finish coat.

Collector Street

is a type of street which serves internal traffic movements within an area and connects this area with major arterials.

Expressway

a divided arterial highway for through traffic with full or partial control of access and generally with grade separation at intersections.

Freeway

is an expressway with full control access

Hardness

the hardness of asphalt cement is obtained by conducting a penetration test

Highway

a general term denoting a public way for purposes of vehicular travel, including the entire area within the right of way.

Interchange

is a system of interconnecting roadways in conjunction with one or more highway separations providing for the interchange of traffic between two or more intersecting highways, usually without at-grade crossing of through and major turning movements.

Intersection

is an area/section where two or more roads come together.

Overpass

when the major highway is taken above by raising its profile above the general ground level by embankment and an overbridge across another highway.

Pavement

is the layered structure placed over a soil sub-grade for forming a road.

Prime coat

is the single application of liquid bituminous material to a previously prepared and untreated road base, such as earth, gravel, stabilized soil, or water-bound macadam base courses.

Road bed

– is the graded portion of a highway within the top and side slopes, prepared as a foundation for the pavement structures and shoulders

Seal coat

a very thin surface treatment of bituminous material which is applied as a final step in the construction of certain bituminous wearing surfaces of roads.

Sub-base

– is the part of the road structure which is immediately above the subgrade and composed of stone boulders or superior soil.

Subgrade

is the layer of natural soil over which the pavement of a road is laid

Tack coat

– is the single initial application of bituminous material to an existing bituminous, Portland cement concrete, or block surface or based.

Underpass

when the major highway is taken by depressing it below the ground level to cross another road by means of an underbridge.

Wearing course

is the layer in a road pavement which provides resistance to wear and tear due to traffic.

Contour lines

is an imaginary level line that connects points of equal elevation. This is also the most common method of representing the topography of an area.

Foresight reading

- is taken on a rod held on a point whose elevation is to be determined.

Form lines

are used in the maps intended for purposes of navigation to show peaks and hilltops along the cost lines. Form lines resemble contours, but are not drawn with the same degree of accuracy.

Hachures

are a series of short lines drawn in the direction of the slope. It gives a general impression of the configuration of the ground, but they do not give the actual elevations of the ground surface.

Height of the Instrument

In stadia surveying, it is required to determine the elevation of the line of sight.

Pace

is defined as the length of a step in walking. It may be measured from heel to heel or from toe to toe.

Pacing

consists of counting the number of steps or paces in a required distance.

Photogrammetry

– is the science of mapping out a big tract of land and consist in taking overlapping photographs from airplane flown at adequate altitudes.

Planimeter

An instrument or device used to determine the area of any irregular figure plotted on a map that is drawn to scale.

Saddle

refers to a geographical feature where two adjacent hilltops or ridges slope downward on both sides, creating a low point or dip between them. This low point resembles the shape of a saddle, hence the term.

Stadia Method

provides a rapid means of determining distances. The equipment for stadia measurement consists of a telescope with two horizontal hairs called stadia hairs and a graduated rod called a stadia rod.

Tachymetry (or tacheometry)

is another procedure of obtaining horizontal distances. It is based on the optical geometry of the instruments employed and is an indirect method of measurement.

Taping

is the method of measuring or laying out horizontal distances by stretching a calibrated tape between two points and reading the distance indicated on the tape.

Thalwegs

It refers to the line of lowest elevation within a valley or watercourse, which typically represents the path of a river or stream's current.

Transit rule

is the correction to be applied to the latitude or departure of any course is to be the total error of latitude or departure as the length of the course is to the length of the traverse is one way of balancing a traverse.

Zenith

a point where the vertical produce upward, pierces the celestial sphere.