CE1202: Introduction to Infrastructure Planning - Study Notes

Instructor: Dr. T.M. Rengarasu

Surveying: The science of determining the position, in three dimensions, of natural and man-made features on or beneath the surface of the Earth.
- Importance: Essential to engineers for planning, designing, and constructing projects.
- Engineers must understand:
- Limits of accuracy in construction and manufacturing processes.
- Capabilities and limits of surveying instrumentation and techniques.
- This combined knowledge helps in completing projects economically and efficiently.

Two primary functions:
1. Produce a plan or map.
2. Lay out pegs or marks on the ground.

Control: A framework of survey stations with precisely determined coordinates.
Economy of Accuracy: Surveys should be as accurate as necessary for specific purposes without excess accuracy.
Consistency: Modern survey adjustment methods allow flexibility; not all parts of a survey need to have the same quality.

Independent Check: A technique to guard against blunders or gross errors; applicable at all survey stages.
Safeguarding: Ensures protection of work; requires legible and unambiguous documentation, particularly for control surveys and survey monuments.

Surveys to produce maps or plans showing main physical features on the ground like roads, rivers, and buildings.
Map scale considerations:
- 1:10,000 or smaller = map
- Greater than 1:10,000 = plan

Surveys for producing plans showing property boundaries and areas for land tax assessment.
Accuracy is crucial to prevent disputes over land.

Surveys conducted specifically for engineering purposes (buildings, dams, roads).
Usually limited in area and treated as plane surveys.

Hydrographic Surveying: Studies areas of water (e.g., lakes, rivers) for shorelines and underwater features.
Underground Surveying: Conducted within mines and tunnels for layout and planning purposes.

Example Scales:
- 1:10,000 scale indicates that one unit on the map represents 10,000 units on the ground.
- 1:200 scale indicates one unit on the map represents 200 ground units.
Allowable scales for surveys: 1:100, 1:200, 1:250, 1:500, 1:1000.

Reconnaissance Survey
- Includes walkover survey and reference sketch (prospection diagram).
- Identify potential problems and solutions.
- Determine the optimal control network with minimum control points.
Marking and Fixing Stations
- Include the use of wooden pegs in soft ground for control networks.
- Ensure they are distinguishable for progress monitoring.
Running the Survey Line
- Implement practical surveying principles.

Characteristics:
- Usually painted with alternating red-white or black-white bands.
- Wooden poles may have metal tips for reinforcement.

Considerations:
- Avoid tie measurements on the same side to optimize the layout.

Example involving locations such as Ambilipitiya and surroundings.
Includes coordinates and features such as trees and roads relevant to survey plots.

Working from Whole to Part
- Establish a set of precise control points first.
- Minor points can then be accurately defined with less precise methods.
- Prevents error accumulation and magnification.
Locating a Point with Reference to Two Fixed Points
- Relative positions are determined by measurements from two fixed reference points.

Using Two Distances:
- Point C determined by the intersection of arcs from points A and B.
Using Perpendicular Measurements:
- Drop a perpendicular to reference line and measure lengths.
Using Angles:
- Measure an angle and distance from the known point to plot new point.