Course Title: Engineering Surveying (CVE 301) Course Lecturer: Engr. F. M. Alayaki Civil Engineering Department, College of Engineering, University of Agriculture Abeokuta, Nigeria Course Unit: 3 Contact Time: 2 Hours Laboratory Time: 3 Hours

Course Content Location and setting out of works; roads, bridges, railways, tunnels, pipelines, buildings. Setting out of simple, compound and reverse curves. Sectioning; longitudinal and cross profiles. Calculation of areas and volumes from contours, spot heights and cross-sections. Curvature correction in earthwork measurements. Chain surveying, compass surveying methods. Contours and their uses. Traversing methods. Application of leveling, Geodetic leveling, errors and their adjustment. Application of tachometry.

INTRODUCTION Surveying is a mathematical science used to determine and delineate the form, extent, and position of features on or beneath the surface of the earth for control purposes—that is, for aligning land and construction boundaries, and for providing checks of construction dimensions. Land boundaries are set or measured for proper descriptions; the topography of landforms and natural or artificial objects are depicted on maps. The measurements of a survey are linear or angular, and principles of geometry and trigonometry are usually applied.

Geometry: Geometry is a branch of mathematics that deals with shapes and sizes. Basic geometry allows us to determine properties such as the areas and perimeters of two-dimensional shapes and the surface areas and volumes of three-dimensional shapes.

Trigonometry: Trigonometry is a branch of mathematics that deals with the relationships between the sides and angles of triangles and with the properties and applications of the trigonometric functions of angles. The two branches of trigonometry are plane trigonometry, which deals with figures lying wholly in a single plane, and spherical trigonometry, which deals with triangles that are sections of the surface of a sphere.

SURVEYING INSTRUMENTS Horizontal linear measurements are made with calibrated rules or tapes and sometimes by electronically timing the travel of light or radio waves between points. Vertical linear measurements are made with a graduated vertical rod to find differences of elevation and heights above sea level. The engineer's level, a tripod-mounted telescope equipped with a spirit bubble and a cross wire, is used to sight the graduations on the rod. The horizontal or vertical angles are measured by a transit or theodolite, a tripod-mounted telescope with cross wires, the graduated circles of which indicate angles in degrees, minutes, and seconds.

Electronic distance-measuring devices are being perfected and can give extremely accurate results, up to 1 in 6 million or better. Under development also are electronic angle- measuring devices of great precision.

TYPES OF SURVEYING Plane Surveying Plane surveys treat any small segment of land or water as a horizontal plane. Such surveys are customarily projected and calculated on a horizontal rectangular grid, oriented north-south and east-west, although the grid can be oriented in an arbitrary, rather than true, north-south direction. Geodetic Surveying Geodetic surveys are used for large areas where the basic shape of the earth (the geoid) is taken into consideration. These surveys are based on a spheroidal shape approximating the geoidal or geographic (nearly spherical) shape of the earth at sea level. Land Surveying Land surveying is the determination of boundaries, form (topography) and size of an area by means of observations and measurements.

Topographic Surveying This is undertaken to provide the relative vertical and horizontal measurements of physical features e.g. rivers, roads, streams, etc. Photogrammetry Surveying Much topographic mapping is done by means of aerial photogrammetry, which uses stereoscopic pairs of photographs taken from aircraft and, more recently, from artificial earth satellites. These photos are then reconstituted into stereo models for drafting true-scale maps. Engineering And Construction Surveying Engineering surveys establish control points by traverse, baseline, or other methods to obtain information required for engineering designs and to set out construction from design drawings by use of these control points. Topographic surveys, and the maps produced by them, provide horizontal location information and elevations needed for the design of structures such as buildings, dams, canals, highways, bridges, transmission lines, and sewers.

Cartographic Surveying And Cartography Surveys to set control points and to obtain detail for map and chart making are called cartographic surveys. Charts and maps of a small scale (covering large areas) are compilations of larger-scale maps with much detail omitted. Coastal charts depict the shoreline, but show only significant navigation aids along the shorelines and indicate water depths. Air-navigation charts show only significant geographical features, obstructions, air lanes, radio beacons, and guidance features such as railways and highways. Hydrographic Surveying This is undertaken to provide special information for construction projects sited in water. The surveying and mapping of sea, river, harbor, or lake bottoms to ensure safe navigation depths are done by hand soundings located by observations to or from control points on shore. Mining Surveys Mining surveying is used to establish surface location and boundaries of mining claims.

Typical Questions 1.(a)Explain the term levelling? State the equipment used for levelling State the uses of levelling (b) The following consecutive readings were taken with a dumpy level along a chain line at a common interval of 15m. The first reading was at a chainage of 165m where the reduced level is The instrument was shifted after the fourth and ninth readings , 2.245, 1.125, 0.860, 3.125, 2.760, 1.835, 1.470, 1.965, 1.225, 2.390, and m. Find the reduced level of all the points by rise and fall system. ( c)Plot the profile of your results. 2.Describe fully the following operations as related to surveying practices. i.Land surveying ii.Geodetic surveying iii.Plane surveying iv.Photogrammetry surveying v.Hydrographic surveying

3.(i) Discuss the conditions for carrying out chain-surveying operations and indicate the sources of error in the operations. (ii) Describe with a sketch how you will measure distance on sloping ground and the correction you will apply. 4.(a) What is a contour line. (b) Discuss the two main methods of contouring. ( c) State the difference between a plan and a map. 5.(i) Why is it neither practicable nor desirable for highways and railways to have straight alignment ? (ii) Using neat sketches, discuss four types of horizontal curves. 6.(i) Explain the steps you will take to justify that a Dumpy level with a tag “UNAAB/CVE/02A” is in a good working condition. (ii) Explain why superelevation is required in roads and railways.