2. CIVIL DEPRTMENT

3.  Introduction :  The process of laying out engineering projects by placing pegs Or marks at the site of works is known as setting out works.  setting out is the process of transferring the distance from the plan already prepared to the ground before starting the construction.

4.  Setting Out A Building :  Setting out of a building involves the transfer of the foundation plan from paper into the actual size.  The object of setting out a building is to provide the builder with clearly define outlines for excavations.

5.  The equipments required for the job are : 1.a 30m steel tape 2. two metallic tapes (15m or 30m) 3. a long cord 4.plum bob 5. Stakes or pegs 6. nails, and 7. a hammer

6.  It is of little use to set the pegs at the exact position of each of the corners of the building as they would be dug out while excavating the foundation.  It is that for advisable to first set out a reference rectangle either out side the limits of the excavation or along the centre lines of the outside walls of the building and then to locate each centre by means of coordinates with reference to the sides of the rectangle.

7.  Setting Out A Building By Circumscribing Rectangle :  PROCEDURE : 1. Preparation of the foundation trench plan showing the width of the foundation for various walls. 2. Temporary pegs are driven at the actual corner points of the foundation plan.

8. 4.A cord is stretched between the pegs P and Q. At P, a line is set out perpendicular to PQ.On this line, the position S is marked by setting a peg. 5. Step 4 is repeated at point Q so as to obtained point R. 3.Then using these pegs as reference, a parallel line say PQ of required length is set out at an arbitrary selected distance (i.e. 2m ) from the actual centre line.

9. 7. Once all the points are staked, a cord is pass around the periphery of the rectangle and the actual excavation lines are marked using lime. 6. Having now set out the reference rectangle PQRS, the actual corners can be marked using the sides of the reference rectangle PQRS.

10. Setting Out A Building By Circumscribing Rectangle : 

11.  Setting Out Building By Centre Line Rectangle :  Procedure: 1. The reference rectangle formed by centre lines of the outside walls of the building as shown in fig. Is known as centre line rectangle. The corners are located by measuring their co-ordinates with reference to the sides of this rectangle. the temporary pegs are fixed at these points.

12. 3. By using these pegs the position of any point can be obtained by plotting its co-ordinates using the reference pegs. In case of precise working i.e. For important buildings, a Theodolite should be used for setting out right angles. Bench marks should be established in convenient positions away from the site of works so that they remain undisturbed until the work is completed. 2. Since these pegs are not permanent and will be lose during excavation, the sides of the centre line rectangle are produced on both the sides and permanent pegs are fixed on each of the prolongations, at of fixed di stance, say 2m, as shown in fig.

13. Setting Out Building By Centre Line Rectangle

14.  Setting Out A Culvert :  A culvert is set out by locating the corners of the abutments and wing walls at the foundation by means of their co ordinates with reference to centre lines of a road and a stream crossed.  The centre lines of road and stream which cross each other are taken as axes of co ordinates, their origin being at the centre of the culvert.  The co ordinates of different points are found from the foundation plan and indicated in the tabular form.

15.  In fig. AB and CD are centre lines of road and stream respectively passing through the centre O of the culvert and co ordinates for the points, 1, 2, 3 etc are

16.  Procedure :  Drive a peg at O and set up the theodolite over it. Fix points P,Q,R,S etc on line AOB by arrows. The cord passing through the eyes of the arrows will defined the line AB.  Set out the line CD right angles to AB and fix the points EFGH, IJKL etc by arrows.  Stretch the cords along lines AB and CD. Set off the distances OP, OQ, OR, OS etc on AB and OE, OF, OG, OH and OI,OJ,OK,OL etc on CD and fix arrows at all these points.

17.  Set out corner 1 by measuring co ordinates x1 and y1 from P and F respectively with the help of two tapes and mark it with a peg.  Similarly fix other points by their co ordinates and drive pegs at each point.  Pass a cord around the periphery of abutment and wing walls as 1, 2, 3, 4, 5, 6, 7, 8, and mark the outline of the foundation with lime and by nicking i.e. Cutting a narrow trench along this line.

18.  Similarly fix the corners of other abutment and wing walls and mark the outline of the foundation.  Take levels at all pegs and determine depth and quantities of excavation.  If the wing walls are curved, the points on the curved may be set out by offsets to the chords 1-8, 6-7 and 2-3, 4-5 as indicated in fig.