250 likes | 808 Views
AIM OF SESSION. To introduce setting out of basic horizontal road curves. SESSION OBJECTIVES. Explain some basic terminology associated with horizontal road curvesIdentify the process for setting out a simple horizontal curveIdentify and derive some of the terms required to calculate the required
E N D
1. BUEUG2027CIVIL ENGINEERING SURVEYING 2 SETTING OUT HORIZONTAL CURVES
2. AIM OF SESSION
3. SESSION OBJECTIVES Explain some basic terminology associated with horizontal road curves
Identify the process for setting out a simple horizontal curve
Identify and derive some of the terms required to calculate the required data for setting out curves
Go through an example to calculate required data
4. Purpose of Circular Curves
6. Calculating Arc Length
10. Example
18. Locate the tangent point and set up the theodolite over it. This is usually done by locating the Intersection Point from the straights and taping back along one straight, or set out directly from control survey points by calculating their co-ordinates.
Sight the IP through the telescope and set the horizontal circle to zero. Alternatively, sight back down the straight and set the horizontal circle to 180°.
Turn the theodolite to the required angle for the entry sub-chord and, with the zero end of the tape attached to the tangent point peg, mark out the position of the first point on the curve.
Turn the theodolite through a further angle corresponding to the deflection angle for the first full short chord and, with the zero end of the tape now attached to the first curve peg, mark out the position of the second point on the curve.
Repeat the process until the second Tangent Point is reached.
Check the curve using a different method, e.g. halving and quartering.
Locate the tangent point and set up the theodolite over it. This is usually done by locating the Intersection Point from the straights and taping back along one straight, or set out directly from control survey points by calculating their co-ordinates.
Sight the IP through the telescope and set the horizontal circle to zero. Alternatively, sight back down the straight and set the horizontal circle to 180°.
Turn the theodolite to the required angle for the entry sub-chord and, with the zero end of the tape attached to the tangent point peg, mark out the position of the first point on the curve.
Turn the theodolite through a further angle corresponding to the deflection angle for the first full short chord and, with the zero end of the tape now attached to the first curve peg, mark out the position of the second point on the curve.
Repeat the process until the second Tangent Point is reached.
Check the curve using a different method, e.g. halving and quartering.
22. Further Reading