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The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals - Leaving Cert DCG - Question C-1 - 2018
Question C-1
The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals. (a) On the drawing supplied, draw a vertical se... show full transcript
Worked Solution & Example Answer:The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals - Leaving Cert DCG - Question C-1 - 2018
Step 1
On the drawing supplied, draw a vertical section (profile) on the line AB.
Answer
- Measure the heights at each contour line on the map at intervals of 5 meters.
- Draw horizontal lines at each of these heights on a vertical axis.
- Project points from the contour lines at the intersections with line AB.
- Use these projections to outline the terrain profile on the drawing, ensuring to illustrate the changes in elevation accurately.
Step 2
A vertical pylon is to be built at point A. On the profile, determine the minimum height of the pylon, if its top is to be visible from the ground at point B.
Answer
- Identify the line of sight from point B to point A on the profile.
- Draw a tangent line from point B to the profile at point A.
- Measure the height at which this line intersects the vertical axis to determine the minimum required height for the pylon.
Step 3
Using side slopes of 1:1 for the cuttings and 1:2 for the embankments, complete the earthworks on the northern side, which are necessary to accommodate the roadway.
Answer
- From the centerline CD at 25 meters, draw parallel lines at 5-meter intervals to designate cutting locations.
- Identify key points of elevation on these cutting curves.
- Draw the cutting curves connecting these points smoothly.
- Repeat the process for embankment areas, using a slope of 1:2 and denoting elevations at 10-meter intervals.
- Identify points on the embankment curve and draw it connecting these key points.