Section 4 Road Contour Question

[Dylan Wilson]

This is from the Shake and Bake test for Section 4. Hopefully it is ok that I post this one question, but I've been struggling to understand contour placement on the road compared to the included diagram. I have the right contours selected and them going in the right direction, but my placement was completely different compared to the answer Shake and Bake has. Could anyone explain this to me or where I can look to learn more on how to understand this question? Thanks!

[Joshua Burwell]

Ill give it a shot. 

The road is concrete so a tangential profile will be had thus the straight lined contour lines.

The road profile is basically like a mountain, with a peak and then two ridges sloping down in both directions down the road from the peak.  contour signature of a ridge are always the contours pointing downhill.

does that help?

[Dylan Wilson]

I guess what I'm confused about is where they placed their proposed contour lines. Their proposed ones don't appear to be connecting to any of the existing contour lines. Is it only important for me to pick out the right direction of contour and place it on the right side? If that is the case then I got it right. I attached what I drew compared to the right answer.

[Solecita Wong]

Hi Dylan, first you need to look at the profile and find the elevations 89, 90, 91, then project the spot down to the plan to find the corresponding elevations and then place the contours (see attached). Hope this helps.

[Dylan Wilson]

This does help! Thanks!

[Ray Freeman]

Joshua, the concrete generates straight lines vs asphalt generate curved lines is ridiculous. This has been promoted for years in some review courses and is just unreliably wrong.

Based on the profile, using the method Solecita outlined is the right approach. She did not mention that the point of the contour which represents the crown at the centerline is used to position the contour correctly.

I think the real problem is that the proposed contours are not labelled which is pretty confusing. specially given that the plan shows a lot of cutting. And there is no tie back to existing contours, which also confuses people.