Preferred Cross sections

I was looking at these two figure in the RDG and was wondering how a question could be asked and ow to effectively answer the question correctly. I could not find a sample question for an example like this, so I made this one up and would like to know if this is even correct.

Questions:

Given a 1:4 (H to V) backslope of 4 ft wide trapezoid ditch, what is the steepest acceptable foreslope for this channel. The answer would be 1:4? My reasoning is that a 1;3 falls out of the shaded area.

I this how this figure should be used?

Roadside Design Guide Chapter 3 11.pdf

You can probably expect a problem where given will be: V, ADT, VPD, roadway lane width, shoulder width and radius and the question will be where can an object such as a pole or tower be placed to meet the clear zone distance requirement.

You will then use Table 3-1 and Table 3-2 to solve the problem.

They will make the problem straight forward but give you lot of info to throw you off track.

Hope this helps and good luck!

305Gurl said:

I was looking at these two figure in the RDG and was wondering how a question could be asked and ow to effectively answer the question correctly. I could not find a sample question for an example like this, so I made this one up and would like to know if this is even correct.

Questions:

Given a 1:4 (H to V) backslope of 4 ft wide trapezoid ditch, what is the steepest acceptable foreslope for this channel. The answer would be 1:4? My reasoning is that a 1;3 falls out of the shaded area.

I this how this figure should be used?

Click to expand...

305, it appears you are still using the 3rd edition RDG and not the 4th. In comparing the 3rd to the 4th, it looks like Figures 3-6 and 3-7 haven't changed (not even the Figure #s) so hopefully you're ok. To answer your question - Yes, given a 1:4 (V to H, not H to V ) backslope w/ a 4' wide ditch bottom, the steepest "preferred" foreslope would be 1:4 - using Fig 3.7.

ptatohed.

I just wanted to stop and give my sincerest gratitude to you for provide assistance to the problems I posted. Ptatohed, you go beyond and above to help out with your hand written notes of solution you posted on this board. The questions I posted on this board and the timely responses helps me to stay focused and it paid off with the sweet "Congratulation Letter".

To everyone else too who helped, sincerest thank you. Hopefully I will be able to chime in whenever I see a problem posted by a future test taker, that I have worked before or know how to solve. This website is invaluable to the engineering profession. Thank you, Thank you and Thank you!!!

Thanks for the kind words 305. And a Big Congrats to you! Good job.