Quiz #24

[cogborn84]

Thanks for the question! I know a lot of these posts and quizzes are old, but I am going through them since I have finished six min solutions, PE Review tests (not the course just some tests someone gave me), Goswami practice, and Mansour practice. I have studied quite a bit, but I am always looking for more problems to do and these quizzes hit the spot.

I feel like this type of question will be the kind that "gets" me on the exam. I have been preparing well and can handle quite a few "solving" type problems. But the "look-up" type questions could cover a broad range of things that might be a bit tricky.

 

[ngmakhlo_PE]

@cogborn84 you'd be surprised, I felt the same way but now after practicing and studying for months the questions that require looking up factors just jump right out! Good luck! I am in the same boat!

 

[John QPE]

Thanks for the question! I know a lot of these posts and quizzes are old, but I am going through them since I have finished six min solutions, PE Review tests (not the course just some tests someone gave me), Goswami practice, and Mansour practice. I have studied quite a bit, but I am always looking for more problems to do and these quizzes hit the spot.

I feel like this type of question will be the kind that "gets" me on the exam. I have been preparing well and can handle quite a few "solving" type problems. But the "look-up" type questions could cover a broad range of things that might be a bit tricky.

When I took the exam I didn't touch my calculator 50% of the problems. Even less in the AM .... you need to know your references.

 

[JGipe1]

I got 114.24 also. So round up to 115.

Looked up the radius in my EET binder chart (from AASHTO) and then used the spacing equation.

God EET makes things so much easier. I'm going to laugh if I don't use any of my other references besides the conversion chart in the CERM. But I'm sure I will probably have to.

 

[cogborn84]

When I took the exam I didn't touch my calculator 50% of the problems. Even less in the AM .... you need to know your references.

Sheesh, that is quite a large percentage. I had a co-worker mention how surprised he was at the amount of "word" type problems. I would be fine getting to know my references better, however, the only way I know how to get to "know" my reference material is working problems. There really aren't a ton of practice word problems out there, but I have found quite a few on this board that require me to search through some reference material which helps a lot. 

I am also at a slight disadvantage because I worked in the oil field for 3 years with site design and dirt roads. So following AASHTO standards is somewhat new to me other than what I did in school. Luckily I have an excellent memory so most of it came back easily and doing problems has helped me thumb through the books enough that I should be pretty familiar with them.

 

[wannacape]

I have a question. When you determine the minimum radius in first step don't you need both super elevation and friction?

I am looking at the green book formula R(min)= V^2/15(e+f)

what friction value are you using and why?

 

[ptatohed]

I have a question. When you determine the minimum radius in first step don't you need both super elevation and friction?

I am looking at the green book formula R(min)= V^2/15(e+f)

what friction value are you using and why?

I think you can use GDHS eqn 3-7.  f = V^2 / 15R - .01e

You can also use Fig 3-6 to get the assumed side friction factor, f, for design speed 60mph  (f = .12)

Or, you can use Table 3-7 for V = 60 and e = 4%  (f = .12)  You can also read your R right from the table (1500 ft) 

Also, eqn 3-8 (the one you mentioned) is a variation of eqn 3-7, just rearranged. 

 

[wannacape]

I think you can use GDHS eqn 3-7.  f = V^2 / 15R - .01e

You can also use Fig 3-6 to get the assumed side friction factor, f, for design speed 60mph  (f = .12)

Or, you can use Table 3-7 for V = 60 and e = 4%  (f = .12)  You can also read your R right from the table (1500 ft) 

Also, eqn 3-8 (the one you mentioned) is a variation of eqn 3-7, just rearranged. 

Awesome. I found the figure which shows the friction f to assume for a given design speed V. I didn't know that figure was there. THANKS!