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# Slope staking on exam

Posted by bill93 on February 21, 2023 at 12:44 amIn a recent thread this practice exam was mentioned, and I downloaded the Preview file.

https://account.ncees.org/exam-prep/437

I’m trying to figure out question 7, without having any experience doing this. I can follow the math, but have no clue how to figure out the situation.

-I’m thinking this is on raw land and the road finish grade is to be achieved, not existing. True? I don’t think the road is built and now they are trying to get the ditches right.

-If this is right, it seems odd that the HI is almost 9 and a half feet above the target road elevation and even further above the existing ground at the road location. Where did they find a high spot to put the level? That made me think it was to be a cut.

-So how do you know this is in fill?

-The wording of the answer is very confusing. “The test point (road edge) is above the ground by 2.64 ft.” Isn’t the “test point” where you put the rod on the ground, which is below the target road elevation? “Road edge

**is**” (not “to be”) sounds like the road exists. So did I get the situation wrong from the start?-Why would the slopes as given be flatter for fill than for cut?

mathteacher replied 1 year, 1 month ago 15 Members · 40 Replies- 40 Replies

The HI is high probably because the level is setup uphill somewhere. The rod is at 107.67. Design el of 110.31 minus 107.67 is down 2.64 therefore you are in a fill. 28.5 offset minus 12 is 16.5 divided by 2.64 is 1:6.25 therefore the rod needs to move towards centerline about 6 feet. I think that’s what they mean by in but that is a bit ambiguous in my opinion.

Easy to see with a picture

110.31-107.67 = 2.64

2.64/0.25 = 10.56′ from road to ground @ 4:1

12.0+10.56 = 22.56 o/s for toe of slope

28.5 (rod o/s) -22.56 = 5.94′ to move closer to centerline to find toe

Yeah, everybody is giving me the numbers, like the sample answer. I filled in the diagram after seeing that it was fill. No problem. The numbers are easy once the problem is understood.

What I’m looking for is an explanation of the thinking that goes on before you crank the numbers, for someone who is stupid, confused by their wording, and has never done slope staking.

.Yeah, everybody is giving me the numbers, like the sample answer. I filled in the diagram after seeing that it was fill. No problem. The numbers are easy once the problem is understood.

What I’m looking for is an explanation of the thinking that goes on before you crank the numbers, for someone who is stupid, confused by their wording, and has never done slope staking.

the natural ground is probably sloping. The task is to find the intersection of the 4:1 slope with the ground through trial and error. The Rodman pulls the tape from centerline to his guess where the intersection is. For purposes of the next trial shot assume the ground is flat, so move in 6 feet and try again. Maybe it’s still less than 4:1 so try again but the question is asking for an estimate of the move in distance for the next try.

you guys are causing a little anxiety here….just kidding. I’m glad the question on ” how do you approach the question” are being asked because they definitely leave room for over thinking and confidence in grasping one item but not fully grasping the whole.

whew. glad I’m past this and beginning to aim at the next one.

to be sure, make sure you check the updates to the test prep questions, they had to correct about 4 I think recently because they didn’t have the correct answer selected. no I’m not kidding.

Use the old formula to intersect the two grades. (the existing ground determined by two shots and the proposed slope).

Old is the key word here, and I really do not understand why these examinations focus on ancient knowledge. Do you want your employees to be proficient in ancient techniques, and sacrifice productivity.

The concept of slope staking, and correct me if I’m wrong, is to stake the point at which a proposed grade meets existing grade. We called it the daylight line in one of my classes. That is most easily understood if the cross section is a cut and the side slope is rising out of cut to “daylight” at the existing ground.

It is a simple task with a computer model. It can also be translated by means of an alignment, profile, and cross section template in the field computer.

Since it is a trial and error process, a reading from the prism pole will translate to a cut or fill in the field computer. Once the cut or fill is zero you have achieved the daylight line. There are no stakes on the slope. The stakes are placed at the top or bottom of the slope. Is that correct?

Reliance on hand calculated methods would make the chance of errors greater that the reliance on a computer process.

Historic Boundaries and Conservation EffortsAhh, the old slope staking days.

Things change fast in surveying.

From the old days of a Brunton, right angle prism, tapes, 3 man crews to today with no stakes, no crews just some machine doing it all.

Can’t say I miss it.

Even the local small guy is doing one of our subdivisions all on his own, totally machine control.

I say have at it!!!!

Use the old formula to intersect the two grades. (the existing ground determined by two shots and the proposed slope).

Formulas?

We did it all in our heads, I was younger then but we usually shouted out numbers while the PC was poking his calculator. By the time he had the catch point figured out we had the stake in the ground and marked up as he told us what to write on the lath. Already picking up and shifting to the next station. Slope staking is a feel thing after a while, some people instinctively get it and some just don’t catch on. Of course, digging and filling were really helpful.

I only ever set slope stakes one time and I used a total station with data collector with the cross section template set in it, that was at least 25 years ago. so yes the question is like asking an automotive tech how to put a steel band on a wooden wagon wheel. The one project I did involved 15 to 20′ high cut banks, to do that with a level would’ve been a lot more difficult. I don’t remember the fill side as much.

-Why would the slopes as given be flatter for fill than for cut?

Very common engineering principle. Fill slopes are always flatter than cut slopes. I’m not certain of the reasoning, but I was told that a 6:1 fill slope is about the maximum a runaway car can handle without flipping, while cut slopes are generally limited by the angle of repose of the material.

I think that this is an excellent problem from several perspectives.

1) The student has to know whether the test point is above or below the roadbed. In the field that would be obvious, but working backwards from the numbers reinforces the relationship between the numbers and the terrain.

2) The student has to know whether he needs to move the rod closer to or further away from the instrument. This is a fundamental judgement that comes up in many real-world applications. It is a physical problem very much related to whether one value is greater or less than another, something that is sometimes very hard to teach in mathematics.

3) In addition to direction of movement, the student has to determine how far to move.

As to modern vs ancient methodology, we read frequent complaints about button-pushers. The old methods were derived directly from physical and mathematical concepts; the newer ones are one or more iterations away from those.

For a test, it could have been made easier by asking only one question like are you above or below the roadbed.

But who would vote for easy exams?

Slope staking for me today is usually a pad, but the principle is the same with a road, dam, pad. For a pad site there will be a fill and a cut side along with two grade points. Normally I have the topo data for the pad design so in theory with a perfect topo I could pre calculate all the catches and stake them. I do know of many who “do” that or try to do that. The problem is the accuracy of the underlying topo data which is never perfect on raw ground. So it’s better to calculate the catches in the field, and I believe much quicker.

I will walk around the pad with the catch line inserted into the data collector and if the cut is 3:1, I find the point by wondering 12′ from the cut line with a 4′ cut and stake the point. It’s not like the old days where the station controls the position. Let the station float and catch the even foot points. Basically, you fly through the process. And the dozer guy loves even foot catches, he doesn’t care about stations. Same with the fill side usually a 4:1, find the point 16′ out with a 4′ fill, simple. The GPS drags you right to that point.

I like hard tests. I felt like I had no chance in passing the FS, and did. I don’t give myself enough credit for being abke to problem solve, but then again we are usually our own worst and most painful critic.

and I suck at typing, more so on a little itsy bitsy phone..

Yes, but the technology eliminates items 1) and 2) from what’s needed to solve Problem 7. An apprentice learns only how to use GPS to find a stake point, the rest of the understandng is lost.

If an apprentice knew how to solve Problem 7, how hard would it be to teach (mentor) him on using the GPS procedure? On the other hand, if he knew the GPS procedure, would there be any value in his knowing the concepts involved in the older method? How hard would the mentoring be? Personally, I would rather teach GPS to someone who understands Problem 7 than the other way around.

I first started teaching Geometry after the advent of standardized end of course testing. Shockingly, my experienced colleagues did not require proofs in their courses; proofs weren’t required on the multiple choice exam.

But proofs are essential to understanding why the principles used in surveying and many, many other fields always work. Understanding proofs makes the exam easy.

The further we get from the fundamental relationships, the lower the level of understanding becomes.

Very true Math Teacher, GPS is the dummying down of surveying. The first day I got my RTK system it was so simple. Look I can do this, I can run line, slope stake, calculate areas, ect.

Nothing to any of it.

GPS is really an easy to use tool for surveying.

The surveyor needed to have much more skill and knowledge in the transit/tape fieldbook era.

For us, it was a competition to see who could get the answer first and a check to make sure the first guy got it right…

It’s been a long time!

I hope everyone has a great day; I know I will!Indeed. Surveyor education faces the same challenges in our rapidly expanding technological world as other fields. Consider, for example, the potential impact of ChatGPT on thesis writing.

We old guys in every field had to learn techniques that were very close to the fundamental principles underlying whatever problem we were trying to solve. NASA had rooms full of human calculators as did NGS. No need for them now, but somebody has to know the principles to write the software and to verify results.

Surveying education cannot possibly keep up with surveying technology. To me, that means that education should focus on basic principles and hiring entities should provide the procedures training. After all, everybody’s procedures are d8ffernt. How in the world can educators teach them all?

Yes, it takes time and money to develop competent employees and yes, they will leave if there are better opportunities. The alternative, though, is continuing to put up with button pushers and the havoc they can wreak.

For us, it was a competition to see who could get the answer first and a check to make sure the first guy got it right…

It’s been a long time!

Staking some of the large slope staking jobs like large railroad cuts we would use a brunton for slope chaining and we could slope reduce it. There is a chart on the back of the so we would do it in our heads, good times.

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