Indiana LICA Contractor Certification Training Workshop

Indiana LICA Contractor Indiana LICA Contractor Certification Training Certification Training

WorkshopWorkshop

20082008

Basic Surveying ConceptsBasic Surveying Concepts

Basic Surveying ConceptsBasic Surveying Concepts►What you need to know to perform correct What you need to know to perform correct

construction and checkout of NRCS practicesconstruction and checkout of NRCS practices Ability to work with benchmarks that do not Ability to work with benchmarks that do not

have elevations of 100.00have elevations of 100.00 Ability to work with both rod readings and Ability to work with both rod readings and

elevationselevations Ability to use the slope equationAbility to use the slope equation Ability to establish your own benchmarks and Ability to establish your own benchmarks and

turn pointsturn points Ability to perform a bench level circuitAbility to perform a bench level circuit


►Benchmarks with elevations not 100.00Benchmarks with elevations not 100.00 NRCS is using GPS survey grade equipment to NRCS is using GPS survey grade equipment to

survey more and more practices as we progresssurvey more and more practices as we progress

Survey Grade GPS will not be using an elevation Survey Grade GPS will not be using an elevation of 100.00 for benchmarks most of the timeof 100.00 for benchmarks most of the time

The concept is the same regardless of the The concept is the same regardless of the elevation of the benchmarkelevation of the benchmark


►Waterway ScenarioWaterway Scenario


►With surveys based on benchmarks With surveys based on benchmarks with Elevation of 100.00with Elevation of 100.00 1. You set up your laser (on zero grade!) 1. You set up your laser (on zero grade!)

and take a shot (Back Sight- BS) on the and take a shot (Back Sight- BS) on the benchmarkbenchmark

2. You add that rod reading to 100.00 to 2. You add that rod reading to 100.00 to get the height of the instrument (HI)get the height of the instrument (HI)

3. Then to obtain elevations you subtract 3. Then to obtain elevations you subtract your next rod readings (Fore Sights – FS) your next rod readings (Fore Sights – FS) from the HIfrom the HI

Basic Surveying ConceptsBasic Surveying Concepts►When you use a benchmark of a different When you use a benchmark of a different

elevation, it’s the same processelevation, it’s the same process

Basic Surveying ConceptsBasic Surveying Concepts► Obtaining elevations from HI (HI – FS = Elevation)Obtaining elevations from HI (HI – FS = Elevation)

► Ground shots and their Ground shots and their elevations are rounded elevations are rounded to tenths (0.X’) of a footto tenths (0.X’) of a foot


►Normally when you set up you can not Normally when you set up you can not see the entire project from that one see the entire project from that one set-upset-up

In these cases, you have to perform what In these cases, you have to perform what is called a turnis called a turn


►Performing a turn requires:Performing a turn requires: A solid Turn Point that will not move while A solid Turn Point that will not move while

surveyingsurveying A Fore Sight on the Turn Point to determine A Fore Sight on the Turn Point to determine

its elevation from HIits elevation from HI Move the instrument to a new locationMove the instrument to a new location Take a Back Sight on the Turning Point to Take a Back Sight on the Turning Point to

determine the new HIdetermine the new HI Continue surveying/ checkoutContinue surveying/ checkout

Taking a FS Shot on the Turn Point Taking a FS Shot on the Turn Point (TP)(TP)

► Shots on “hard” objects can Shots on “hard” objects can be recorded as hundredths be recorded as hundredths (0.XX’) of a foot(0.XX’) of a foot

► All Benchmark shots and turn All Benchmark shots and turn points should be this waypoints should be this way


Even hundredths are at the top of the black marks (0.02, 0.04, 0.06, 0.08)

Odd hundredths are at the bottom of the black marks (0.01, 0.03, 0.05, 0.07, 0.09)

3.86

3.82 3.75

3.97


-Taking a Back Sight (BS) on the Turn Point (TP)

-Since we know the TP elevation from the previous Fore Sight (FS), we take a BS on the TP to obtain the new HI


With a new HI established, you can continue taking checkout shots which are all Fore Sights (FS)


If you can shoot the original TBM from your second set-up do so and make sure your TBM elevation checks out as the same elevation from when you started.


► If you can’t see the original benchmark If you can’t see the original benchmark or the instrument is too high for you to or the instrument is too high for you to shoot it, you’ll have to make another shoot it, you’ll have to make another turn back to complete your checkout turn back to complete your checkout notes.notes.

►This has to be done to verify the math This has to be done to verify the math of all your shots. of all your shots.

►This is also how you can check to see if This is also how you can check to see if our TBM’s are correct… in case you are our TBM’s are correct… in case you are having trouble with them.having trouble with them.


►When you begin with a benchmark and When you begin with a benchmark and checkout your project and complete one checkout your project and complete one or more turns and then turn back into or more turns and then turn back into the benchmark to check yourself, you the benchmark to check yourself, you have completed a bench level circuit.have completed a bench level circuit.

►Your project checkout shots (waterway Your project checkout shots (waterway grade, bottom width, etc.) really aren’t grade, bottom width, etc.) really aren’t part of the circuit as they don’t verify part of the circuit as they don’t verify the shots taken on the benchmarks and the shots taken on the benchmarks and turn points.turn points.


► The Slope EquationThe Slope Equation Slope = Change in Elevation/ Change in DistanceSlope = Change in Elevation/ Change in Distance

► ExampleExample The elevation at station 11+00 is 564.3 and the The elevation at station 11+00 is 564.3 and the

elevation at 12+50 is 565.5 elevation at 12+50 is 565.5 ►The change in elevation is (565.5 – 564.3 = 1.2’)The change in elevation is (565.5 – 564.3 = 1.2’)►The change in distance is (12+50 – 11+00 = 150’)The change in distance is (12+50 – 11+00 = 150’)►Slope = 1.2’/150’ = 0.008 which is 0.8%Slope = 1.2’/150’ = 0.008 which is 0.8%►This means that for every 100’ the constructed grade This means that for every 100’ the constructed grade

goes up or down 0.8’goes up or down 0.8’

Documents

Indiana LICA Contractor Certification Training Workshop