Class Objectives CE 211 SURVEYING ENGINEERING CLASS 09: LEVELING (3) 9/12/2011 VERTICAL CONTROL (BENCHMARK) SURVEYS

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CE 211 SURVEYING ENGINEERING CLASS 09: LEVELING (3) Ahmed Abdel-Rahim, Ph.D, P.E. Associate Professor,

Benchmark Leveling and Field Notes Field Procedure Checking for Mistakes Error of Closure and Precise

1 CE 211 SURVEYING ENGINEERING CLASS 09: LEVELING (3) Ahmed Abdel-Rahim, Ph.D, P.E. Associate Professor, Civil Engineering Class Objectives Identify benchmark leveling procedures Develop field notes for benchmark leveling and computation and adjust benchmark elevations Identify profile leveling procedures Develop field notes for profile leveling and computation and adjust benchmark elevations. Benchmark Leveling and Field Notes Field Procedure Checking for Mistakes Error of Closure and Precise Leveling Precise Leveling Benchmark Monuments Adjusting Benchmark Elevations FIGURE (a) Plan of benchmark leveling. 1

FIGURE 5-21. (Continued) (b) Side view of the benchmark leveling run in (a). FIGURE 5-21. (Continued) (c) Form of field notes used with benchmark leveling. FIGURE 5-22. (a) Level set up too low.

2 FIGURE (Continued) (b) Side view of the benchmark leveling run in (a). FIGURE (Continued) (c) Form of field notes used with benchmark leveling. FIGURE (a) Level set up too low. (b) Level set up too high. Example-1 A differential leveling loop began and closed on BM Bridge (elevation m). Readings (in meters) listed in the order taken are (BS) on BM Bridge, (FS) and (BS) on TP1, (FS) and (BS) on BM X, (FS) and (BS) on TP2, and (FS) on BM Bridge. Prepare, check, and adjust the notes. 2

Example-1 Example -2 A leve1ing circuit began on BM Hydrant (elevation 85.35 ft) and closed on BM Rock (elevation 96.17 ft). Readings (in feet) given in the order taken are 2.65 (BS) on BM Hydrant, 3.

Example 2 Example 3 A differential leveling circuit began on BM Rock (elevation 543.202 m) and closed on BM Manhole (elevation 545.551 m). Readings (in meters) listed in the order taken are 1.

3 Example-1 Example -2 A leve1ing circuit began on BM Hydrant (elevation ft) and closed on BM Rock (elevation ft). Readings (in feet) given in the order taken are 2.65 (BS) on BM Hydrant, 3.51 (FS) and 7.23 (BS) on TPl, 5.04 (FS) and (BS) on BM 1, 8.58 (FS) and 7.65 (BS) on BM 2, 4.23 (FS) and 7.53 (BS) on TP2, and 4.34 (FS) on BM Rock. Prepare, check, and adjust the notes. Example 2 Example 3 A differential leveling circuit began on BM Rock (elevation m) and closed on BM Manhole (elevation m). Readings (in meters) listed in the order taken are (BS) on BM Rock, (FS) and (BS) on TPl, (FS) and (BS) on BM 1, (FS) and (BS) on BM 2, (FS) and (BS) on TP2, and (FS) on BM Manhole. Prepare, check, and adjust the notes. 3

total length of 900 m had a misclosure of 0.

4 Example 3 Table 5-1. Accuracy Standards for Vertical Control Surveys Example -4 Example -4 A leveling loop with a total length of 900 m had a misclosure of m, what order of leveling is represented A leveling loop with a total length of 900 m had a misclosure of m, what order of leveling is represented Order of leveling: C= 12mm 0.90 = 11.4 mm Meets third order 4

FIGURE 5-23. A precise level with parallel plate micrometer enables vertical displacement to be measured to 0.1 mm. An accuracy of + or - 0.2 mm in 1 km of leveling (;0.001 ft/ml) can be obtained.

5 FIGURE A precise level with parallel plate micrometer enables vertical displacement to be measured to 0.1 mm. An accuracy of + or mm in 1 km of leveling (;0.001 ft/ml) can be obtained. (Courtesy of The Lietz Company.) FIGURE Illustration for Example 5-1. Table 5-2. Adjusting (Closing) a Line of Benchmark Elevations Profile leveling is one of the most common applications of running levels and vertical distance measurement for the surveyor. The results are plotted in the form of a profile, which is a drawing that shows a vertical section or side view of the earth s surface. Profiles are required for the design and construction of roads, curbs, sidewalks, storm drainage systems, water supply or sewer pipelines, and many other types of public infrastructure. 5

6 Field Procedure Plotting the Profile Cross-Section Leveling FIGURE Profile leveling; several rod shots are taken from each instrument position FIGURE (a) Top view showing the route centerline and the line for crosssection leveling at station (b) The cross section, showing ground elevations at points left and right of the centerline. FIGURE Example of profile-leveling field notes. 6

Example Below are rod readings in the order in which they were taken. The elevation of the starting benchmark is listed at the top of the column. The last reading is taken on the starting benchmark.

7 Example Below are rod readings in the order in which they were taken. The elevation of the starting benchmark is listed at the top of the column. The last reading is taken on the starting benchmark. Put into proper field note form, include arithmetic check. If the B.S. & F.S. distances are 150 feet, what is the order of accuracy? Balance the bench run error FIGURE Cross-section field notes. Example Reduce and plot at a scale of 1 =200 horizontal and 1 =20 vertical, the following set of profile notes. 7

CHAPTER 01 Basics of Surveying

CHAPTER 01 Basics of Surveying 1.1 How do plane surveys and geodetic surveys differ? Plane surveying assumes all horizontal measurements are taken on a single plane and all vertical measurements are relative