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FIELD WORK NO. 5DIFFERENTIAL LEVELING WITH AND WITHOUT TURNING POINTS

SUBMITTED BY:SAMARTINO, JOHN MEGRYAN B.CESE-2 / 2013106636GROUP NO. 9

SUBMITTED TO:

ENGR. B. A. CERVANTESELEMENTARY SURVEYING FIELD MANUALFIELD WORK NO. 5DIFFERENTIAL LEVELING WITH AND WITHOUT TURNING POINTS

COURSE AND SECTION: CE120-20F/A2

SUBMITTED BY:NAME: Samartino, John Megryan B. STUDENT NO.2013110517

GROUP NO: 9 CHIEF OF PARTY: Ramos, Jasmine

DATE OF FIELD WORK: 05/12/15 DATE OF SUBMISSION: 05/19/15

SUBMITTED TO:

Engr. B. A. Cervantes

SCORE

TABLE OF CONTENTS

MEMBERS

OBJECTIVES

INSTRUMENTS

PROCEDURES

DATA SHEETS

COMPUTATIONS DISCUSSION

CONCLUSION

RELATED RESEARCH

PICTURES

FIELD WORK PEER ASSESSMENT

GROUP NO. 9 CHIEF OF PARTY: Ramos, JasminMEMBERS:1. Rendon, Emerson

2. Reyes, Leo

3. Rongavilla, Joyce Regine

4. Samartino, John Megryan

FIELD WORK NO. 5DIFFERENTIAL LEVELING WITH AND WITHOUT TURNING POINTSOBJECTIVES:1. To develop the skills in determining the difference in elevation between two points both of which are accessible from a single point of observation using a dumpy level.2. To acquire the knowledge of finding the elevation of a point from a bench mark of known elevation by establishing turning points to and from the point of unknown elevation.3. To develop the technical know-how of using precise level.4. To work harmoniously and effectively with ones group while performing each assigned task.

INSTRUMENTS:1. Precise Level3. Chalk

2.1 leveling rod4. Plumb bob

ORGANIZATION OF PARTY:Chief of Party (COP)1. 1 rod man2. Instrument man3. 1 recorder

PROCEDURE:A. Determination of difference in elevation between two points both of which are accessible from single point of observation.

1. The professor designates the locations of two points A and B which can be observed from a single instrument set-up and of considerable difference in elevation.2. Set-up the level on the suitable point preferably equidistant from the assigned points A and B by driving the tripod firmly on the ground. Adjust the height of the level to be convenient for the instrument man by using the leg screw of the tripod.3. Make sure that the base plate of the level is nearly parallel to the horizon. Center the bubble such that even if the instrument is rotated clockwise or counter clockwise in its base the bubbles remain at the center.4. Take the backsight (BS) of point A where the levelling rod is being held vertical with the aid of a plumb bob. The reading must be done up to an accuracy of a millimetre or thousandths of a meter.5. Rotate the telescope until point B is in sight.6. The rod man must transfer the leveling rod at B and must hold it in a vertical position with the aid of a plumb bob.7. Take the foresight (FS) reading of a leveling rod and again the reading must be done up to an accuracy of a millimetre or thousandths of a meter.8. The difference between these readings will give the difference in elevation between the two points A and B.9. Repeat procedures 2-9 for the second trial. Preferably, another member of the group sets the level at a different point balances the bubble and reads the BS and FS to get the difference in elevation between two points A and B. The mean difference in elevation of the two trials will be recorded as the most probable difference in elevation.

B. Determination of the elevation of a point with the aid of a benchmark of known elevation.

1. The professor designates two points BM-1 and BM-2 (The party may or may not use the same points known as A and B in the above exercise). The elevation of BM-1 or A may be known or may be assigned. In order for the two points not to be observed from a single instrument set-up, if you choose to use the same two points as in exercise A, one must use a different route.2. Set-up the level on the suitable point along the route from BM-1 to BM-2. Adjust the height of the level to suit the height of the instrument man by using the leg screw of the tripod.3. Make sure that the base plate of the level is most nearly parallel to the horizon. Center the bubble such that even if the instrument is rotated clockwise or counter clockwise in its base the bubbles remain at the center.4. Take the backsight (BS) of the BM-1 where the levelling rod is being held vertical with the aid of a plumb bob. The reading must be done up to an accuracy of a millimetre or thousandths of a meter. The BS reading + the elevation of BM-1 gives the height of the instrument (HI).5. Rotate the telescope until the newly established point to be observed from the instrument can be sighted and call it turning point one (TP-1). Take extra care that TP-1 is almost equidistant from the instrument as the BM-1 is from the instrument.6. The rod man must transfer the leveling rod at TP-1 and must hold it in a vertical position with the aid of a plumb bob.7. Take the foresight (FS) reading of a leveling rod and again the reading must be done up to an accuracy of a millimetre or thousandths of a meter. The elevation of this TP-1 is equal to the HI-FS reading.8. Transfer the instrument in another location along the route to BM-2 where the first turning point can be sighted and follow the same procedures as in 2-8 until you reach BM-2.9. One must close the circuit, which means that the same procedure must be accomplished until you reach BM-1 to check immediately its elevation and the accuracy of ones leveling work.COMPUTATIONSThe computation of sample field notes is done in accordance with the steps listed hereunder:A. Computation of the height of the instrumentThe height of the instrument is always equal to the elevation of the point where the back sight is being observed plus the elevation of the point itself.

B. Computation of the height of the instrumentThe elevation of the turning point is always equal to the height of the instrument minus the foresight of the TP observed.

FINAL DATA SHEETFIELD WORK 5DIFFERENTIAL LEVELING WITH AND WITHOUT TURNING POINTS

DATE: May 12, 2015GROUP NO: 9TIME: 7:30 am 12:00 nnLOCATION: Mapua Institute of TechnologyWEATHER: FinePROFESSOR: Engr. Cervantes

A. DIFFERENTIAL LEVELING: WITH TURNING POINT (SINGLE RODED)STATIONBSFSELEVATIONHEIGHTREMARKS

BM #11.45X260251.45Differential levelling started at the east building of MIT

0051.531.35250.15251.68

0101.501.69250.29251.79

0151.471.44250.35251.82

0201.491.37250.45251.94

0251.461.39250.55252.01

0301.431.31250.70252.13

0351.401.45250.68252.08

0401.381.47250.61251.99

0451.391.45250.54251.93

0501.431.46250.47251.90

0551.441.49250.41251.85

0601.451.46250.39251.84

0651.461.48250.36251.82

0701.451.51250.31251.76

0751.471.49250.27251.74

0801.36250.38

DISCUSSIONIn this field work we are tasked by our professor to do differential leveling using the precise level. Differential leveling is the process of measuring vertical distances from a known elevation point to determine elevations of unknown points. Differential leveling uses the vertical distance difference between two points to transfer an elevation from one point to another.

A thorough knowledge of leveling principles and proper application of methods and equipment will prevent costly delays and generate the needed results and accuracy. Here are some techniques to reduce error: Make certain the bubble is centered when you make a rod reading, keep the rod plumb when the reading is taken, establish equal BS and FS reading distances, equal reading distances will cancel out any error caused by the line of sight not being parallel with the axis of the bubble tube on the Dumpy Level, not as important with the self-leveling Automatic Levels and lastly not always possible due to terrain. The most common type of level is an automatic level. It gets its name from an internal compensation system which maintains a horizontal LoS automatically if the instrument is disturbed. The compensation system consists of combinations of fixed and free swinging prisms and mirrors. When the instrument is level the LoS is horizontal. The cross-sectional view shows how the incoming horizontal LoS is reflected and refracted and emerges at the eyepiece in a parallel path.

Although at first glance differential leveling notes may appear a little complicated, they are relatively simple and reflect the leveling process. It is important that running computations be done in the field as data are collected to minimize mistakes. Should a mistake be found, the equipment and crew are able to remeasure immediately. The common mistake of this field work are: Faulty reading of the rod, not fully extending the rod for high readings,t ouching the tripod during reading, And confusion between recording BS and FS entries into the field book. We need to avoid these errors in order to have an accurate measurement.

ConclusionIn this field work, we have achieved the set of objectives that our professor has given us. We developed the skills in determining the difference in elevation between two points both of which are accessible from a single point of observation using a dumpy level by practicing using the precise level. We acquired knowledge of finding the elevation of a point from a bench mark of known elevation by establishing turning points to and from the point which is by studying this field work thoroughly. We develop the technical know-how of using precise level and we worked harmoniously and effectively with ones group while performing each assigned task.Differential leveling is the process of determining relative elevations at various points of interest. The elevations can be tied into a global control system (meters above mean sea level), or referenced to a local benchmark with an assumed elevation.. Differential leveling uses the vertical distance difference between two points to transfer an elevation from one point to another. A backsight (BS) reading is taken on the known point to determine how far above it the Line of Sight is. Adding the BS reading to the point elevation gives the elevation of the instrument (EI). A foresight (FS) reading is taken on the unknown point to determine how far above it the Line of Sight is. Subtracting the FS reading from the instrument elevation gives the point elevation.By learning this technique as a Civil Engineering student will really help me in the future endeavors because in our future works we will surely need this to make our work as surveyors easier and faster. In order to get better results we need to be patient in measuring and aligning the instruments, we carefully look at the measurements in order to have an accurate and precise results. We must enhance our abilities in using this techniques and manipulating the instrument because it will help us in the future.

CONCLUSIONDifferential leveling is the process of measuring vertical distances from a known elevation point to determine elevations of unknown points. Differential leveling uses the vertical distance difference between two points to transfer an elevation from one point to another. Differential surveying is used to determine the difference in elevation between two or more points. It is commonly used to establish the elevation of a benchmark referenced to an existing benchmark. It is also useful for comparing the elevation of several points or objects. Because of this, this type of surveying can also be used in measuring mountains, forests, elevated terrain and finding some significant data about geological studies.

FIELD WORK PEER ASSESSMENTCOURSE: CE120-0FSECTION: A2DATE: 5/19/15FIELD WORK TITLE: DIFFERENTIAL LEVELING WITH AND WITHOUT TURNING POINTSGROUP NO.9GROUP MEMBERS:1. Ramos, Maureen JasminSCORE: 202. Rendon, Emerson SCORE: 203. Reyes, Leo SCORE: 204. Rongavilla, Joyce Regine SCORE: 205. Samartino John Megryan SCORE 20

CRITERIAEXCELLENT 4VERY GOOD 3LIMITED 2POOR 1MEMBERS

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TIME ELEMENTArrives on time.Arrives within the grace of 15 minutes.Late for at most 30 minutes.Late for more than 30 minutes.44444

PREPAREDNESSKnows what exactly is to be done in the fieldFamiliar with the procedure.Needs further explanation.Does not know what is to be done.44444

COOPERATIVENESSPerforms assigned task well and is willing to help groupmates.Performs only assigned task.Limited in performing task.Does not want to help at all.44444

ACCURACYComputes for the required value accurately and in such a short time.Computes for the required value with little assistance.Computes the required value with some assistance. Fails to compute the required value.44444

OVERALL CONTRIBUTION ON THE GROUPWORK Performs efficiently a very important task assigned.Performs the important task assigned.Performs the secondary load assigned.Does nothing.44444

EVALUATORS NAME/SIGNATURE:

PICTURES

Setting-up the precise level and setting the bubbles at the centerIn this picture, one of the group member was determining the measurement using the precise level and recording it.

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