Fieldwork 4(Final)

8/10/2019 Fieldwork 4(Final)

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Mapua Institute of Technology

ADVANCED SURVEYING FIELD MANUAL

FIELDWORK NO. 4

Laying of a Simple Curve on Uneven Ground Using

Transit and Theodolite

(Double-Deflection Angle Method)


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GROUP NO. 4 CHIEF OF PARTY/LEADER: EUGENIO, Jason

MEMBERS:

DULAY, Anthony Mark V. GARCIA, Julienne

ESTAVILLO, Kyle GATCHALIAN, Kenneth

FIELD WORK NO.3

LAYING OF A SIMPLE CURVE ON UNEVEN GROUND USING TRANSIT

AND THEODOLITE (DOUBLE-DEFLECTION ANGLE METHOD)

OBJECTIVE:

1. To be able to lay a simple curve on uneven ground.

2. To be able to lay a simple curve using double-deflection angle method.

3. To master the use of the transit and theodolite in laying a simple curve.

INSTRUMENTS:


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PROCEDURE:

1. The Professor gives the following data:

d1 = 0.11

D = 2.5

d2 = 1.39

Location of PC on the site (Note location and not station is now given since d1and d2are

given.)

GIVEN: I=d1+6D+d2= (Simple curve with 6 intermediate points.)

NOTE: Be very careful in assigning the location of PC and the direction of the backward tangent

so that the curve will not obstructed by any structure.

VERY IMPORTANT: Before going to the field the student must compute:a. Angle of Intersection I = 49

b. Total deflection angle I / 2 = 24.5

c. Length of the long chord C = 380.16

d. Half d1 d1/ 2 = 0.055

e. Half d2 d2/ 2 = 0.695

f. Half D D / 2 = 1.25


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2.4Loosen the upper clamp and turn the telescope until the reading on vernier equals the

magnitude of the total deflection angle of the curve. Along this line and with a distance

equal to the length of the long chord from PC locate the position of PT.

2.5Set the theodolite on the exact position of PT.

2.6Level the theodolite and set the horizontal vernier to zero while sighting PC.

3. To locate the first intermediate point A in the curve mark on the ground the intersection of theline of sight in both instruments with a reading equal to

.(Note that the first instruments

reading is referred from the back tangent while the second instruments reading is referred

from the long chord.)

4. The next intermediate point B may be located on the ground using the same procedure as in

step 8, but this time use a reading equal to (d

.

5. The third intermediate point C may also be found following the same processes, but now use a

reading in the horizontal vernier equal to (d

.

6 Continue the process to locate other intermediate points on the curve with a gradual increase


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FINAL DATA SHEET

FIELD WORK 3 LAYING OF A SIMPLE CURVE ON UNEVEN GROUND USINGF THEODOLITE

(DOUBLE-DEFLECTION ANGLE METHOD)

DATE: 11/05/14 GROUP NO.: 5

TIME: 02:00 PM LOCATION: MIT South Parking

WEATHER: Cloudy PROFESSOR: Engr. B.Cervantes

DATA SUPPLIED:

d1 = 0.11

D = 2.5

d2 = 1.39

Adopt full chord length of 2 m

GIVEN:

I = d1 + 8D + d2 = 21.5

a. Angle of intersection I = 49b. Total deflection angle I/2 = 24.5c. Length of long chord C = 380.16d. Half d1 d1/2 = 0.055


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SAMPLE COMPUTATION

Given:

d1 = 0.11D = 2.5d2 =1.39

Angle of intersection, I = 49Length of long chord, C =380.16d2/2 =0.695

D =1.25

Solution:

Intersection Angle, I:

I = d1 + 8D + d2 = 21.5

Total Deflection Angle, I/2

I/2 = 49/2

I = 24.5

Long Chord, C:

C = 2 * R * sin (I/2)

C = 2 * 458.37 * sin (49/2)

C = 380.16

First Intermediate Point, A

A = d1/2

A = 0.11/2

A = 0.055

Second Intermediate Point, B

B = [(d1+D)/2]

B = [(0.11+2.5)/2]

B = 1.305

Third Intermediate Point, C (Until 20th Intermediate

Point)

C [(d1+2D)/2]

At Intermediate Point A

Computed Length of the Chord = 0.88


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Analysis of Data

In the first part of this fieldwork, we were to lay a simple curve

on uneven ground, to lay a simple curve using double-deflection

angle method and to master the use of the transit and theodolite in

laying a simple curve.

From the gathered data taken from the said activity, it can be

seen that every detail gathered was tallied in the given data. The

summation of deflection angles taken was all equal to 35 which are

half of the given angle of point of intersection which is 70 degrees.

And also the chord distances were all equal to 280 meters and so

close to the length of the main curve.

Conclusion

In performing this fieldwork which deals with laying of a

simple curve on uneven ground using transit and theodolite using


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Acknowledgement

Firstly, I would like to thank God for giving me another day

to do what I have continued and another day to prove myself and do

all the tasks that life has given me. And also for all the people he

has given me to love, to care and to make my life more joyful.

Including my parents, friends, professors, acquaintances, and even

those people who make my life thrilling.

Also, I would like to thank my group mates for their effort

and their time and also their cooperation in participating in this

fieldwork. Also, I would like to mention about doing their assigned

tasks and doing it right in order for us to finish the field work on

time.

Lastly, I would like to show my gratitude to my professor,

Engr. Cervantes, for teaching us and guiding us for our activity and

for imparting his ideas regarding the topic and make it possible for

us to do it on our own. And at the end of the day, there was another


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station with vernier A set at zero. The telescope is then reversed by

plunging it. A foresight to the next station is then taken by turning

the instrument about the vertical axis on its upper motion, and thedeflection angle is observed. The angle is recorded as right R or left

L, according to whether the upper motion is turned clockwise or

counter clockwise. Usually, deflection angles are observed twice,

once with the telescope in face left and the other in face right

condition. Immediately after completion of traverse observation, an

arithmetical check on the angular error of closure should be

performed to detect any blunder or excessively large error in angular

measurement.

To check the angular closure, azimuths are calculated from

previously known azimuth of a line. The unknown azimuth of a line

is computed by adding the right deflection angle and subtracting the

left deflection angle with the forward azimuth of the previous line.

Thus,


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azimuth or on the observed deflection angles.

In the azimuth adjustment method, the computed azimuth

of the closing line is compared with its previously observed value. If

both the values agrees each other, there is no error of closure

otherwise it exist. To remove the error, a correction equal in

magnitude but opposite in nature to the error of closure is to be

distributed among the observed deflection angles.

In the deflection angle adjustment method, the algebraic

sum of the deflection angles is being computed taking the right

deflection angles as positive and left deflection angles as negative.

The general relation to compute the error of closure by this method

is as follows:

Forward azimuth of the first side of traverse (at first

station) + -

traverse (at terminating station) + 360---- (Equation 28-1)


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A deflection angle should never be measured without double

centering the instrument, because the error caused by the line of

sight not being normal to the horizontal axis of the instrument may

be too large to be tolerated. Moreover, the angular error of closure

should not exceed the estimated standard deviation for observing an

angle from a single setup times the square root of the number of

instrument stations. In practice, this estimated standard deviation in

angular measurement is usually taken equal to 0.5 to 1.0 times the

least count of the instrument used in measuring the angles. If the

error exceeds the permissible limit, then observation should be

repeated till permissible limit has been achieved.

Deflection angle method of traversing is being generally used

for open looped closed traverse. It is most useful for the location

survey of linear engineering works such as highways, railways,

canals and pipelines etc.


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DOCUMENTATION

Everyone is looking for a space to

lay a simple curve

I t di t i t ith l


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XI. Field Work Peer Assessment

Course: CE1211F Section: B1 Date: November 12, 2014

FIELDWORK 4:LAYING OF A SIMPLE CURVE ON UNEVEN GROUND BY TRANSIT AND THEODOLITE

(Double-Deflection Angle Method)

Group Members:ESTAVILLO, Kyle Score: 20

EUGENIO, Jason Score: 20GARCIA, Julienne Score: 20GATCHALIAN, Kenneth Score: 20

CRITERIA EXCELLENT VERY GOOD LIMITED POOR MEMBERS

TIME ELEMENT Arrives exactly ontime.

Arrives within the

grace period of 15

minutes

Late for at most

30 minutes

Late for more than 30

minutes

4 4 4 4

PREPAREDNESS Knows what exactlyis to be done in thefield

Familiar with the

procedure

Needs further

explanation

Does not know what is

to be done

4 4 4 4

COOPERATIVENESS Performs assignedtask willingly and iswilling to help

group mates

Performs only

assigned task

Performs less

satisfactory the

assigned task

Does not want to help

at all

4 4 4 4

ACCURACY Computes for therequired valueaccurately and insuch a short time

Computes for the

required value with

little assistance

Computes for

the required

value with some

assistance

Fails to compute the

required value

4 4 4 4

OVERALL

CONTRIBUTION ON

THE GROUPWORK

Performs an

important role

efficiently

Performs an

important role

Performs a

secondary role

in a limited

manner

Does nothing 4 4 4 4


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Fieldwork 4(Final)