PROBLEMS ON BEARINGS, Basic Civil Engineering

1. PROBLEMS ON BEARING Page 1
QUESTION BANK
PROBLEMS ON BEARINGS
PROBLEMS ON BEARINGS
Types of problems:
Type A) The summation of entire included angle is equal to (2n-4) x 900.
Type B) When the summation of entire included angle is not equal to (2n-4) x 900.
1. Following readings were taken in a closed traverse. Draw a rough traverse showing the included
angles. Calculate the corrected bearings and indicate the stations free from local attraction. Show
specimen calculations. (10 MKS)
Station P Q R S
Line PQ QR RS SP
F.B. 50030’ 140030’ 219000’ 328000’
B.B. 230030’ 319000’ 38000’ 150030’
Soln:
To solve such problem you must know following relations:
 F.B. = Fore Bearing, B.B. = Back Bearing
 F.B. ± B.B. = ± 1800
Step I:
Take the difference of F.B. and B.B. of respective line and check whether the difference is nearly
equal to a1800 or not. (Forget about the Sign).
Eg. 50030’ - 230030’ = 1800
140030’ - 319000’ = 1780 30’
219000’ - 38000’ = 1810
328000’ - 150030’ = 1770 30’

2. PROBLEMS ON BEARING Page 2
Observed
Stn Line F.B. B.B. Difference
P PQ 50030’ 230030’ 1800
Q QR 140030’ 319000’ 1780 30’
R RS 219000’ 38000’ 1810
S SP 328000’ 150030’ 1770 30’
Step II:
Now with the help of F.B. of Every line draw the rough traverse. From the traverse find out I.A.
(included angle) and take the summation of I.A. This summation will match with (2n - 4) x 900.
Observed
Stn Line F.B. B.B. Difference I.A.
P PQ 50030’ 230030’ 1800 1000
Q QR 140030’ 319000’ 1780 30’ 900
R RS 219000’ 38000’ 1810 1000
S SP 328000’ 150030’ 1770 30’ 700
Total 3600
Step III:
Now select such a line whose difference between the F.B. and B.B. is exactly 1800.
For this problem such difference is for the line PQ. That means the difference between 500 30’
and 230030’ is 1800. Therefore write down both reading as it is in the corrected F.B. and B.B.
column.
Now 500 30’ is F.B. at stn P, which is correct F.B. reading. That means the B.B. is also correct at
the same station i.e. 150030’. Therefore write down both reading as it is in the corrected F.B. and
B.B. column.
Now 230030’ is B.B. at stn Q, which is correct B.B. reading. That means the F.B. is also correct
at the same station i.e. 140030’. Therefore write down both reading as it is in the corrected F.B.
and B.B. column.
See the following table which shows the corrected F.B. and B.B. reading.
Observed Corrected
Stn Line F.B. B.B. Difference I.A. F.B. B.B.
P PQ 50030’ 230030’ 1800 1000 50030’ 230030’
Q QR 140030’ 319000’ 1780 30’ 900 140030’
R RS 219000’ 38000’ 1810 1000
S SP 328000’ 150030’ 1770 30’ 700 150030’
Total 3600

3. PROBLEMS ON BEARING Page 3
Step IV:
Now consider the corrected F.B. at stn Q.
Observed Corrected
Stn Line F.B. B.B. Difference I.A. F.B. B.B. Error
P PQ 50030’ 230030’ 1800 1000 50030’ 230030’ Zero at P
Q QR 140030’ 319000’ 1780 30’ 900 140030’ 32000’ Zero at Q
R RS 219000’ 38000’ 1810 1000 220030’ 40030’
S SP 328000’ 150030’ 1770 30’ 700 330030’ 150030’
2. Below are the bearings observed in a traverse conducted with a prismatic compass at a place
where local attraction was suspected?
Line FB BB
PQ 191045’ 1300’
QR 39030’ 2220 30’
RS 22015’ 2000 30’
ST 242045’ 620 45’
TP 330015’ 1470 45’
At what stations do you suspect local attraction? Find the corrected bearings of the lines and also
calculate the included angles. (11)
Solution:
Stn Line observed Difference IA Corrected
IA
Corrected Remark
FB BB FB BB
P
PQ
Q
QR
R
RS
S
ST
T
TP

4. PROBLEMS ON BEARING Page 4
3. The following bearings were taken in running a closed compass traverse: (10)
Station A B C D E
Line AB BC CD DE EA
F.B. 800 10' 1200 20' 1700 50' 2300 10' 3100 20'
B.B. 2590 0' 3010 50' 3500 50' 49° 30' 1300 15'
Compute the interior angles and correct them for observational errors. Assuming the bearing of
line CD is correct. Adjust the bearing of the remaining sides.
Stn Line observed Difference IA Corrected
IA
Corrected Remark
FB BB FB BB
A
B
C
D
E
4. The observed whole circle bearings in a closed traverse ABCD are given below:
Line AB BC CD DA
FB 460 10’ 1190 20’ 1690 30’ 2800 20’
BB 2260 10’ 2980 40’ 3510 10’ 990 20’
Calculate the included angle and apply correction for local attraction and find corrected F.B. and
B.B. Draw a sketch of the traverse. Specimen calculations must be given. (10)
Stn Line observed Difference IA Corrected
IA
Corrected Remark
FB BB FB BB
A
B
C
D
E

5. PROBLEMS ON BEARING Page 5
5. The following bearings were taken in running a closed compass traverse:
Line AB BC CD DA EA
FB 800 10’ 1200 20’ 1700 50’ 2300 10’ 3100 20’
BB 2590 0’ 3010 50’ 3500 50’ 490 30’ 1300 15’
Compute the Included angle and correct them for observational errors. Assuming bearing of the
line CD is correct. Adjust the bearing of the remaining sides.
Stn Line observed Difference IA Corrected
IA
Corrected Remark
FB BB FB BB
A
B
C
D
E
6. Following bearings were taken with a prismatic compass for a closed traverse. Compute the
interior angles and correct them (8)
Line AB BC CD DE EA
F.B. 120°30' 30° 330°30' 260°30' 210°
B.B. 300° 209° 150°30' 80° 310
Stn Line observed Difference IA Corrected
IA
Corrected Remark
FB BB FB BB
A
B
C
D
E

6. PROBLEMS ON BEARING Page 6
7. Following readings are taken in a closed compass traverse. Draw the original traverse. Calculate
the included angles. Check for angular error. Calculate the corrected bearings. Tabulate the
results in tabular form. State the corrections to local attraction of each station. (6)
Station A B C D
F.B. N 10°30’ E N 80° W S 40° W S 80° E
B.B N 81° W S 11° W S 80° E N40030’E
8. Following bearings were observed while running a closed transverse in the
clockwise direction:
Draw a rough traverse. Calculate included angles and check for angular error. Calculate corrected
bearings. Indicate stations free from local attraction and corrections at other stations. (9)
9. Following readings are taken in a closed compass traverse. Draw a rough traverse. Calculate the
induced angles and check for angular error. Calculate the induced angles and check for angular
error. Calculate the corrected bearings. Also indicate the stations free from local attraction
Station A B C D
F.B. N 10°30’ E N 80° W S 40° W S 80° E
B.B N 81° W S 11° W S 80° E N40030’E
10. Following table shows bearings observed for a closed traverse. (9)
Line AB BC CD DA
F.B. 75°30' 19o 45' 289°30' 359°00'
B.B. 260°00' 10°15' 109°30' 176°
Calculate:
i) Included angles of the traverse.
ii) Corrected bearings of each line.
iii) Tabulate the results and draw a neat sketch of the traverse.
Line AB BC CD DA
F.B. N 74° 30' W N 32° E S 31° E S 18°30' W
B.B. S 74° 30' E S 300W N 28°30' W N 18° E

7. PROBLEMS ON BEARING Page 7
11. Below are the bearings observed in a traverse survey conducted with a prismatic compass at a
place where local attraction was suspected?
Line FB BB
PQ 1240 30’ 3040 30,
QR 680 15’ 2460 0’
RS 3100 30’ 1350 15’
SP 2000 15’ 170 45’
At what station do you suspect local attraction? Find the corrected bearings of the lines and also
calculate the IA.
12. The following readings were taken in a closed traverse. Draw a rough traverse. Calculate the
included angle and check for angular error. Calculate the corrected I.A. Also indicate the stations
free from local attraction.
Line AB BC CD DA
FB N66015’E S50015’E S38030’W N53015’W
BB S 640 W N 470 W N 370 30’E S 530 15’E
13. Below are the bearings observed in a traverse conducted with a prismatic compass at a place where
local attraction was suspected? At what stations do you suspect local attraction? Find the corrected
bearings of the lines and also calculate the included angles. (10)
Line F.B. B.B.
PQ 191045’ 13000’
QR 39030’ 2220 30’
RS 22015’ 2000 30’
ST 242045’ 620 45’
TP 330015’ 1470 45’

8. PROBLEMS ON BEARING Page 8
14. The following bearings are the observed bearings of the lines of a traverse ABCDEA with a
compass in a place where local attraction was suspected. Find the included angles and correct
bearings of the lines. (10)
Line F.B B.B
AB 140⁰45' 318⁰15'
BC 216⁰30' 38⁰00'
CD 209⁰15' 30⁰15'
DE 319⁰45' 139⁰45'
EA 60⁰15' 240⁰15'