Reference no: EM13861890

Question 1

The Level Book extract below shows results of a closed level traverse around a property that picks up levels of the ground and some features around the property boundary.

BS	IS	FS	Rise	Fall	RL	Dist	Notes
2.510						0	BM #234         RL 73.452
	2.260						A.    Peg
	1.990						B.     Peg
3.210		1.420				85m	CP- C. Mark on Access hole
	2.850						D. Peg
	2.400						E. Access hole cover
1.600		1 SO0				159in	CP- F. Peg
	1.450						G. Peg
	1.500						H. Stormwater Inlet
0.720		1.660				230m	CP- I. Peg NW of building
	0.840						J.       Peg
	0.810						K.    Peg
		0.620				276m	BM #74           RL 75.992

a. Complete the Level Book entries and calculate the reduced levels.

b. Determine the level misclose.

c. Determine the maximum allowable misclose for this engineering survey using the formula based on the number of instrument stations used in the work.

d. Calculate the adjustments required if the misclose is acceptable.

e. Apply the adjustments and prepare a list of reduced levels for the Pegs/Marks A to K.

Question 2

Aq

D

Cq

The figure above shows three stations, A. B and C. The horizontal distances between the stations have been surveyed and the following results obtained.

AB = 91.437m

BC = 72.697m

CA = 128.443m

The position of Station B in relation to A and B needs to be checked. To do this, Station D is located 62.429m from A so that the distance DB can be used to check the position of the peg B.

a. Calculate the horizontal distance DB.

b. Calculate slope distance that should be obtained when DB is measured if D is known to be 3.348m below B.

c. Comment on the maximum accuracy of measurement you would expect in measuring BD, if a steel tape is used, care is taken and adjustments are made for slope, tension and temperature.

Question 3

A closed survey traverse was made of four stations A, B, C and D The survey data and requirements for the survey are shown below.

a. Adjust the observed angles and partial coordinates of the traverse and determine the coordinates of the four stations and present the computations in the format shown in Table 6.1 of the text book

b. Show any additional calculations made on calculation sheets.

c. Comment on the quality of the traverse on both angle measurements and distance measurements.

d. Sketch the traverse showing the north point coordinates for each station and adjusted bearings and distances for each line.

The bearing of Line AB is 283°05'52"

The Coordinates of Station A are 232.570E 516.255N

The maximum allowable error for the angle misclose is allow ±20 (n)°3 seconds, using a 1" theodolite. The accuracy of the survey coordinates close must be better than 1 in 2500.

All calculations should be to 4 decimal places in metres for distances, and angles and bearings should be calculated to the nearest second. Results should be reported to three decimal places and to the nearest second.

The following information was obtained from Field Books:

Line	Horizontal length (m)
AB	64.885
BC	22.321
CD	42.316
DA	42.254
Means of FL and FR observed horizontal angles		Angle (DMS)
ABC		80°19'04"
BCD		119°42'59"
CDA		100°17'05"
DAB		59°41'08"

Question 4

A project modification requires establishment of a new survey control point because lines of sight to existing survey marks are obscured. It is proposed to set up the new control point (Station F) by intersection, setting up a theodolite at existing survey control points (Station C and Station D) whose coordinates are known.

Coordinates for the known control points are

Station C: 271.74E     72.81N

Station D: 431.23E     154.97N

The peg for the new control point was placed at F after checking that there were clear lines of sight to station C and station D, and checking that the location of F allowed the obscured project area to be observed. When the peg at F was securely placed, the observations were made from station C and station D to obtain the angles FCD and FDC. Observations were taken FL and FR, and each angle was measured three times. The results of these observations of the internal angles of Triangle FCD obtained from the Field Book were:

Angle FCD 48°01 '14" and Angle FDC 72°58'46" Compute the following:

a. Bearing and distance of CD

b. Coordinates of the new Station F

c. Bearing and distance CF

d. Bearing and distance DF

Question 5

The following list shows obsen-ations of an angle that was repeated six times to increase the precision of the mean.

a. Determine the mean of this set of 6 observations.

b. Determine the standard deviation of this set of 6 observations

c. Use the t-distribution table to determine whether any of the observations in this set of six should be considered outliers, that should be disregarded in calculating the mean and standard deviation of the set of observations. Use the 95% acceptance criterion to accept that errors in observations are due to random variations only.

d. If outliers are found, recalculate the mean and standard deviation of the reduced set of acceptable observations and calculate the standard error of the mean.

e. Explain what the value of the standard error of the mean indicates about the true value of the measurement if it is assumed that the variation is due only to random variation

Observation	Observed value (DMS)
1	233°18'01"
2	233°18'43"
3	233°18'43"
4	233°18'44"
5	233°18'45"
6	233°18'41"

Question 6

The height difference between two points A and B is measured with a total station and following results are obtained.

With the total station at A

Slope distance = 256.347 m

Zenith angle = 92°25'51"

Height of the instrument at A = 1.550 m Height of the reflector at B = 1.405 m

With the total station at BI Slope distance = 256.352 m Zenith angle = 87°37'42"

Height of the instrument at B = 1.625 m Height of the reflector at A = 1.530 m

If the height of point A is 19.072 in, calculate the height of point B.