Top 8 Most Asked Surveying Questions

1: When the contours intermix i.e. unite at a place that place is known as:

A: Cliff ,    B: Over hanging cliff        C: Ridge              D: Valley

2: Two contours of different elevations do not cross each other except in case of a :

A: Cliff      B: Ridge         C: Overhanging Cliff         D: Valley 

3:The Limiting length of an Offset should be:

A: 5 m       B: 15m        C:30m     D: 50 m

4:In levelling the correction for curvature  ( in meters ) is equal to:

A: 0.00785 Square of D  ,    B: 0.0785 Square of D  , C: 0.0112 Square of D ,   D:0.0673 Square of D

Where D is distance from the level to the staff reading in meters

5: The vertical distance between two consecutive contours is called: Contour Interval 

6: Reduced level of apoint is its elevatiob with refernce to :Datum Level

7:The error which is not completely eliminated in reciprocal levelling : Error Due to Refractionn 

8: THE first reading from a level station is: Back Sight

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Solved Objective questions on surveying

1: The object of surveying is to prepare a:
(a) Map
(b) Cross-section
(c) Drawing
(d) Model.
Answer. (a)


2: The main principle of surveying is to work from:
(a) The part to the whole.
(b) The whole to the part.
(c) The centre to the boundary
(d) The boundary to the centre.
Answer. (b)


3: A 20 m chain is divided into:
(a) 50 links
(b) 100 links
(c) 150 links
(d) 175 links
Answer. (b)


4: The length of a link in a chain is:
(a) 20 cm
(b) 30 cm
(0) 35 cm
(d) 40 cm 
 Answer. (a)


5: For ranging a line, the number of ranging rods required is:
(a) At least two
(b) At least three
(c) At least four
(d) At least five.
Answer. (b)


6: The walk step of a man is considered equal to:
(a) 80cm
(b) 90 cm
(c) 100 cm
(d) 110 cm
Answer. (a)


7 : ln chain survey the area is divided into :
(a) Circle
(b) Square
(c) Triangles
(d) Rectangulars.
Answer. (c)


8: The preliminary Inspection of the area to be surveyed is known as:
(a) Rough survey.
(b) Primary survey
(c) Route survey
(d) Reconnaissance survey.
Answer. (d)


9: ln a prismatic compass zero is marked on the:
(a) East end.
(b) West end.
(c) North end.
(d) South end.
Answer. (d)


10: The closing error in a closed travers is adjusted by:
(a) Lenmanns rule
(b) Slide rule.
(c) Bowditch’s rule.
(d) Simpson’s rule.
Answer. (c)


11: The principle of plane table is:
(a) Traversing.
(b) Parallelism.
(c) Triangulation.
(d) All the above.
Answer. (b)


12: The working edge of the alidade is known as the:
(a) Parallel edge.
(b) Bevelled edge.
(c) Parallax edge.
(d) Fiducial edge.
Answer. (d)


13: Inaccessible point may be located by the:
(a) Radiation method.
(b) Resection method.
(c) Intersection method.
(d) Travering method.
Answer. (c)


14: Spirit level in plane table is used for:
(a) Centring
(b) Sighting
(c) Marking north
(d) Leveliing
Answer. (d)


15: Closed travers is suitable in the survey of:
(a) River.
(b) Road.
(c) Coast lines.
(d) Ponds.
Answer. (d)


16: Prismatic compass gives the:
(a) Quadrantal Bearing.
(b) Reduced Bearing.
(c) Whole circle Bearing.
(d) None of these.
Answer. (c)


17: The line passes through zero declination is known as the:
(a) lsogonic line.
(b) Agonic line.
(c) Dip line.
(d) Contour line.
Answer. (b)


18: At the equator the dip of the needle is:
(a) 0°.
(b) 90°.
(c) 180°.
(d) 45°.
Answer. (a)


19: In the whole circle Bearing (WCB), a line is said to be free from local attraction if the
difference between the FB and BB is:
(a) 0°
(b) 90°
(c) 120°
(d) 180°
Answer. (d)


20: The surface of still water is considered:
(a) Even
(b) Smooth.
(c) Horizontal.
(d) Level.
Answer. (d)


 21: The surface tangential to a level surface is said to be a:
(a) Horizontal surface.
(b) Vertical surface.
(c) Ground surface.
(d) Levelled surface.
Answer. (a)

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TOTAL STATION

 

A total station is an electronic/optical instrument used in modern surveying and building construction. The total station is an electronic theodolite (transit) integrated with an electronic distance meter (EDM) to read slope distances from the instrument to a particular point

There are four basic types of total stations and they include the following:

1.Robotic total stations – 

One of the smoothest ways to survey an area is with the use of this device. It permits the user to control the device remotely, meaning you do not have to have an instrument operator standing by the total station. This is greatly beneficial in that you need not hire an assistant to hold the rod for you. You can be “out front” where the work is happening to make the correct decisions. There are many essential features on a robotic total station so make sure you ask about the latest technological advances that will suit your needs.

2.Imaging total stations – 

This kind of total station adds either a photographic or laser scanning element or both. With this new tool in the market, the surveyors could offer many more services that greatly benefit from these high resolution images. Moreover, the laser scanner component can capture topographic data automatically. The imaging capability provides an accurate photo documentation of the site’s existing condition, which in effect, is beneficial in generating productivity and minimizing expenses caused by re-visits to the site.

 

3.Construction Total Stations – 

These type total stations are specifically designed to aid construction efforts. These total stations are typically more rugged for the environment they will be used in and they may not have the same high precision that other total stations have. Some construction applications don’t require this high level of accuracy. Therefore, these total stations will be more economical for the particular purpose. Discuss your accuracy requirements with the manufacturer or fellow contractors before selecting the type of construction total station you will purchase. Another good source of information might be your local surveyor.

4.Optical Total Stations – 

This type total station is the basis for both the robotic and imaging total stations. While an optical total station can have many features, this type total station will require an instrument operator at the device. It will also not have the imagining capabilities mentioned above. This device is essentially designed for your everyday surveying applications. These instruments will typically be lower priced than the more specialized total stations above. But, with the addition of another crew person, they may not be more economical. You should again discuss these economic benefits with your equipment representative and/or other surveyors.

In sum, total stations are a must in about every surveying application. Keep in mind that there are many competing offers in the market today. Be sure that you thoroughly understand the specific purpose for each device and your application. Choosing the right “tool” to use is ninety percent of getting the job done.

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Application Of GPS In Civil Engineering

Application Of GPS In Civil Engineering

 

 

What is GPS?

The Term GPS stands for Global Positioning System. The GPS is used to locate a location
with the help of Latitude and Departure. with the help of GPS it's possible to locate a point
very precisely. GPS consist Of two main ends, the one is the Locating Sattelites and the other
 is the Receiver. Most of the people now a days are familier with GPS due to the huge use of
Smart Phones.
The Global Positioning System was first evoled for the Defence of Countries, and it's controlled
from the California. It was used for locating various places which are important from the
Defence point of view. Later on it was opened for public use. But the Same GPS System with
more Powerful receivers it can be used in the Civil Engineering Field.

How GPS Works ?

A point is located with the 18 sattelites which are orbiting around the Earth, 22,000 km above
the suface of the Earth, these sattelites are orbiting in 6 orbits, that means having 3 sattelites in
each orbit. And has a the capability to rotate a single time around Earth in 11 hours and 58
minutes. To locate a point two sattelite is requred, the more number of sattelites are in use the
more precision can be obtained.

Application In Civil Engineering

Most of the Companies uses manual procedure of Surveying (i.e. Levelling, Countouring,
Compass Surveying) to Prepare Countour Maps, Longitudinal Section Of Roads, Allignment
of Roads, Bridges etc. But many Broad Companies in India and abroad uses GPS to locate
different points, preparing Contour maps, giving Allignments of Roads, Bridges where the
 precision is very essential or it may ruine the whole project for a simple error in surveying,
on those places the survey work can be done with the help of Global Positioning System.

Advantages

1. It helps to survey with many times greater Precision.
2. It helps to complete a Survey with lesser time and thus helps to cut down the 
3. Completion Period.
4. It Reduces the Difficulty of taking manual measurements to great extent.
5. With GPS there is a very less chances of error.error only come due to the Instrument malfunction.

 

Disadvantages

1. The main Disadvantage is that, it requires high initial investments.
2. To conduct such High End Survey works and to operate such Electronic Equipments much skilled persons are required.

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-==>>LEVLLING==>>

-==>>LEVLLING

The primary reference at water-level recording stations is a set of stable bench-marks, installed in locations where their level should not change. Upon initial set-up of a station, the levels of the  relevant parts of the installation are established and recorded by means of accurate levelling. At least every two years, the levels of the staff gauges, sensor level, internal gauge, tower structure and benchmarks should be measured relative to each other as a check that records are not in error
due to bank subsidence or other movement. Accurate levelling is thus a particularly important part of site establishment, installation and quality assurance. All staff shall be thoroughly familiar with its theory and practice. Levelling and surveying methods are also used for measurements of river channel and lake
configurations. Often, less accurate methods can be used for this work than for water-level recording stations, although the techniques are common.

==>>TERMS USE IN LEVLLING


Differential levelling => is the term applied to any method of measuring directly with a graduated staff the difference in elevation between two or more points.

Precise levelling=>  is a particularly accurate method of differential levelling which uses highly accurate levels and with a more rigorous observing procedure than general engineering levelling. It aims to achieve high orders of accuracy such as 1 mm per 1 km traverse.

 level surface=>A level surface is a surface which is everywhere perpendicular to the direction of the force of
gravity. An example is the surface of a completely still lake. For ordinary levelling, level surfaces at different elevations can be considered to be parallel.

=>
A level datum is an arbitrary level surface to which elevations are referred. The most common surveying datum is mean sea-level (MSL), but as hydrological work is usually just concerned with levels in a local area, we often use:
An assumed datum, which is established by giving a benchmark an assumed value (e.g. 100.000
m) to which all levels in the local area will be reduced. It is not good practice to assume a level which is close to the actual MSL value, as it creates potential for confusion.

=>
A reduced level is the vertical distance between a survey point and the adopted level datum. A bench mark (BM) is the term given to a definite, permanent accessible point of known height above a datum to which the height of other points can be referred.

=>

Height of Collimation is the elevation of the optical axis of the telescope at the time of the setup. The line of collimation is the imaginary line at the elevation

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==>>BASIC INSTRUMENTS USED IN SURVEYING==>>

=> Chain or tape
=> Arrows
=> Ranging rods
=> Cross staff
=> Offset rods
=> Pegs
=> Plumb bob

 Chain:==>>

The chain is composed of 100 or 150 pieces of galvanized mild steel wire, 4mm in diameter called links .The ends of each link are bent into a loop and connected together by means of three oval rings. The ends of the chain are provided with handles for dragging the chain on the ground, each wire with a swivel joint so that the chain can be turned without twisting. The length of the chain is measured from the outside of one handle to the outside of another handle.

Following are the various types of chain in common use:
1) Metric chains
2) Gunter` s chain or surveyors chain
3) Engineers chain
4) Revenue chain
5) Steel band or Band chain


 Tapes==>>
The following are the various types of tapes
=> Cloth tape
=> Metallic tape
=> Steel tape
=> Invar tape
Among the above, metallic tapes are widely used in surveying. A metallic tape is made of varnished strip of waterproof line interwoven with small brass, copper or bronze wires. These are light in weight and flexible and are made 2m, 5m 10m, 20m, 30m, and 50m.


Arrows=>
Arrows are made of good quality hardened steel wire of 4 mm diameter. The arrows are made 400 mm in length, are pointed at one and the other end is bent into a loop or circle

Ranging rods==>>
Ranging rods are used to range some intermediate points in the survey line The length of the ranging rod is either 2m or 3m. They are shod at bottom with a heavy iron point. Ranging rods are divided into equal parts 0.2m long and they are painted alternately black and white or red and white or red, white and black. When they are at considerable distance, red and white or white and yellow flags about 25 cm square should be fastened at the top.


Cross staff==>>
The simplest instrument used for setting out a right angle. The common forms of cross staff are: Open cross staff, French cross staff,Adjustable cross staff

OFFSET ROD==>>
The offset rod is used for measuring the off set of short lengths. It is similar to a ranging rod and is usually of 3m lengths.

PEGS==>>
These are rods made from hard timber and tapered at one end, generally 25mm or 30mm square and 150mm long wooden pegs are used to mark the position of the station on.

PLUMB BOB==>>
While chaining along sloping ground, a plumb bob is required to transfer the points to the ground.

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==>>QUESTION BASED ON SURVEYING<<==

1. Define Tacheometer.
It is an ordinary transit theodolite fitted with an extra lens called analytic
lens. The purpose of fitting the analytic lens is to reduce the additive constant to zero.


2. Define Substance bar:
A Substance bar is manufactured by Mr. Kern. The length of the substance bar is
2m (6ft) for measurement of comparatively short distance in a traverse. A Substance bar
may be used as a substance base. The length of the bar is made equal to the distance
between the two targets.


3. What do you mean by Fixed hair method:
In this method, the stadia wires are fixed (or) fitted at constant distance apart.


4. State Stadia intercept:
The difference of the distance between the top and bottom cross hairs is called as staff
intercept


5. What do you mean by tangential method:
In this method, the stadia hairs are not for taking readings. The readings being
taken against the horizontal cross hair.
.
6. The tangential method:
In this method, the stadia hairs are not for taking readings. The readings being
taken against the horizontal cross hair.


7. What is the principle of stadia method?
The method is based on the principle that the ratio of the perpendicular to the base
is constant to similar isosceles triangle.


8. What are the systems of tacheometry measurements?
The stadia system
The tangential system
Measurement by means of special instrument.


9. Define Sub tense method:
In this method stadia interval is variable. The staff intercept is kept fixed while
the stadia interval is variable lines.


10 State Staff intercept:
The difference of the reading corresponding to the top and bottom stadia wires.


11. What are the merits and demerits of movable hair method?
Merits:
Long sights can be taken with greater accuracy than stadia method
The error obtained is minimum
Demerits:
The computations are not quicker
Careful observation is essential


12. Define Analytic lens:
Analytic lens is an additional lens placed between the diaphragm and the
objective at a fixed distance from the objective. This lens will be fitted in ordinary transit
theodolite. After fitting this additional lens the telescope is called as external focusing
analytic telescope. The purpose of fitting the analytic lens is to reduce the additive
constant to zero.

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