# survey camp viva tips

before going to viva you should know these points:**General principles of surveying are**

Working from whole to part: In this principle the whole area is first framed out

by main stations and survey lines. Then the area is divided into no. of wellconditioned

triangles and linear measurements are done which prevents in error

accumulation.

Location of new control point by measurements from two control points: From

fixed reference points new stations are fixed from at least two measurements.

Measurements may be linear or angular (by chain, tape, theodolite, compass).

**In a survey camp a single group has to conduct a detailed survey for**

Preparation of a topographic map of the given area

Selection of a suitable Road alignment

Selection of a suitable Bridge site**The general objectives of the survey camp are listed below-**

To become familiar with the surveying problems those are likely to arise during

the field works.

To develop confidence in actual field surveying.

To become familiar with different instruments, their functions and handling for

their use in surveying.

To become familiar with the spirit and importance of teamwork, as surveying

cannot be carried out by a single person.

To complete the task or the project within the given time limit.

To collect the required field data in a systematic way.

To compute and manipulate the observed data in the required accuracy and

present it in theoretical, tabular and diagrammatical forms that it is easily

understood by other engineering professionals.

### SCOPE OF WORK FOR SURVEY CAMP

**Topographic Map Presentation**

**Details**

Area Coverage:1.5 to 2.0 hectares

Scale for the Plot of Major Traverse: 1:1000

Scale for the Plot of Minor Traverse: 1:500

Scale for Plot of Topographic Map: 1:500

Contour Interval:1 m (depending upon the site relief)**Control Points Establishment**

• At least 25-35 stations (Main control stations)

• Two sets of Horizontal Angle, One set of Vertical Angle

• Distance measurement by three-way taping and by EDM (1:2000 accuracy)

• Vertical control by Leveling, check by trigonometric leveling

• Fly Leveling, at least 0.5 – 1.0 km (± 25√K mm accuracy)

• Leg ratio: Major Traverse 1:2, Minor Traverse 1:3

#### Road Alignment Survey

•At least 500 m to 700m or more stretch

•Scale for Plan: 1:1000

•Scale for Longitudinal section: V – 1:100 & H – 1:1000

• Cross section: 20 m interval, scale same for V & H – 1: 100

•Left right observation: 10 m minimum on either side of proposed center line

Curve Setting

• Horizontal curve by both linear and angular method

• Vertical curve setting with gradient (7 to 12) %

#### Bridge Site Survey

• up-stream details at least 120 m, Downstream details at least 40 m

• Scale for plotting minimum area of observation of coverage plan 1:500

• Contour interval: 2.0 m or depending upon the site relief

• Longitudinal section: H=1:200,V=1:100

• Cross section: (10 to 20) m interval (depending upon the site relief), scale

H=V=1:100

**TOPOGRAPHICAL SURVEY**

**OBJECTIVES**

### NORMS (TECHNICAL SPECIFICATIONS)

## METHODOLOGY

#### points which should be kept in mind for appropriate selection of major

traverse control points forming the closed traverse around the premises of the area to

be surveyed are summed up as follows:

#### points needed to be

kept in the mind while fixing major traverse stations are as follows:

### Measurement of traverse angles

**Sum of interior angles = (2n – 4) *90°**

**Closing error = (2n – 4) *90° – Σ Observed sum of internal angles**

#### Bearing computation of the traverse legs

**Bearing of successive line = Fore bearing of the previous line + clockwise traverse**

**angle ± 180° or 540°**

**Note:**

### Consecutive co-ordinates

#### In a closed traverse, the algebraic sum of the latitudes and departures must be zero if

linear as well as angular measurements of the traverse along with their computations

are correct. If not, the distance between the starting station & point or position of the

same station obtained by the calculation is known as closing error.

**Bowditch’s method**

**Bowditch’s method**

**proportional to √L**and

**inversely proportional to √L**where ‘L’ is the length of a line. The method is applicable when both

**Total error in latitude (or departure) ***

__Length of that side__**Perimeter of traverse**

**Transit Method**

**angular measurements are of more precision than linear**

**measurement.**According to this rule, the total error in latitude and in departure is

**Total error in Latitude (or Departure) ***

__Latitude (or Departure) of that line__**Arithmetic sum of Latitudes (Departures)**

**Plotting of major traverse stations**

## Leveling

## Adjustment of level

#### i. Temporary adjustment of level

**1. Setting up the level**

**2. Leveling up**

**3. Removal of parallax**

#### ii. Permanent adjustment of level

## a. HI Method

## b. Rise and Fall Method

## Arithmetic check

**ΣB.S. – ΣF.S. = ΣRise – ΣFall = Last R.L. – First R.L.**

#### steps followed while

carrying out the detail survey are summed up as follows:

## Contouring

#### Characteristics of Contours

**1. Two contour lines of different elevations cannot cross each other. They can cross**

**each other only in the case of overhanging cliff.**

**2. Two contour lines of different elevations cannot unite to form a single. If they do,**

**it is only in the case of vertical cliff.**

**3. Closely spaced contour lines represent a steep slope. Broadly spaced contour lines**

**represent a gentle slope. Equally spaced contour lines represent a uniform slope.**

**A series of straight, parallel and equally space contours represent a plane surface.**

**4. A contour line cannot split into two or more contour lines.**

**5. A series of closed contour lines with higher value of contour i.e. with contour**

**having higher value of elevation inside represent a hill where as a series of closed**

**contour lines with lower value of contour inside represent a pond or the depressed**

**land.**

**6. A contour line must close upon itself, though not necessary within the limits of the**

**map.**

**7. Contour lines cross a watershed or the ridge line at right angles. They form curves**

**of U-shaped round it with the concave side of the curve towards the higher ground.**

**8. Contour lines cross a valley line at right angles. They form sharp curves of Vshaped**

**across it with the convex side of the curve towards the higher ground.**

**9. The same contour appears on the either side of a ridge or valley, for the highest**

**horizontal plane that intersects the ridge line must cut it on the both the sides. The**

**same is true of the lower horizontal plane that cuts a valley.**

### Interpolation of the Contour lines

**By estimation**

### By Estimation

### By Arithmetic Calculations

### By Graphical Method

## BRIDGE SITE SURVEY

#### NORMS (TECHNICAL SPECIFICATIONS)

#### The following things were considered while selecting a bridge site:

### Triangulation

### Reciprocal Leveling

## ROAD ALIGNMENT

**OBJECTIVES**

**METHODOLOGY**

## Deflection angle (Δ) = (360° or 180°) – Observed angle.

## Simple Circular Curve

**Length of tangent: R tan (Δ/2)****Where, R = radius of simple circular curve Δ = deflection angle****Length of long chord: 2R sin(Δ/2)****Apex distance: R (sec(Δ/2) – 1)****Mid ordinate: R (1 – cos(Δ/2))****Length of curve: **__πRΔ__** 180°****Chainage of T1: Chainage of IP – R tan (Δ/2)****Chainage of T2: Chainage of T1 + **__πRΔ__** 180°**

__πRΔ__

__πRΔ__

## Super-elevation

https://freeengineeringnote.com/civil/2018/02/28/survey-viva-question-collection/