Sign Up

Sign Up to The Constructor to ask questions, answer questions, write articles, and connect with other people. VIP members get additional benefits.

Have an account? Sign In
Continue with Facebook
Continue with Google
Continue with LinkedIn
Continue with Amazon
or use


Have an account? Sign In Now

Sign In

Login to The Constructor to ask questions, answer people’s questions, write articles & connect with other people. VIP members get additional benefits.

Sign Up Here

Free Signup or Login to continue Reading...

Continue with Facebook
Continue with Google
Continue with LinkedIn
Continue with Amazon
or use


Forgot Password?

Don't have account, Sign Up Here

Forgot Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

Have an account? Sign In Now

Sorry, you do not have permission to ask a question, You must login to ask question. Become VIP Member

Free Signup or Login to continue Reading...

Continue with Facebook
Continue with Google
Continue with LinkedIn
Continue with Amazon
or use


Forgot Password?

Don't have account, Sign Up Here
Become VIP Member
The Constructor Logo The Constructor Logo
Sign InSign Up

The Constructor

The Constructor Navigation

  • VIP
  • Articles
    • VIP Exclusive
    • Recent Articles
    • Popular Articles
    • Write Article
  • Questions
    • Recent Questions
    • Popular Questions
    • Polls
    • Ask a Question
  • Categories
    • How To Guide
      • Material Testing Guide
    • Concrete
    • Building
      • Brick Masonry
      • Building Materials
      • Building Tips
    • Construction
      • Equipments
      • Management
    • Digital tools
    • Geotechnical
      • Foundation
Search
VIP Dashboard

Mobile menu

Close
Ask a Question
  • VIP
  • $ Earn Money
  • Shop Merchandise
  • Questions
    • Popular Questions
    • Trending Questions
    • New Questions
    • No Answer Questions
  • Ask Question
  • Write Article
  • Building
    • Brick Masonry
    • Building Materials
    • Building Tips
    • Formwork/Shuttering
  • Concrete
    • Concrete Admixtures
    • Cement
    • Concrete Cracks
    • Concrete Properties
  • Construction
    • Construction Equipments
    • Construction Management
    • Construction Project
    • Estimating & Costing
  • How To Guide
    • Material Estimation
    • Repair/Protection Guide
    • Material Testing Guide
    • Mix Design Guide
    • Rate Analysis
  • Geotechnical
    • Foundation Engineering
    • Ground Improvement
  • Structural Engineering
    • Strengthening of Structure
    • Structual Inspection
    • Structural Detailing
  • Surveying
  • Tips

What is height of instrument and Rise & fall method of levelling?

Home/ Questions/Q 28867
Next
In Process

Do you need to remove the ads? Become VIP Member

Asked: January 11, 20192019-01-11T18:06:17+05:30 2019-01-11T18:06:17+05:30In: Construction Site Related
Muksit Pathan
Muksit Pathan

Muksit Pathan

  • 2 Questions
  • 0 Answers
  • 0 Best Answers
  • 28 Points
View Profile
Muksit Pathan User

I want to what is height of instrument and Rise & fall method of levelling? What is the method to calculate reduced level.

  • 5
  • 4 4 Answers
  • 10,701 Views
  • 0 Followers
  • 1
  • Share
    Share
    • Share on Facebook
    • Share on Twitter
    • Share on LinkedIn
    • Share on WhatsApp

4 Answers

  • Voted
  • Oldest
  • Recent
  1. AdityaBhandakkar

    AdityaBhandakkar

    • 11 Questions
    • 250 Answers
    • 2 Best Answers
    • 0 Points
    View Profile
    AdityaBhandakkar User
    2020-08-02T09:27:17+05:30Added an answer on August 2, 2020 at 9:27 am

    In simple English,

    The height of instrument always measures form benchmark.

    The benchmark is a Point on the sea derived from mean sea level.

    Rise and Fall method:

    The rise and fall of ground between two adjacent ranging rod are measures with levelling staff.

    • High reading= fall of ground level.
    • Low reading= rise of ground level.

    RL = HI – FS

    RL= Reduced level

    HI = Height of instrument

    FS= Foresight distance.

    • 40
    • Share
      Share
      • Share on Facebook
      • Share on Twitter
      • Share on LinkedIn
      • Share on WhatsApp
  2. nikeetasharma

    nikeetasharma

    • 21 Questions
    • 303 Answers
    • 0 Best Answers
    • 2,940 Points
    View Profile
    nikeetasharma Guru
    2020-09-07T17:39:11+05:30Added an answer on September 7, 2020 at 5:39 pm
    • Height of Instrument :

    It is the method which deals with the obtaining of RL of the line of collimation by adding BS reading of a known RL point. Thus, RL of the line of collimation is called the Height of Instrument. It is always measured from the benchmark. Hence the benchmark is the point on the sea derived from mean sea level.

    – method to calculate RL;

    height of collimation (H of C) = reduced level(R.L.) + backsight (B.S.)

    reduced level (R.L.) = height of collimation (H of C) – foresight (F.S.)

    reduced level (R.L.) = height of collimation (H of C) – intermediate sight (I.S.)

     

    • Rise & fall method :

    It is the method which gives the difference of elevation between consecutive points by comparing each point after the first that immediately preceding it. Rise and fall are indicated by the difference in staff reading. After that RL is found by adding the rise to or subtracting the fall from the reduced level of the preceding point.

    – method to calculate RL;

    fall (F) = foresight (F.S.) – backsight (B.S.)

    fall (F) = intermediate sight (I.S.) – backsight (B.S.)

    rise (R) = backsight (B.S.) – foresight (F.S.)

    reduced level (R.L.) = precede reduced level  + rise (R)

    reduced level (R.L.) = precede reduce level – fall (F)

    • 33
    • Share
      Share
      • Share on Facebook
      • Share on Twitter
      • Share on LinkedIn
      • Share on WhatsApp
  3. aviratdhodare

    aviratdhodare

    • 36 Questions
    • 252 Answers
    • 0 Best Answers
    • 835 Points
    View Profile
    aviratdhodare
    2020-08-21T13:31:00+05:30Added an answer on August 21, 2020 at 1:31 pm

    To obtain the reduced level of a point in the field from staff readings, we have 2 methods:

    1. Height of Instrument or Collimation method
    2. Rise and fall method.

    Height of instrument method deals with obtaining the RL of the line of collimation by adding BS reading of a point whose RL is known. The RL of line of collimation is called Height of Instrument. From this, the staff readings of all intermediate stations is subtracted to get the RL at those points.

    Now, what is the rise and fall method?

    Here, instead of calculating the height of instrument, we calculate the difference of staff readings at the two stations. The two stations where staff readings are taken are such that we know the RL of ground of one station and we want to find the RL of other.

    A level is set at such a position from where max. no of stations can be visible. Now, the staff is placed at the station whose RL is known and the reading is observed say R1. The staff is then transferred to a station whose RL is to be determined and the reading is observed say R2.

    Now, if R1 > R2, it means ground at former station is lower than ground at latter station. So, there is rise in ground surface

    Similarly, if R2 > R1, the ground at latter station is deeper / lower than ground at former station. So there is a fall in ground surface

    Now that you know what rise and fall is, the question arises how to use this concept to obtain RL of various successive stations?

    After taking readings at two stations, the difference of readings i.e. (R1 – R2) is added to the RL of first station to get the RL of second station

    => RL of Station 1 +(R1-R2) = RL of Station 2

    Now to find the RL of third station, the staff reading is observed say R3 and (R2-R3) is obtained.

    Then,

    RL of station 2 + (R2-R3) = RL of station 3

    This can be used indefinitely till the last point whose RL is required is reached.

    The difference of staff readings is nothing but the rise or fall of ground.

    if fore sight reading is greater than back sight reading, there is fall in ground surface. This fall is then subtracted from RL of previous station to obtain RL of next station

    This method is a bit laborious as staff reading at each station after the first, is compared with that of the preceding station

    There are 3 checks for arithmetical accuracy. These are the “sum of back sight readings minus sum of fore sight readings should be equal to the difference between the sum of rises and sum of falls which in turn should be equal to the difference between first RL and last RL”

    • 33
    • Share
      Share
      • Share on Facebook
      • Share on Twitter
      • Share on LinkedIn
      • Share on WhatsApp
  4. Madeh Izat Hamakareem

    Madeh Izat Hamakareem

    • 0 Questions
    • 40 Answers
    • 3 Best Answers
    • 1,229 Points
    View Profile
    Madeh Izat Hamakareem EDITOR
    2019-08-01T01:36:39+05:30Added an answer on August 1, 2019 at 1:36 am

    Height of Instrument (HI) method: consider the readings taken in the operation shown below:

    Reduce level can be computed using the following expression:

    RL of a point = HI – FS = ( RLBM +BS) – FS

    Arithmetic check: ΣBS – ΣFS= Last RL – first R

    Where:

    RL: Reduce Level

    HI: height of instrument

    FS: foresight

    BS: Back sight

    BM: Bench Marks

     

    Rise and fall (RF) method: the rise or fall of the ground between successive rod stations is considered. For the same instrument set up,

    If 2nd rod reading > first rod reading ⇒ fall

    If 2nd rod reading < first rod reading ⇒ rise

    Then RL of 2nd station = RL of first station – fall       or

    RL of first station + rise

    • 5
    • Share
      Share
      • Share on Facebook
      • Share on Twitter
      • Share on LinkedIn
      • Share on WhatsApp

You must login to add an answer.

Free Signup or Login to continue Reading...

Continue with Facebook
Continue with Google
Continue with LinkedIn
Continue with Amazon
or use


Forgot Password?

Need An Account, Sign Up Here

Sidebar

Popular Articles

  • Gopal Mishra

    Types of Foundation for Buildings and their Uses [PDF]

  • Padmanabhan G

    Methods of Rainwater Harvesting [PDF]: Components, Transport, and Storage

  • Gopal Mishra

    Compressive Strength of Concrete -Cube Test [PDF], Procedure, Results

  • Gopal Mishra

    Calculate Quantities of Materials for Concrete -Cement, Sand, Aggregates

  • Fasi Ur Rahman

    Standard Size of Rooms in Residential Building and their Locations

Recent Articles

  • Madeh Izat Hamakareem

    Tips and Rules for Design of Reinforced Concrete Columns

  • Santoshi M

    Polyrok: A Sustainable Recycled Plastic Aggregate Alternative for Mineral Aggregate

  • Santoshi M

    ByBlock: An Advanced Construction Material for a Better Future

  • Ravi Panwar

    Collapse of the Tacoma Narrows Bridge: A Case Study

  • Ravi Panwar

    Petra Jordan: A World Heritage Site Under Risk

Recent Questions

  • Dilan Kasun

    why risk of efflorescence formation in cement based materials is high in coastal areas?

    • 1 Answer
  • KomalBhandakkar

    What is the percentage of carbon in wrought Iron?

    • 2 Answers
  • Preet Chovatiya

    Which country provides highest salary to the civil engineer?

    • 1 Answer
  • RiyaJames

    What are the important points of FIDIC Contract we should keep in mind during tendering?

    • 0 Answers
  • Naif Alwadai

    What is the difference between Airport, Aerodrome and Airfield?

    • 0 Answers

Footer

Know More

  • Home
  • About Us
  • Contact Us
  • Privacy Policy
  • Terms & Conditions

Connect With Us

  • Ask Question
  • Write Article
  • VIP Membership
  • Popular Questions

© 2009-2020 The Constructor. All Rights Reserved.