Thumb rules for designing a Column layout | Civil Engineering





Guidelines to be followed for making a column layout

In this article, we will go through the essential thumb rules to be followed for giving a column layout. Ofcourse columns have to be designed in accordance to the total forces acting on the structure, but apart from that, it is essential for every Civil engineer and Architect to remember a few thumb rules so that they are prevented from making mistakes.

Three thumb rules to be followed are as follows:

  1. Size of the Columns
  2. Distance between Columns
  3. Alignment of columns

Minimum Size of RCC columns

The size of the columns depends on the total load on the columns. There are axial loads and lateral loads. Large beam spans induce bending moment not only in the beams, but also in columns which are pulled by the stresses in the beams. It is important to use advanced structural design software like ETabs or Staad pro. I highly recommend every structural designer learn these software. The thumb rules are for general designing in very small projects.

For this general thumb rule, we will assume a structure of G+1 floors high, using standard 6″ walls.

Minimum size of an RCC column should not be less than 9”x 9” (225mm x 225mm) with 4 bars of 12 MM Fe500 Steel.

These days the minimum I use in my projects is 9″ x 12″ (225 mm x 300mm) with 6 bars of 12 MM Fe500 steel. You can never go wrong with strong columns. I also recommend use of M20 grade concrete for the structure (ratio 1 part Cement : 1.5 parts Sand : 3 parts Aggregate with 0.5 parts water by volume). I recommend use of 8 MM stirrups at a distance of 150 MM center to center throughout the length of column.

This setup of 9″ x 12″ RCC columns is safe for G+1 Floors. There are a lot of other considerations, but this is just a thumb rule.

Span (distance) between two columns

For the above column setup, a span of up to 5 meters is quite safe. One can use beams of size 9″ X 12″ (225 MM x 300MM) with a slab thickness of 5″ (125 MM) cast in M20 concrete for spans up to 5m. There are other considerations like secondary and tertiary spans, point loads and wall loads which have to be considered. It is complicated, but thumb rules can work if the structure is simple. It is always recommended to use structural design software like ETabs or Staad pro for design.

In a beam of up to 5 meters length, secondary spans of up to 4 meters, wall loads of up to 8 kN per running meter, I can use steel as below.

  • Top Steel – 2 bars of 12 MM
  • Crank bars – 2 bars of 12 MM, cranked at an angle of 45° at a distance of L/4 at both ends of a simply supported beam
  • Bottom Steel – 3 bars of 12 MM.

This configuration can change depending on a lot of factors.

Alignment of Columns

Placing of columns depend completely on the plan. A planner has a very important job. A grid column placement is always preferred in order to reduce point loads and unnecessary complications while construction. This reduces the cost of construction as well as time required for construction. Beams which have continuity with other simply supported beams have reduced bending moments, and thus require less steel and concrete depth to be safe.

Columns have to be connected with each other for smooth transfer of loads. An experienced planner will keep such things in mind when planning the structure.

In the next article, I will explain these three thumb rules with the help of an example “Column Layout for a Residence“.

Recommended Reading:

Introduction to design of RCC Structures

Building Design Guide which includes design of:

  1. RCC columns
  2. RCC beams
  3. Foundations
  4. Staircase


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  1. #1 by Ghulam Mustafa Vira on September 9, 2011 - 10:58 am

    wow gr8 stuff thanx

    • #2 by BenzuJK on September 9, 2011 - 11:53 am

      Hello Mustafa,
      I am glad our article has been of help to you. Do keep visiting.
      Cheers 🙂

      • #3 by Ringwang on December 22, 2011 - 1:36 am

        Dear Sir/madam.
        My site plan total area is 45’X40′. I required longest distant b/w two coulmn is 20ft and 10ft. can you suggest me what size of column i have to take and also beam depth. and types.

        • #4 by Ringwang on December 22, 2011 - 3:01 am

          i need one office room for the five empolyer and one for the cheif person. also two toilet. and verandha of 7ft. please how i have to make the column layout

        • #5 by BenzuJK on July 26, 2013 - 5:33 pm

          Hello Ringwang,

          You can now approach our experts at Civil Projects Online for advise and also for getting the structural design done.

          Design Services by Civil Projects Online

      • #6 by awais on April 2, 2012 - 9:27 pm

        thanks

      • #7 by ADIL YOUSAF ADIL on August 13, 2012 - 5:05 pm

        thanks for this good welfare

      • #8 by Abdul on September 22, 2012 - 7:54 pm

        Hi Benz!!
        I really find this site educative..I am a new bee in this field..I am now planning to construct a 2-storey residential house with rooftop..is my 25cmX25cm column with 4-20mm rebars is safe? Average distance between column is 3.5m..waiting for your valuable comment..thanks a lot.
        Sincerely..
        Abdul

      • #9 by venkatesh on November 21, 2014 - 11:06 am

        Hi..

        It is really very informative.

        Thanks a lot…!

  2. #10 by Poonguzhale.V on September 27, 2011 - 2:53 am

    worth stuff. thanks a lot

    • #11 by sharif on November 13, 2012 - 3:39 am

      Hello dear
      I have some question in column and beam
      about column please tell me the minimum and maximum
      steel bars in column and beam
      numbers and dia of steels

  3. #12 by Vaibhav kashyap on December 3, 2011 - 4:42 am

    Igts really worth article…..
    Thnx…..

  4. #13 by sunita on January 31, 2012 - 3:02 am

    Really helpful article
    Thanks for sharing

  5. #14 by rhon ammang on February 15, 2012 - 11:14 pm

    A BIG HELP 4 ME,,THANKS

  6. #15 by YTSRAO on March 11, 2012 - 11:50 pm

    I am new to RCC & Structural design. Can i know suitable books for Slab, beam, Staircase designs etc.

    • #16 by BenzuJK on December 7, 2013 - 5:15 am

      There are a lot of books, most of them have the same technical information. My personal favourite was a book by Shah-Kale. Very easy to understand and learn structural design.

  7. #17 by Raju on March 20, 2012 - 6:46 pm

    I’m building a 2 storied residential building (800) sq.ft. There are 12 columns. height of each column from base to floor level is 9 ft. I want to make singletie beam of 10×12 at pl level. My engineer suggests me for 2 tie bems, one at 5′ & another at 9′ height. Is it required? pl. mail me

  8. #18 by khan on April 14, 2012 - 2:51 am

    how i calculate steel of roof if we have 20 meter short bore and 40 meter is long bore steel type is 6# and how we will convert in weight, thanks

  9. #19 by loi on April 20, 2012 - 12:08 am

    it helps me a lot…thanks for sharing.

  10. #20 by KANNAN on May 1, 2012 - 2:35 am

    Thanks

  11. #21 by Gerard on May 2, 2012 - 4:51 pm

    Sorry, if I may sound dumb as I am a new bee.
    What does ‘1 and half storey structure’ mean? A house will be either 1 or 2 storey.

    Also, would it be ok if the column size is 12″x12″ using M15 grade concrete?

    Thanks in advance.

    • #22 by BenzuJK on May 15, 2012 - 10:17 am

      Hello Gerard,
      1 and half storey is calculated by adding the length of the plinth beam and the parapet wall. When their lengths are added, they sum up to 5′ which is equivalent to half storey. This is assumed so since they have to be considered in the structural design calculations.
      As far as column size is concerned, the column size for any building is derived from its structural calculations.

      Go through the following article. It will be of help to you.
      Building design Guide | Structural Design

  12. #23 by mahantesh on July 13, 2012 - 4:56 am

    hi..its very nice article if possible mail me thumbrules for brick masonry.

  13. #24 by Gourav tiwari on July 30, 2012 - 4:49 am

    Very nice articles. Thanks for such a wonderful job.
    GhPlease mention some more thumb rule practised in civil eng.

  14. #25 by Nishi on August 22, 2012 - 9:18 am

    hey.. that was really helpful but can u tell me what should be the size of the columns and c-c distance if we are working on a large area and have to give a barrier free movement like in a hospital?
    also if we plan to give some parts double height.. will that change the dimensions of the column?

  15. #26 by Dongapar Nyikango on October 8, 2012 - 12:28 am

    Could you kindly provide with an article on how to design flat slabs. You are articles are helpful to civil engineers.
    with best wishes,
    Donga.

  16. #27 by Shweta on November 5, 2012 - 8:32 pm

    Really its very easy to understand.

  17. #28 by Rollson Lasrado on December 2, 2012 - 7:17 am

    Hey,

    tons of useful info on the site. Awesome work. Kudos! Would like to clarify a few things about though – when you say zigzag arrangment of column is wrong what exactly do you mean. i’ve come across projects where there is a basic grid but all the columns may not be alligned to form perfect rectangles. but the beams connecting four columns do form a rectangles. when you say zig zag what exactly do you mean? clarification much appreciated!

    regards,

    Rollson lasrado

    • #29 by BenzuJK on July 26, 2013 - 7:07 pm

      In this case, it means the columns should preferably in a straight line and not placed randomly.

  18. #30 by shankhpal shivdas D. on May 19, 2013 - 12:07 am

    sir,i am planned to construct g+1 storey bldg.in my village.foundation depth is 6’on hard strata i.e on hard murum strata.length of house is 50’*10.5′ .pl.advice me about r.c.c. footing, no.of columns placing of columns,reinforced bar details in column, same details about beams and slab

    • #31 by BenzuJK on July 26, 2013 - 5:11 pm

      Hello Shankpal,

      There is some good news I would like to share with you. Civil projects Online has officially launched its Architectural and Structural Design Services. You can immediately get in touch with them and get the answers to your questions. It is important for you to understand that we cannot generalize the structural design of columns and footings. It needs expertise without which it cannot be constructed safe and sound. We spend lacs of rupees on the construction of our houses because we build them once in our lifetime. Hence, it is important to go the right way and not take chances by deciding the number of columns and footings on our own.
      The entire aim of offering design services at such low costs is so that people belonging to all levels are able to afford it. We want the best for you.

      Take a look and you should definitely get in touch.


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      Look forward to hearing from you.
      Regards,
      BenzuJK

  19. #32 by Ram on July 20, 2013 - 6:13 pm

    KANNAN :
    Thanks

  20. #33 by Ram on July 20, 2013 - 6:18 pm

    hi . i need some another web sites for our civil related

  21. #34 by Ritesh kumar singh on July 20, 2013 - 10:44 pm

    nice guidance

  22. #35 by gokul on October 29, 2013 - 3:45 am

    it’s very nice

  23. #36 by victor on December 5, 2013 - 3:55 am

    Dear sir, room size 36feet /13 feet. please let me know reinforcement details of coulmns and slab. soil is gravel in loose
    condition

  24. #37 by hemanth on July 24, 2014 - 11:21 pm

    Is 12 mm iron 8 numbers enough for column size of 6″*18″ for site measuring 250 sq feet for 4 floors

  25. #38 by lakhwinder singh on September 27, 2014 - 10:34 am

    Sir.i want to construct two stories house problem is that we want to live on first floor leaving ground floor on columns for parking a car tractor area is 800sqft

    • #39 by BenzuJK on October 26, 2014 - 5:01 pm

      Dear Mr Singh,

      It would be wise to employ a Civil Engineer to guide you.

  26. #40 by ASHISH SAHU on January 10, 2015 - 11:02 am

    Hello Sir,

    Thanks for all the posts & your suggestions, it is very helpful for all peoples. Here after reading the post “thumb rules for designing column”, I have some problem. Last year I have constructed my home of G floor & made all column & beam of 9″x9″ with 4 nos. 12mm bars & used M15 concrete. Distance of all column are 12′.

    I want to construct this year one floor more (so G+1), pls suggest whether my home will be at risk or OK to survive. And another thing, Suppose in future I want to construct one more floor, How the same can be achieved???

    ….Ashish Sahu

    • #41 by BenzuJK on July 16, 2015 - 6:23 pm

      If you do that your house will collapse. Thumb rules are minimum standards and not meant to be used by layman like you. They are to be used under the supervision of a Civil engineer who is an expert in this field. If you need experts working on your project, you should be willing to pay them as well unless you want your house to collapse and your family killed under the debris.

  27. #42 by virender on January 26, 2015 - 10:47 pm

    Dear Sir\mam
    I want to know that if we are constructing a 3 storey house than what should be the distance between 2 columns. please tell the minimum distance which can be between the two coloums.

    • #43 by BenzuJK on February 18, 2015 - 12:41 pm

      There is no minimum or maximum distance. It all depends on the design. You should hire a structural designer. You are building a house for 60 years lifespan. You can get a good structural designer for Rs 7 per square feet builtup area. That is a small investment for complete peace of mind.

  28. #44 by bidul boruah on May 29, 2015 - 9:47 am

    thanks for your article

  29. #45 by nimesh on January 3, 2016 - 11:28 am

    Sir if architect plan a building with columns not in grid instead staggered.as structural engineer what are factors to be considered?

  30. #46 by aggarwal on February 16, 2016 - 7:10 pm

    I am going to develop parking flplus4 floor building. Plot size is 14m x 5m. Lift is planned. Can u advise no of columns, spacing and re in bar nose and spacing. Advise please.

  31. #47 by khawar on March 15, 2016 - 8:56 pm

    Hello, i have a question i am building a new floor on my 30 years old G+1 120 yard building. my constructor advising me to repositioning the column above floor he is using term jackling the columns like if its right to left he would reposition it to front to back on previous column.. is it safe and allowed??

  32. #48 by karthik on March 24, 2016 - 11:23 am

    centre distance between 2 Rcc
    column is 20m and other side is 25m.. may i know it is possible.. if yes please tell me what is the approximate size of the column

  33. #49 by A.Niranjan on April 18, 2016 - 11:37 am

    Dear Sir,
    we are building a rest house using eco sand bricks and our client need to construct that without concrete column.

    so i need to know if we using 3 nos steel bars which have a 32mm dia as a column in building is okey or not for the load bearing.
    our building has a wood roof

  34. #50 by BSivaramakrishnareddy on April 26, 2016 - 3:24 pm

    24’x42′ slab I provide 10 columns size 9″ x18″ ,required three floors ,soil is sand, footing is done 6’x6’x2’6″ sir I want witch size beam required ,steel requirement for beam &slab

  35. #51 by chris on April 28, 2016 - 7:04 am

    Hi,

    I am planning to build a 5m x 3m two storey house.
    Column size is 10″x10″, 4x16mm steel bar and 123 concrete mix.
    Is this safe?

    Thanks,
    Chris

  36. #52 by Armstrong on June 5, 2016 - 1:35 am

    Hi, am building a veranda and a beam of 5.2 m is required on 2 round collums each end. Y12 steel will be used for the beam and r 8 stirups at 500mm apart .is it possible?

  37. #54 by Miraflor R. Cruz on July 1, 2016 - 12:20 pm

    I find this topic very helpful.

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