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. Of-course 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.

You can hire me for your structural design need. Contact me.

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 12” (225mm x 300mm) with 4 bars of 12 MM Fe415 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

102 thoughts on “Thumb rules for designing a Column layout | Civil Engineering”

  1. slabs load come on beam than total load come on column ?
    how to do calculation for reinforcemnt
    pls let me know as soon as possible
    thank you

    venka :
    slabs load come on beam than total load come on column ?
    how to do calculation for reinforcemnt
    pls let me know as soon as possible
    thank you

  2. hey… this post is really helpful, thanks. Sir, i need to know what dimension of columns are used in a 15 to 20 storey building and also the span between the two columns.

    • The maximum I have designed is Basement+Ground+10 floors. My largest column was 18″ X 30″, M25 Concrete. The four spans were 18′, 14′, 26′ and 14′.

      Larger structures are a lot more complicated. Newer construction techniques have really helped. I have seen columns of only 9″ thickness, but 12 feet in length in 30+ storey buildings. Mivan formwork technology is being used on a large scale for residential towers. Post-tensioning structures are preferred for commercial and office buildings. Really way above my skill level.

  3. Please, we want to start a single story with gallery church auditorium with a capacity of 1500 congregation. kindly advice on the appropriate column and foundation size

    • Hi Daniel
      Where are you based?
      The column and beam design really depends on the floor plans and elevations. Let me know if you are interested in getting it professionally designed.

  4. It’s very useful for me…and I also have one doubt …I use 2 nos of 12mm at top and 2 nos of 12 mm at bottom and 2 nos of 10 mm at cent of the beam ….the beam size is 1 feet depth and 9″ breath…the span of beam length is 16′ it will take load or not…

    • Hi Arun,

      It will depend what is resting on it. How big a structure is it?
      How many columns and beams are there? number of storeys (floors)?

  5. Hi
    1) My plot size is 24′ X 49″, and I am planning to construct G+2+Pent House, my engineer planned 11 columns, i.e four C1 (9″ X 12″), with 16mm 6 bars + 12mm 2bars, four C2 (9″ X 12″), with 16mm 4 bars + 12mm 2 bars and Three C3 (9″ X 9″), with 12mm 6 bars. Distance between C1 is 15′ in all sides, C1 to C2 is 15′, C2 to C2 is 10′, Distance between C1 to C3 is 6′, C2 to C3 is 10′

    (This is not distance, column points)
    Columns points fr South West:2′(C1),17′(C1), 32′(C2),43(C2)
    Columns points from South .:2′(C1), 17′ (C1), 32′(C2), 43(C2)
    Columns points from East South 2′ (C3), 32′(C3), 43(C3)

    Columns points from West to South East:2’16’ 22′ (1st Line)
    Columns points from West to East: 2’16’ (2nd Line)
    Columns points from West to East: 2’12’22 (3rd Line)
    Columns points from West to Noth East: 2’12’22 (4th Line)

    My structural engineer is just started his consultancy, I would like reconfirm the strengths. Please help me.

    Please advise

    • The steel is decent but my recommendation would be to increase C1 size to 9” x 18” on ground floor, 9” x 15” on first floor , 9”x12” on second floor and above.
      C2 should be 9”x15” on ground floor, 9”x12” on first floor and above
      C3 should be 9”x12” minimum on all floors.
      Remember to use M20 grade concrete and FE500 steel.

  6. Question 1:>My question is when I use a column size of 10″X12″ using four 16 mm bars for a G+2 residential house ->What is the distance between the centre of the two columns that should not be exceeded ?
    Questio2:>Also please let me know the maximum distance between the two columns that should not be exceeded when I use 12″X18″ column sizes with six 16 mm bars for a G+2 residential house.
    Please advise.

    • I wish it was as simple as that Prashant. There is a need for the surveying of the site prior to making calculations for foundations, columns and beams of the building. There is not a set way of doing a column design. I would recommend that you get it designed by a certified Structural Engineer.

  7. dear sir.
    my site is 16 feet frontage and 116 feet stretch.i wanna know what will be the column details.if i place 9”x12” with the distance of 10 feet is acceptable or not.

  8. Dear sir
    I want make a 3 story building of 2540 sq.feet.So I want to know the column to column distance,size,tmt bar, concrete grade etc.

    • Hello Ashed,

      This website is only for information purposes. You must employ a certified Civil engineer for any building works. It is unwise to be doing it yourself.

      • slabs load come on beam than total load come on column ?
        how to do calculation for reinforcemnt
        pls let me know as soon as possible
        thank you

    • Hi Ramya,

      There is no thumb rule for minimum or maximum distances. It all depends on the layout of the building and how cleverly an engineer is able to design it to maximise its functionality.

      • I need a column to be designed for a span of 8 Mts and the size of room is 25feet x 68 feet I need the columns only on the sides I don’t need Columns in the center and beam size also .

  9. If a plot of ground floor is constructed with 6 by 12 pillar. It is provided with 15 pillars. Can I suggest somethings to the client so that he can comfortably construct first and second floors,

    • We have a paid service where we do provide every kind of layout. Let me know if that is of interest to you and I shall forward the details.

  10. 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?

    • Hi there,
      I would not be able to answer that question as it would me be giving wrong advice. We run a professional civil engineering service where we offer advise (paid). Please email arjaved@gmail.com with you queries and we will take you from there.

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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??

  16. 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.

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

  18. 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.

    • 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.

  19. 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

    • 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.

  20. 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

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

  22. 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

    • 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.


      Architectural and Structural Design Services by Civil Projects Online

      Look forward to hearing from you.
      Regards,
      BenzuJK

  23. 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

  24. 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.

  25. 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?

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

  27. 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.

    • 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

  28. 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

  29. 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

    • 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.

    • 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

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.