Part-2: Column layout plan

Before start reading this article i suggest to read previous article which is about some basic design consideration according to IS : 456: 2000.

The size of the column is depends upon the some condition such as load, height, material, earthquake, etc.

Some of the thumb rules are available for design the columns, which is only applicable for the small house structure design.

The minimum size we can use for column is 9 X 9 inch.

Thumb rule says for G+1 story house, use 9 X 12 inch column with M20 grade of concrete and Fe 415 grade steel.

But, in our case, we will analyse the whole structure so we will decide the column size according to the software results.

Architectural drawing

Before deciding the size of column, location of the column, orientation of the column, let's check the architectural plan.

Ground floor architectural plan

The total area of ground floor is 24 X 36 feet. which consist, one master bed room, living room, otta and parking and two toilets.

The outer walls are 9 inch thick and inner walls are 4.5 inch thick. the design is not much symmetrical in both the direction.

let's study the first floor plan.

First floor architectural plan

The first floor is extended from 24 feet to 27 feet at the front side of the house.

Second floor architectural plan

Only inner arrangements is changed in the second floor plan.

Terrace architectural plan

Cabin plan

The terrace and cabin also given for understanding the plan.

Preparing the column layout plan

The role of structure designer is to provide the stability to the structure with maintaining a good aesthetic view.

Generally, the outer thickness of wall is 9 inch and the inner thickness of wall is 4.5 inch.

So, 9 inch thick columns and beams are mostly used to kept the better appearance of the house. Although, 12 inch thick column and beams will show better result as compared to 9 inch thickness of a members.

As outer wall thickness is 9 inch, the 9 X 18 column will covered by plastering and paint, So the required architectural appearance will be maintained.

Now, we are set for placing the column.

Outer columns

Firstly, place the outer column. we are designing of two-story house so we will choose the minimum size of 9 X 18 inch for column.

Remember one thing, always choose higher size of column instead of higher size of beam.

Outer columns

First step is to draw center-line plan according to the arrangements of the walls. you can use notebook or software.

I recommend use the cad software to make center-line plan to reduce the time and to get accurate result.

Make sure that the distance between columns must be within 5 to 18 feet for achieving the limiting size of columns.

For example, if the distance between two columns is 20 feet or more then the size of resisting members will increase and design could go under a heavy design.

Make the design lighter as much as possible. because, for two-story building we should not have columns and beams size more than 9 X 24 feet.

As shown in plan, the distance between C-1 and C-2 is 16 feet and C-2 and C-3 have 18 feet 6 inch distance.

The C-1, C-2, and C-3 will support the cantilever balcony and slabs so we should increase the size of that column. for not we just set the all column and beams.

The orientation of the columns should be done according to the walls arrangements, for example,

The C-1, C-2 and C-3 are placed vertically. if we place that horizontally then the columns can be seen inside the living which is not good for appearance of the house.

Inner columns

Now we will set the inner columns and make a column layout plan.

Column layout plan

While placing the inner columns we need to keep looking the all floor plan whether the columns are placed properly and not disturbing the other floors view and living.

For example, If we move C-2 on left side by 12 inch or more than it will disturb ground floor parking, first floor bed room and second floor family sitting.

Now the question is why i add the C-8?

The reason behind that is there is huge space between C-4, C-5, C-11 and C-12. so the load will be higher at that part and size could go higher. placing C-8 can help to reduce the size of C-4, C-5, C-11 and C-12. we will get the report of that in the analysis section.

The staircase will have high load so i recommend to place four columns enclosing the stair. you can place three column depending upon the load.

For example, in our case we can remove the C-10 which will not majorly impact on the structure.

C-11 and C-4 is not in line because there is not good arrangement of walls by architect so we can do nothing in that condition unless the architect revise the plan.

For now, we set the column size of 9 X 18 but after getting the analysis report we will modified the size of columns according to the load data and finalize the detailing.

Next step is to prepare a slab arrangement and to make beam grid plan.

If you have any questions and query, feel free to ask.