Components of Sub-Structure of a Building, bct4

We have considered "Sub-structure" as 3rd work phase of building construction in our tutorial series. We left a work-phase that is Ground Work. Because we discussed about that topic several times here in this blog. You can read them in following links -

6 ground works to Prepare a Land for Building Construction.
7 Preliminary Works to Do Before Starting Construction Project

Building construction tutorial, substructure

In this post we'll discuss about sub-structure of a building.

Sub Structure: The 3rd Work-Phase of Building Construction

First of all, we should know "what is sub-structure"?

"The structure below ground level can be defined as sub-structure".

Someone defined sub-structure as "the structure which can't be visible".

"The structure up to plinth level is defined as sub-structure" in many engineering books by specialists. 

From the definition of Sub-structure we can say it consists of the following parts of the building -

  • Foundation
  • Short Column
  • Grade Beam

Foundation: foundation also called base. A building completely stands on it. So it is the most important part of a building. There are many types of foundation we can make to build a building. Please see this post to know more about foundation.

Short Column: Theoretically, short columns are those which effective length to least lateral dimension ratio don't exceed 12. Generally,  A column between foundation and grade beam is called short column or neck column.

Grade beam: grade beam doesn't carry any vertical load. It just ties columns to prevent lateral movement. That's why this beam is also called Tie beam. Sometimes ground slab rest on grade beam and thus carries vertical loads. Then it is called ground beam.

Dear reader, when I started this building construction tutorial series that time I expected to publish two or three posts in a week. But I was extremely busy on some of my projects. That's why I haven't published post for a long time. I'm sorry for that. From now I'll publish regularly, at least one post of this tutorial series in a week with some other important posts.

However, we already know from this post that ground floor slab can't be included in sub-structure as the ground floor slab is visible and ground floor slab is built above the plinth level, yet someone includes ground floor slab in sub-structure if it is build on the ground.

I've discussed briefly about sub-structure in this post. I'll discuss details about each item of sub-structure later in this tutorial series. Our next post of this tutorial series will be about super structure. So subscribe by email or to get immediate update.


  1. good .you requires ,words of confidence

  2. Is the size of neck column and column in superstructure same? I mean to ask if we need to provide plastering for neck column?