ETABS_ 1

It's always good to read about the works and words of the people before us. And I come across lots of writings which suggests the importance of hand/manual calculations to cross verify the results by a software. It usually goes like this : " Whenever I ask a beginner/trainee whether he checked it manually, their answer is usually NO". Manual calculations are a must, but if it's just a calculation, what better than a computer. So it's more important to understand how the software works and gives the results of an analysis/design.

ETABS is a software by CSI. It is an integrated software for the structural analysis and design of buildings. It is like an standard in the construction industry. But it is a tool, which gives the results as per the input and it should not be taken at a face value.


This series will be updated as per my experience and discovery of the working of the ETABS software. There are manuals for its working for sure. But what good is a manual if you don't understand and use it.

Recently I had to check the shear capacity of Beams on a building and increase its dimension for the design. Understand Shear as a reaction which will resist the cutting of a section parallel to its cross section. Imagine cutting butter and a bread, the butter will be sliced easily which indicates it has lesser shear resistance. 

S = Shear Force


Now a Reinforced Concrete Beam resists shear through its Concrete and the Reinforcement provided. 

As per ETABS, the Concrete Shear Capacity is given by:

The capacity depends on the grade of Concrete, the width and depth of the beam. As you can see, a beam has certain capacity and can resist only as much. The rest is taken by the reinforcement.

As per ETABS, the required Shear Reinforcement:



As you can see, it depends mainly on the dimensions of a beam, the bw and d in the equation. 

I sought out to merge the gap between the increasing of a single beam or to distribute the load and increase the beams connected to it. Turns out, the load distribution was not very significant in my case and I had to increase the beam depth.

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