ETABS Connection Tip

One important engineering judgement you need to make in ETABS, is about connection points. As I explained several times in my video coarse in reality there is no ideal joint similarly none of the connections are completely fixed. So being joint or fixed is just a simplification assumption. To make this decision we need to decide based on relative stiffness of the connection and see in which direction it can possibly deform.

Luckily, codes and standards help use to make these decisions more realistically. However in some cases there is no specific reference and the user must decide on his own. Here is a useful tip for connection of columns to the foundation.

In ETABS, the connection of column to foundation can be assigned fixed or joint. It is totally up to the user. The main advantage of fixed connection for the base of the structure is that it reduced the displacements. But on the other hand, fixed connection requires stronger foundation, the base plate and the bolts.

Another tip is that considering fixed connection for pier footings is completely useless because they are substantially move in the ground. In other words if you want to use a pier footing for your structure always consider the connection of the column to be joint. Otherwise you waste lots of money to construct a useless fixed connection.