Floating Columns - Usage and Benefits

A floating column belongs to a vertical member that transmits the load from beam to another beam. Rather than transmitting the load to the foundation, a floating column transmits the load on to the beam.

The beam upon which the floating column stands, transmits the load to the columns underneath. The load is transmitted in the form of a point load. Here the beam functions as a foundation. This beam is known as transfer beam.

It is commonly used in high storied buildings for both commercial and residential purpose. The floating column facilitates to modify the plan of the top floors according to our need. The transfer beam that provides support to the floating column is designed with more reinforcement.

It is recommended to take special care to the transfer girders and column underneath the floating column while setting up the floating column. These beams and column should contain adequate strength to bear the load from floating column and transfer it to foundation level.

The floating columns have good strength to bear gravity loading but transfer girder must be of enough dimensions (Stiffness) with very minimum deflection.

Usages of floating columns

Now-a-days, each multi-storey building needs sufficient open spaces for parking, lobbies, conference hall, banquet hall etc. Therefore, there should be sufficient spaces in ground floor without erecting the columns in between. Generally, the columns are narrowly spaced and these are not recommended in ground floors. To get rid of the problem, discontinuity in the columns is necessary. Here, lies the importance of the floating columns.

Also Read: Importance of offset bent longitudinal reinforcement in columns

Benefits of Floating Column

1. The main objective of the floating column is to attain the architectural requirements of a structure. The floating columns are mostly effective in case the lower floor contains a large span hall with rooms constructed on its upper floor like hotel, auditorium etc.

2. They can be used for building up soft storeys.

3. The plan on each floor can be altered easily.

4. The rooms can be separated and some sections can be elevated devoid of uplifting the entire area.

Disadvantages of Floating Columns

1. The lateral forces caused by earthquake should be transmitted to the foundation via clear force transfer path. This force transfer path is interrupted in case of floating columns. These floating columns draw a lot of seismic force, that can create adverse effect in high seismic zone.

2. The floating columns is useful for only vertical forces. But they are not recommended for lateral forces like earthquake. The floating columns should not be provided in high seismic zone regions.

3. It raises the storey displacement in buildings.

4. Since the column does not stand on primary continuous columns, discontinuity occurs with the columns situated underneath and above which make it insecure.