Holdfast Training Services Trial Blog

Since starting my Phase 3 attachment with Robert Bird Group last week I have been tasked with evaluating the current conceptual design of a 70 storey building.  The main effort in this exercise was to see if the column layout could be revised to maximise floor space in the upper floors.  An impression of the structure is in the figure below.

The current design sees a consistent column layout between Ground Floor and Level 53.  Above Level 53, the layout changes to maximise floor space in the upper levels.  My task was to evaluate whether the Level 53 transfer beams, would still work if they were moved to Level 47, without changing their geometry. The main consideration here is the additional load on the transfer beams caused by Levels 47 to 53.  An illustration showing the approximate location of the transfer beams is in the figure below.

A plan of the structure is below.  The two transfer beams have been highlighted.

A simple sketch indicating the loads acting on one of the two beams is below.  There are three columns acting as point loads on the beam, with five supports below the beam.  Moving the beam lower in the structure simply changes the magnitude of the loads.

Once I understood the intent, I set about analysing the loads.  I captured the loads acting on each floor and multiplied them by the area of that floor being supported by the columns in question. This allowed me to work out the magnitude of the point loads acting on the beam.  An example of my load analysis for one of the columns is below.

I then added the UDL acting on the beam and checked to see if the beam could perform under the new design loads.  This check was performed using a software package, commonly used by Robert Bird Group – ‘RAPT’.  RAPT is not too dissimilar to STAAD Pro.

After running the check, I was able to confirm that the transfer beams could continue to perform as designed, without changing their geometry.

A relatively simple task, ideal for dusting off the Structural Analysis notes.