Frequency analysis of a staircase.

mmartin

Good morning to everyone:

I enclose you a frequency analysis of a reinforced concrete staircase.
You will notice that the first vibrational mode (mode 1) is 42Hz which is far away from >8Hz which is the top human perception limit(annoing limit).

About the files attached:

• The 3d model was done using FREECAD 0.19.(the rar file contains the FCStd file)
  
• The analysis was done using MECWAY 13.0+ CCX 2.17 built-in.
  

I also want to tell you that this is a preliminary analysis just to know the frequency ranges of the staircase almost without load (only self load and a fraction of the live load). In my case, to know mode 1>=8Hz is enough to realise that the stairs are suitable.

Best regards


MANUEL

mmartin

Victor

Thanks for posting that. I guess this shows a need for a proper distributed surface mass. What does that mass represent?

mmartin

Good morning VICTOR:
Actually the 3D model includes a distributed mass over the top of the slab representing:
First: the dead load from the steps
Second: from 10-20% of the life load.

MANUEL