Should a vibrating screen on springs be considered for Seismic loading

[Alan Power]

When designing a dynamically affected structure, one supporting a vibrating screen / vibrating feeder, should I consider the self weight of the screen / feeder when assessing the seismic loading condition? And if so, should I take 100% of the self-weight. Bearing in mind that the screen / feeder is mounted on springs at all four corners and is free to move in the X, Y and Z directions.

 

[Heaviside1925]

OP,
I have worked on vibrational isolation of rotating machinery before. Is the isolation system just a spring or are their polymer dampeners too?
Why I asked is because the analysis I was involved with looked at the frequency response of the spring-mass-dampener (spring and bushing) system to match that of the machine's frequencies. You are looking at the reverse. So, I would consider that if you are unable to analyze the response of the seismic waves through to same system to the vibra-screen, then you would be unable to remove it from consideration of the dynamic response. I am not sure if it is required but I would think there would be a possibility of putting the vibra-screen in resonance which would make the dynamic loading that much worse. Hopefully the SE's will pop on here and point you to a standard but that's my two cents on the subject.

 

[Alan Power]

The Screen / feeder is mounted on springs only, the springs will typically have their own natural frequency around 3-6 Hz and the screen / feeder is running at 16Hz. the screen has a self-weight of around 70kN. The frequency response of the structure is a separate issue to the seismic design condition. I would have thought that because the screen / feeder is mounted on springs then either the entire self-weight, or at least a portion, could be excluded from the seismic design. I have note seen this delt with in a seismic code before, thus my question.

 

[horacio Torres]

I wouldn't be considered in the design

goracio

linkedin.com/in/horacio-torres-molina-429a7b1b