Need Info on Dynamic Dampers for Floor Vibration
Need Info on Dynamic Dampers for Floor Vibration
(OP)
We just completed a report to an owner of a two-story office building where the occupants had been complaining of vibrations in the floors.
We performed some standard vibration analyses and verified that the floor was under-damped and in the unsuitable range of perceptability. We recommended stiffening the steel floor joists and in passing, made mention of the possibility of installing mechanical floor dampers within the structure. We understand these to be quite expensive and have never really used them in practice.
Now the owner is asking for info on the dampers and I'm having difficulty finding anything. Does anyone know of companies that provided dampers for floors? I'm just trying to get approximate pricing to shut the door on this option.
We performed some standard vibration analyses and verified that the floor was under-damped and in the unsuitable range of perceptability. We recommended stiffening the steel floor joists and in passing, made mention of the possibility of installing mechanical floor dampers within the structure. We understand these to be quite expensive and have never really used them in practice.
Now the owner is asking for info on the dampers and I'm having difficulty finding anything. Does anyone know of companies that provided dampers for floors? I'm just trying to get approximate pricing to shut the door on this option.






RE: Need Info on Dynamic Dampers for Floor Vibration
Good luck
RE: Need Info on Dynamic Dampers for Floor Vibration
I am back but like a schoolboy excited by a homework assignment.
Do you want to start the day with http:/www.nrc.ca/irc/practice/gen4_E.html
Thanks. IJR
RE: Need Info on Dynamic Dampers for Floor Vibration
JAE,
There was a case I had reported on about 4 years back. It was for a RC structure where one could feel vibrations due to heavy trucks passing on the adjacent road. No vibration was felt due to rythmic loads within the building.
Is your structure suffering from vibrations due to loads within the building?
Riz
RE: Need Info on Dynamic Dampers for Floor Vibration
If your floor is vibrating at frequencies higher than the 1st mode, then the system will be even more difficult to attempt to control by this method. The system would probably require a detailed FEA modal analysis, multiple dampers, and be very sensitive to changes in floor loading. For higher modes of vibration, the addition of structural damping might be more effective.
RE: Need Info on Dynamic Dampers for Floor Vibration
I checked the site you posted. I noted that they downplayed the effectiveness of tuned mass dampers. Our first inclination is to add stiffness to the steel floor joists as they contribute the most to the amplitude/frequency.
Riz - the vibrations are definitely due to foot traffic and not outside vehicle traffic. We walked around the floor and personnally experienced the shakes. Noticed that corner bays were the worst, exterior side bays also bad, and interior bays less noticable but still vibrating. The floor is only 3" (76 mm) thick and there are no partitions to speak of in the subject areas. Acoustical ceilings everywhere with cubicle squares and no floor to ceiling partitions.
butelja - your last paragraph tells me what I already suspected, that installing a tuned mass damper is difficult, provides unknown success, and would require a lot of engineering effort.
RE: Need Info on Dynamic Dampers for Floor Vibration
When you are done, will you please post your final solution here. I am fascinated by this subject
Good luck
RE: Need Info on Dynamic Dampers for Floor Vibration