Vibration analysis of Concrete Joists
Vibration analysis of Concrete Joists
(OP)
I have a project with one way wide module concrete joists that is going to be used for a laboratory and it has strict vibration criteria. The only design guides that I can find for vibration are for steel. Does anyone have a method for determining the vibration of a concrete floor system?






RE: Vibration analysis of Concrete Joists
RE: Vibration analysis of Concrete Joists
With judgment, you can use the AISC DG11 or SCI simplified procedures, but more elaborate analyses might be called for here.
RE: Vibration analysis of Concrete Joists
The SCI elaborate procedure accounts for this. They have one way for low frequency floors and one way for high frequency floors.
RE: Vibration analysis of Concrete Joists
If following the AISC DG procedure, be careful to use appropriate, acceptable frequencies.
I had some literature for wood that recommended the natural frequencies be in the 22-25 hz range, which differs significantly from the steel recommendations.
I can imagine concrete would have different recommendations.
RE: Vibration analysis of Concrete Joists
There are ranges of walking frequencies. Perhaps that's what you're thinking about. People only usually walk between about 1.6 Hz (96 bpm) and 2.2 Hz (132 bpm).
Wood is a completely different ballgame. If anybody needs them at some point, I can provide refs to several good papers.
RE: Vibration analysis of Concrete Joists
I did find a new guide developed by Arup that was published in England in January 2007, " A design Guide for footfall Induced Vibration of Structures". I am still going through this guide, but their method for a high frequency structure using FE analysis requires using the modal mass in conjuction with the walking frequency and the structure's frequency. Their FE program gives them the modal mass for each mode, but I am using Risa 3D and I would have to manually calculate the modal mass from the mode shapes which would take some time.
RE: Vibration analysis of Concrete Joists
I would love to see the papers you have for vibrations (wood or whatever else you have).
I am sure you are right about the DG11, but I swear I remember some natural frequency limits in the 6-8 hz range depending on application (dancing, dining, office floor, etc..), in addition to acceleration limits.
RE: Vibration analysis of Concrete Joists
RE: Vibration analysis of Concrete Joists
RE: Vibration analysis of Concrete Joists
RE: Vibration analysis of Concrete Joists