Vibration Analysis AISC DG 11 V/S VC-A, VC-B etc

[marinaman]

I'm getting ready to design a building with a structural steel composite floor system. In my preliminary work, I've defined the column grid and have knocked in some preliminary beams and girders, just to get a feel for depths, sizes, etc etc

I went thru the AISC design guide 11 and calculated the floor's frequency at about 5.7Hz.

During the early stages of design, I find from the architect that the floor may support labs and the labs may have a vibration requirement different than that of AISC DG11. He's brought in a lab consultant who's using terms like VC-A, VC-B and such. I've just started doing research on what he's talking about.

I've been designing buildings for 25 years and nobody has ever talked about VC-A, VC-B and the like. I'm just now trying to learn how this correlates with the AISC design guide and the Thomas Murray vibration methods that I am familiar with and have used for many years.

Can anyone out there discuss the VC-A, VC-B data....or point me to a good source where I can read and learn about what this is?

Thank You!

 

[WillisV]

That's Vibration Class A, etc. See the "Design for Sensitive Equipment" chapter of DG11. You will find that the vibration requirements for lab buildings are much more onerous that typical human occupancy. Note that DG11 has very recently published a second edition.

 

[WARose]

Mr.WillisV is quite correct. By the way, a word to the wise here: be careful on running with what you come out with as far as frequency and other numbers from that design guide. Unless your system can be reduced to a very simplified system......that may not be an accurate picture. I've always had a FEA model as a back up.