Floor Vibration - Sharpening the Pencil for In-Situ Furnishings

[FoxSE14]

Hello,

Hypothetical floor system is 30'x30' bay comprised of WF girders supporting K-series OWSJ joists and conc slab. Suppose a heavy countertop weighing 1,000 lbs will be located in one quadrant of the bay. After the traditional first pass through DG 11 methods via spreadsheet or floorvibe, what would be your favorite program/method to sharpen the pencil and determine whether or not the countertop and cabinet system is helping out and actually acting as a mass damper? SAP2000? ETabs? Something else that handles OWSJ?

 

[jayrod12]

Sorry for asking, but why do you need to check vibration now? If this is an existing floor system, then it's likely been sized appropriately. If it's new, just telll the joist designer what MOI you need for the joists to work.

 

[BridgeSmith]

Unless that countertop is expected to be in that same location for the life of the structure, I wouldn't recommend counting on it for damping effects.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[FoxSE14]

Residential building remodel - after discussing options, and sharing the same concerns as BridgeSmith, Owner would like us to evaluate the effect of the large countertop/island prior to his spending money on reinforcement/tuned mass dampers.

Before we begin, just curious what software/tools others out there would consider using to accomplish this task? This would be a bit different than a spreadsheet calc, as we are interested in the effects of a concentrated DL/LL in only one quadrant of the bay. Anyone performed a similar check before? Favorite software for this?

 

[Aesur]

@FoxSE14, first off I wanted to say I am happy to see you looking at and considering floor vibration, I have seen far too many existing properties and new projects not considering this. This is one of the areas that the academic community has screwed us on by fine tuning beam sizes such that there is no weight for dampening effects (creating more work for engineers). I personally use FloorVibe, which includes steel joists. The steel joist manufacturers can also do this check for you. If I recall correctly one of the people who developed FloorVibe now works for Vulcraft doing vibration analysis.

As for the dampening considering the weight of the countertop, I would not use it for the same reasons above. If you were to use it, make sure you get something in writing limiting your liability should they remove the countertop and start having issues.