Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Vibration analysis using AISC Design Guide 11 when supported on walls

Status
Not open for further replies.

sponton

Structural
Nov 11, 2014
139
Anybody has any idea how to calculate the acceleration of a Composite steel deck supported by joists that at the same time are supported on CMU or Reinforced concrete walls?

It's not taken into consideration in the Design Guide examples and I don't know if assuming the wall is a deep beam would be permissible or if in any case it'd either reduce the accelerations to a permissible level. Murray's software supposedly does take into account the walls but the Design guide doesn't really mention it. I'm trying to write a program in python to carry out this automatically (based on floorvibe, with a similar GUI)and drawing information directly from AISC shape and Joist institute's database.

ANyhoo, I hope somebody can point me in the right direction, thanks !!!
 
Replies continue below

Recommended for you

In the case of wall supports or other very stiff members, they are assumed to have an a/g = 0. You would check the vibration of the system for the joist mode only and would not need to check the girder or combined joist/girder modes.
 
Oh I see, thanks for your prompt reply and I have another questions for you :). When it comes to the damping coefficient am I permitted to augment the limit above 5% or just set the value at the limit (I would assume presence of walls would be somewhat effective in damping vibrations)? I mention this because of the building I was working on earlier, I had some software by Murray that was based on the old provisions where the heel-drop acceleration was the one to rule but augmenting the weight of the floor, augmenting c. to c. distances of joists was just not cutting it, I'd end up with really deep and heavy floor systems. I just read an article by Murray and he said that they old provisions were really off and designs should be using the new provisions but his software it's not really simple to use, I think it is best when it's used in conjunction with RAM. So I'm testing my luck to see if I can create something more useful and easier to use.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor