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 Posted by: DavidH ® 12/08/2006, 21:25:55 Author Profile eMail author Edit I have got a bit of a problem understanding the calculation of this. Can somebody give me some help.

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 Re: Moment of Inertia Re: Moment of Inertia -- DavidH Post Reply Top of thread Forum
 Posted by: hjens56 ® 12/12/2006, 15:15:38 Author Profile eMail author Edit Need a little more info about what you don't understand.

 Re: Re: Moment of Inertia Re: Re: Moment of Inertia -- hjens56 Post Reply Top of thread Forum
 Posted by: DavidH ® 12/12/2006, 22:06:18 Author Profile eMail author Edit Well if for instance we use the wide flange charts from AISC for a W21 x 62 beam, 21"x62lb the Inertia for that is 1330 and when I use the formula for that beam 20.99 d, 8.24 w, .615tf, & .400tw than I come up with a different figure using the formula bd^3 - h^3(b-t) / 12. How come?

 Re: Re: Re: Moment of Inertia Re: Re: Re: Moment of Inertia -- DavidH Post Reply Top of thread Forum
 Posted by: Kelly Bramble ® 12/13/2006, 10:27:43 Author Profile eMail author Edit A W flange has radii at all surface intersections and corners I beleive. So, manually calculating is only a estimation (though probably good enough). If you realy use the AISC W21 x 62 beam (specify in your material block) I would use the AISC number. Also, be sure your are using the same Ixx, Iyy, or Izz. Related: Modified by Kelly Bramble at Wed, Dec 13, 2006, 10:30:26

 Re: Re: Re: Moment of Inertia Re: Re: Re: Moment of Inertia -- DavidH Post Reply Top of thread Forum