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I-beam specifications calculation Question
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Posted by: mv8167

04/02/2004, 20:47:25

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I am looking for a calculator to determine the maximum theoretical load of an I-Beam. Presently, the I-beam is 16 feet long and supporting the floor above in a house with an even load. There is a support art at the 8 ft mark. Our goal is to determine if we can remove this support. So we need to now the max theoretical load we can place on we can place on this beam.


The beam dimensions are as follows.


Length: 16ft between polls

Width: 4.25

Height: 8 (od)

Thickness: 0.25

Standard home steal grade.


Can anyone give us a ruff guess-timate?


Keep rolling Mike

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Re: I-beam specifications calculation Disagree
Re: I-beam specifications calculation -- mv8167 Post Reply Top of thread Forum
Posted by: rkazanjy

04/10/2004, 14:58:08

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I would recommend proceeding very carefully here.   The removal of a midspan support is a VERY serious step.

How serious depends on the loading condition; is there a point load over the support you're thinking about removing? is the beam just uniformly loaded?

Just roughly, for a uniform load situation

the deflection you have now at the mid-point of the two 8ft sections will be 8x higher for the point at which you remove the support

Example, if you have 1/4" deflection at midspan of the 8 ft sections, you will get 2" at midspan of the 16ft section; that's quite a sag!

The stress in the beam will double.

Like many (most) situations, your beam is deflection limited, even if it is not overstressed.

Plus the "upstairs" floor (if one exists) will get a lot more bouncy; the new beam stiffness will be 1/8 of the current situation. What does the beam support? How much floor area upstairs?

Rough estimate; total allowable distributed load about 6,000 lbs.  Not considering torsional stability of beam.

Sixteen feet is a little far for a "light" 8" beam.  Have a local engineer to take a look at the situation.

IMHO just removing the beam is going to create a situation that will generate problems downstream, the support is there for a reason.




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