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Floor Joist Analysis

Floor Joist Analysis

Floor Joist Analysis

(OP)
I have a simply supported Douglas Fir floor joist that has a simply supported, 16-foot span. I am getting too much deflection in the center of this span. I have enough room to add an 8-foot long steel flitch plate in the center of the span. Could someone help me in how to calculate the stresses/deflections in this composite beam?

RE: Floor Joist Analysis

Slide rule era's link gets him part of the way there.  Foamguy, you'll have to calculate your stresses the hard way since your stiffness changes along your beam.  Take a shot at it and if you can't get it (and I have time today), I'll give you some pointers.


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RE: Floor Joist Analysis

(OP)
Thanks swearingen. I've been away from beam analysis for about twenty years. Analyzing a simply supported, standard beam is simple enough, but one that has a different cross section and higher stiffness for the middle eight feet is beyond my abilities. Any help you can provide would be much appreciated.

RE: Floor Joist Analysis

It turned out that it's pretty involved, so I banged it out last night - I checked it and it was wrong, so I've got it in the hands of one of our young engineers to find the little negative sign I missed somewhere...


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RE: Floor Joist Analysis

(OP)
Thanks again, swearingen. Let me know if the young guys figure it out. I was thinking that it could be solved by analyzing the wood and the metal beams separately and then combining the results by superposition, but it became pretty tricky.

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