# Structural Engineering Ref. Manual 4th



## hp32si (Aug 27, 2009)

I must be overlooking something but in example problem 6.5 on page 6-9 2nd column 14 lines up from the bottom--It shows an Transformed moment of Inertia of 7660 in^4----I cannot get my calculations to equal that? Any help--Please---I feel real stupid right now!


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## deviationz (Aug 27, 2009)

I think it is the following:

bd^3/12 = 15.625* 15.625^3/12

2 * Ast * (d/2)^2

2 * 50.2 * (10.37/2)^2

It adds up to 7666 in^4


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## hp32si (Aug 28, 2009)

Thanks--for some reason I was using the full dim. of 10.37" and not setting the axis at the mid point between the #6 bars. I must have gone on a mental vacation!



deviationz said:


> I think it is the following:bd^3/12 = 15.625* 15.625^3/12
> 
> 2 * Ast * (d/2)^2
> 
> ...


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