NCEES Str-II Sample Questions and Solutions, Building problem 450

[Jack1977]

In Building Problem 450, Design Data says the RoofLL (Snow) = 30psf, then in the solution, load combination should be either 1.2D+1.0E+0.5L (when take it as live load) or 1.2D+1.0E+0.2S (when take it as Snow load). Why in the NCEES's solution load combination uses 1.2D+1.0E+1.0L? I can't understand it. Can anybody help me with this?

Thanks.

 

[McEngr]

In Building Problem 450, Design Data says the RoofLL (Snow) = 30psf, then in the solution, load combination should be either 1.2D+1.0E+0.5L (when take it as live load) or 1.2D+1.0E+0.2S (when take it as Snow load). Why in the NCEES's solution load combination uses 1.2D+1.0E+1.0L? I can't understand it. Can anybody help me with this?
Thanks.

There should be an errata for this problem. 1.2D+1.0E+0.2S is the correct combination I believe.

 

[Jack1977]

Same Building probelm 450, another place.

in sizing the area of footing, NCEES's solution assume 5'x5'square footing, with an eccentricity e=1', it gives the maximum soil bearing pressure fb:

fb=2R/(4)(4.5), is it another mistake?

To me it should be:

fb=2R/(5)(4.5)

if it is another mistake, then they didn't corrected it in the errata, they need a 2nd version of errata for both above mistakes.

Am I right?

Thanks?