How can i do this load caeses ?

[abduallahadi526479]

Hi everyone
can anyone tell me how to do this loading condition for simple cantilever beam that shown in the picture in Robot 2012 ,
to find the worst case of positive moment for the first span and worst case for the negative moment at the support ?
f0220008.jpg

[kmarsh]

Hi,
You'll want to create 3 load cases:
DL (across whole member)
LL1(between supports)
LL2(on cantilever)

Then in automatic combinations generation dialog, on the group tab, create a group for LL1 and LL2 with an "Or(Incl)" (Inclusive OR) relationship. This will generate the following combinations of LL1 and LL2 every time live load is involved in a combination. (combination live load factor is whatever factor is applied to live load for the current combination algorithm, for example in 1.2DL+1.6LL 1.6 is the factor on Live Load)
combination live load factor*LL1
combination live load factor*LL2
combination live load factor*(LL1 + LL2)

Update: To answer your *exact* question: how do you get those, exact, two cases, you should opt for an Exclusive OR relationship "Or(excl)" which will generate:
combination live load factor*LL1
combination live load factor*LL2

I hope that helps get you on the right track. You can learn more about generating load combinations in Autodesk Robot Structural Analysis Professional - Essentials here: http://tiny.cc/RobotStructuralWLAmazon where we cover advanced grouping and relationships for generating complex load combinations.

Cheers,
-Ken

[abduallahadi526479]

Thanx a lot mr. kmarsh
it really helped