RE: BENDING STRESS VALUE IN STAAD ?

To know the bending stress at any specific fiber location along the beam, you need to model your aluminum section selected from the standard aluminum table available in Staad. After analysis, go to POST-PROCESSING,->BEAM->STRESSES.

Now, if the standard section is somewhat like a special Aluminum extrusion profile then you need to model it as the GENERAL section. Once you model it as general section , its original geometric information is discarded by the program and only the 6 sectional properties like Ax, Ay,Az,Ix,Iy and Iz is retained for the analysis pupose and hence you can't select any fiber location against which the bending stress is supposed to be determined. For knowing the permissible bending stress, you need to refer to the specific design code which specifies the different permissible stress of a standard aluminum section. Currently, Only US ALUMINUM  design code is implemented in Staad which can only design the standard Aluminum section.