Steel Section subject to combined forces & moments

[ozziz]

I have a RAIL girder sitting on top of a steel stump/pedestral which can be a closed or built up I section. This steep stump or pedestral is subjected to longitudinal, transverse, compression forces, in plane, out plane and torsional bending due to a moving and lifting machine on top of the Rail clamped to the top of the girder.

I can check the weld thickness for the pedestral required using resolution of forces. What about the plate thickness of the pedestral which can be a closed or I section?

Appreciate and thanks for advice.

 

[csd72]

You need to resolve everything into longitudinal and shear stress and then check the capacity of the plate to the steel code.

Torsion is resolved into a force couple located at the top and bottom flanges. This results in additional shear and bending stress.

You then need to check the overall member capacities against the same actions.

csd

 

[ozziz]

CSD,
Thanks.

But I need a bit further than what you mentioned. It is like checking the size of the weld? Do I have to resolve all the forces and moments into shear and bending Stresses in relation to the major and minor axis and compare to 0.9Fy just like weld design? If I use the Code, it just uses the Combined Stress - Bending stress about major axis and vertical Only. What about the sevtion which is subject to complex stress?

 

[csd72]

To check the section, you resolve verything into stresses and then check the maximum compression and tension combined with the relevant shear.

Then you need to check the combined shear, bending, torsion, compression capacity of the whole member in relation to the code member capacities.

No different to a normal column/beam really only more complicated.

csd

I would suggest you look at

http://www.steeltips.org/