Two-way bending with grating.

[WARose]

Have you ever considered two-way bending with grating? The tripping point is: you have the moment of inertia/section modulus for the direction it spans but not the other direction. Thoughts?

 

[msquared48]

No I haven't with the grating I've used as I've just worked from the manufacturer's tables to keep it simple.

If you design your own grating, perhaps so, but is the client going to want to pay for your time to do this?

Mike McCann
MMC Engineering

 

[peconsultant]

The only reason I could see doing this is because you are having making a section of grating work when considering one-direction spanning. I've designed some industrial facilities that have required some extraordinarily hefty grating and I've always been able to find a section that would work, even if I had to cut the span down to a really small number.

To echo Mike, why spend design budget on something that should take 5 minutes?

 

[WARose]

It’s some existing grating that I was trying to get to work. It’s supported on 4 sides (sometimes only 3), which prompted my question.

 

[JStephen]

For common grating, the bars are much smaller and wider spaced in the weak direction and aren't going to add much strength.

Also, the stiffness will be less in that direction, which means you can't apply flat-plate formulas to the problem.

 

[MiketheEngineer]

Stay w/ the mfg tables - that's why they provided them. If two-way worked better - they would have included it so they would be a "cheaper" design.

 

[rb1957]

why wouldn't you consider a grating as a plate with a reduced modulus ? (ie bending stiffness in both directions)

 

[ToadJones]

look at some grating, you will see why...bars arent the same in both directions.
Flat out, the stuff is made to span one direction.

 

[WARose]

Yeah, that's a good point on the cross bars JStephen (and the effect of stiffness on two-way action). Thanks.

 

[InDepth]

You could reinforce it with angle iron spanning in the main direction