Calculating load on steel grating
Calculating load on steel grating
(OP)
My company has been contracted to install a fire sprinkler system in a generating plant with steel grated mezzanines. We would like to be able to use drivable scissor lifts on the grating, but are unsure if the grating is suitable. The customer has informed us the grating has a 150lb/sq.ft capacity, and I assume this is "live load" as nothing else (machinery, pumps, etc) is supported by the grating. The lift weighs 2,400lbs. If we were to put plywood down over the grating, would it distribute the weight enough? How do we determine how much plywood is needed, i.e. one ¾" layer, two? Thanks in advance for the replies.






RE: Calculating load on steel grating
RE: Calculating load on steel grating
Since the steel grate is much stiffer than plywood, I think the plywood would do little more than spread out the tire loads a few more square inches than if it were not there at all.
RE: Calculating load on steel grating
You should probably bring a structural engineer in to take a quick look at it. If it's okay it shouldn't take long to confirm it.
2400lbs isn't a huge amount when you're presumably dealing with steel, but it could still end up overloading light platform framing, especially once you add in a couple of people and equipment
RE: Calculating load on steel grating
Also - if it is much older than 5 years or subject to noxious environment - you may find a lot of rust and/or deterioration.
Had a situation recently where some steel was practically gone after 18 months!! and people work right there!
RE: Calculating load on steel grating
BA
RE: Calculating load on steel grating
I have put down steel plate to gain extra bars when needed. I doubt plywood would do much good at all.
RE: Calculating load on steel grating
The allowable uniform loading is not really all that helpful, and you should check this for yourself anyway. Most bar grating is pretty similar, so you can find many different sources that will show you the allowable loading. All you need to do is measure a couple of things:
1. Grating depth
2. Bar thickness. 3/16" bars and 1/4" bars are pretty common.
3. Bar Spacing. 1"/2"....
4. Grating span
5. Transverse bar spacing.
From this you should be able to figure out what grating type you have. You need to check the allowable concentrated loading for your profile. Here is a link to a McMaster page. There are many others too.
http://www.mcmaster.com/#6849tac/=av121c
I doubt the plywood will do anything, but protect the wheels. The grating is likely far stiffer, so the little bit of wood will not help to increase the overall strength much. Steel plate can help in some cases, but is not always effective. You could always buy a few pieces of new grate designed for your machine.
Brad