CHECKERED PLATE DESIGN

[RLC32681]

I am designing a checkered plate which is subjected to traffic. The plate is 8 mm thick and the span is 2m. In order to withstand the design load, i try to provide a stiffener but unfortunately it fails due limited depth of stiffener of 25mm. I try also to make the distances of the stiffener as close as possible but it still fail. Can anyone recommend how to design this checkered plate? Thanks in advance.

 

[SlideRuleEra]

For long spans, like the 2 meters you are considering, weld the checkered plate on top of steel bar grating that has the necessary load rating for the span. This approach is used in some industrial applications.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[RLC32681]

exactly, and i consider it as composite section in my design. it so happen that it fails because the depth of the stiffener is limited to 25 mm

 

[hokie66]

In which case, you need more depth. There may be an imposed limit, but you will have to get that limit relaxed if you can't make it work. Sounds like you have 33 mm total. Would a 33 mm solid plate work? I don't know what your traffic load is, but I did a quick calculation with 33 mm plate and came up with an allowable line load at centre span of about 70 kN/m (200 MPa stress), with 20 mm deflection. I think you are trying to put 20 pounds of .... in a 5 pound sack.

 

[JedClampett]

Your design is doomed. Your best hope is to either find something made of cast iron (hard with 2 m span)or weld some plate on some heavy duty grating (a lot deeper than 25 mm). Anything you try to fabricate runs the risk of warping and rattling.

 

[dik]

Alex's floor plate program is pretty good and I've attached a solution spreadsheet...

Dik

 

[dik]

wrong file....

Dik

 

[RLC32681]

You are right hokie, the total depth is limited 33mm. I am trying to design it with 65Kn wheel load including impact loaD. I try to check also using 33mm plate but it fails in deflection. I agree also with JedClampett that warping and rattling is a problem. I am planning to used prestressed concrete instead of steel? Any inputs guys.

Thanks also to dik for the spread sheet.

 

[hokie66]

Concrete will require a lot more depth than steel. Steel is the strongest material we structural engineers have in our arsenal. If a 33 mm steel plate gives too much deflection, and I think it does, you are stuck. Can't be done in that depth.

 

[Bobber1]

Carbon fiber material? Pretty strong, stiff stuff.