Design - Steel Plate Loading
Design - Steel Plate Loading
(OP)
Hi to all,
I have a rectangular plate sitting on two parallel beams (I) which are sitting on subgrade. I'm looking at bending moments in rectangle plates (Civil Engineering Handbook 2nd Edition); some of the systems appear to resemble this concept though all equation appear to solve for ,w, (Deflection of Plate).
Any ideas on the best way to work out the maximum load for this system?
Thanks
Swaiteen
I have a rectangular plate sitting on two parallel beams (I) which are sitting on subgrade. I'm looking at bending moments in rectangle plates (Civil Engineering Handbook 2nd Edition); some of the systems appear to resemble this concept though all equation appear to solve for ,w, (Deflection of Plate).
Any ideas on the best way to work out the maximum load for this system?
Thanks
Swaiteen






RE: Design - Steel Plate Loading
RE: Design - Steel Plate Loading
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Design - Steel Plate Loading
I simplified the problem to a rectangular plate supported at the boundaries.
Mild Steel(E=200GPa)(650x1100x8mm)
Plate loaded uniformly (qo)
Using the governing differential equation I solved for Deflection (w).
Under load of 1000kg: w = 4.47mm
Under load of 10000kg: w = 48.56mm
For a plate of the above dimensions this appears to be practical. What do you think?
In an attempt to include the other elements in the original system I am looking at the (I) beam supports. What can I do to calculate the maximum load of an (I) beam; or shear strength of the flanges of the (I) beam? Or what do think the capacity of an (I) beam (100x50x8mm) would be?
Thanks
RE: Design - Steel Plate Loading
Also if you know the defelction work with that. pg 3-7 in 13th edition gives formula for max deflection. Even then you might still get complaints that the floor is moving.
RE: Design - Steel Plate Loading
If it's supported on all four sides, then the normal bending stress derivations assume that deflections are small, not more than half the thickness or so. If deflections are over this, it doesn't mean the plae is inadequate, just that the analysis isn't valid anymore, as the plate starts developing in-plane stresses rather than bending stresses.
With it not being too clear on how the plate is supported, it's also unclear how the I-beams are loaded. If they have uniform load above and uniform support below, there isn't any significant bending, at least not in the beam sense.
RE: Design - Steel Plate Loading
You really have to define and explain your problem much better than you have if you want any meaningful help on it, you shouldn’t expect us to keep guessing. Show some sketches, dimensions, sizes and loads so we can get a sense of the proportions and the real problem. What are the soils conditions, Mike M’s assumption of a beam on an elastic foundation sounds about right to me. But, is it two beams side by side and fixed to each other in some way, with one load from above and at the center of the beam length, or what? Or, are the beams separated by some significant amount, and the plate spanning btwn. them? That 48.6mm of plate deflections sound pretty high to me whatever equations you used. That sounds like a whole week’s worth of deflection to me.
RE: Design - Steel Plate Loading
I uploaded drawings of the problem. plate (1300x840x8mm), Rectangle in between I beams (1100x650mm), I beams (50x100x8mm).
Assuming the I beams are sitting on high strength concrete. What is the max load for this system? Or what is the deflection under central point loading?
I don't want the problem solved for me just point me in the right direction.
Thank you
RE: Design - Steel Plate Loading
You may consider getting a copy of roark's formula's for stress and strain. Should give you all your answers.
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RE: Design - Steel Plate Loading
2 things:
1)Find out the allowed ground pressure for your concrete.
2)The reason most of the formulas you find are solving to deflection is because it's usually the defining factor. You'll reach an unwanted deflection before you'll reach the tensile strength limit. This may not be true in your case however, so you'll have to calculate both.
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Nvidia Quadro 2000
RE: Design - Steel Plate Loading
For the I-beams, you can check the webs treating thems as short columns. If there's any possibility of lateral loading, that might control the design.