Bridge Grating in STAAD.Pro

[Bill2001]

Hi dear STAAD.Pro experts!
It will be great if anyone can help me on the following problem:
I'm trying to model a bridge shown in the attached file.
The bridge construction has 2xHE1000B as main beams (24 m) with centre line 3.6 m and transverse beams with centre line 1 m.
The bridge deck is of steel grating 80 mm thick.

1) Is there a way to model the steel grating. The problem is that I can't use FE meshing to
generate plate elements because grating is not massive.

2) Is there a way to place the wheel loads in the mid span as shown 0.5 m from guard rail?

Please adivce!

Best regards
Bill

 

[edward1]

I would find or calculate the moments of inertia of the grating in the two principal directions and calculate the equivalent steel plate thickness from I= 1/12 bh^3. Then you can use this equivalent plate in your model. However, from my experience, this steel bridge grating does not perform well or last long under heavy truck loads.I would use reinforced concrete deck with a minimum thickness of 8" for this design. Also, there are only two (2) main girders-no redundancy;if one girder fails, the bridge fails.

 

[Bill2001]

Dear Edward1,
Thanks, would you please confirm this assertion?
If I get you right you mean:
Hz=(12.Iz/b)^1/3 (Strong axis)
Hy=(12.Iy/b)^1/3 (Weak axis)

Average height h=0.5*(Hz+Hy)

Is this correct?
Bill

 

[edward1]

Bill,
That is correct.
Ed