Deformed crane girder

[ASFI]

a crane girder made of welded plates was accidently dropped during manufacturing and it was deformed in the lateral direction. in other words it now has like a camber affecting the bottom and top flanges laterally. it is like a permanent lateral deflection...

it is still good for serviceability, it will not affect the hoist running on its bottom flange.

however how do we define if it is still good structurally?
we have made some welding tests and it was OK.
what about other factors that need to be considered?

thanks for your help

 

[hokie66]

I don't think it is possible to cause a uniformly deformed structural member by dropping it. How much sweep do you have? I imagine it was done because the welding process was not controlled adequately. There should be no reason to accept a new crane girder which is not within specified tolerances.

 

[JAE]

A structural engineer would have to measure the horizontal sweep and then, within the context of the entire bridge assembly, determine if the actual sweep induces significant second order effects that compromise the crane's strength and long-term serviceability.

or - shorter version:

Hire a structural engineer to tell you.

 

[corus]

An other factor worth considering is that you have induced some residual stresses into the stucture as you have taken it beyond yield to produce permanent deformation. This will affect the fatigue life of the structure. Essentially, it may look ok, but it might not last long.

Tata

 

[paddingtongreen]

Most codes of practice have tolerance limits, including sweep.
If the sweep is greater than the permitted tolerance, it will introduce a torsional load that was not in the original design, then you need to straighten it or have a structural engineer check the design for it.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[a2mfk]

Agree with Paddington, my main concern would be unintended torsional loading if the vertical reaction is outside the longitudinal axis of the support girder.

 

[BAretired]

The beam should be straightened to within acceptable tolerance.

BA