twist in the beam

[Rinku12]

hi ,

The issue is a step in the monorail beam flange. The step is about 3/16" and is due to I-beam twist from the mill but its within code tolerance. See attached picture.
The hoists are going to pass over the joint with misalignment. The track running surface vertical misalignment limit is virtually zero ( as close as possible) in more restrictive codes ( CMAA ) and max 1mm in less restrictive codes (ANSI – MH27.1) .

We need to realign the surfaces to achieve the tolerances. My suggestion for the adjustment is to align them as closely as possible considering the limitations we have and then grind smooth the transition. Its a joint so I don't flexure stress due to bending in addition to local stress by wheel load. I checked this beam by CMAA SPEC 74.

I would appreciate expert opinion here.

 

[BAretired]

You asked for expert opinion, so I have hesitated until now. I have not experienced this issue myself, but your proposal is precisely what I would do.

BA

 

[JoelTXCive]

I'm not an expert, but heck that has never stopped me from chiming in...

Since it's a pinned connection, in theory you do not need the flanges. Moment stops at your connector; and the shear jumps from web-to-web via the connector.

Globally, I think you are fine.

Locally, the outstretched flange legs still need to carry the wheel load from the hoist.

I think you could check the flexural capacity of the reduced section on the outstretched flange leg. Maybe assume a 1ft length has the reduced section and see what the flexural capacity is using flat plate bending.

That seems reasonable to me?