cross flange welding of existing steel beams

[cmbyrd77]

When is it okay and when should it be avoided to cross flange weld existing steel beams?

 

[jimstructures]

Your question is ambiguous. Please provide clear explanation of your problem and sketch out the layout of what you are attempting to do.
Jim

 

[cmbyrd77]

I have an existing steel industrial structure (built in the 50's) and they are planning on adding a "doghouse" (penthouse, if you will) above the existing structure. I will have to pin the bases of the proposed columns to the top flanges of the existing steel. I am trying to determine if i want to have them field punch holes in the flanges or just weld a clip angle (or something similar) to the flange.