1. Due to some incident on site some angles and beams were twisted around 20degrees.
Can these members retained on site retained to their original shape without effecting assumed elastic properties, procedure?advise?
I would say "no" to that as a general rule, but it depends on what exactly happened.
If they have been twisted to a new "permanent" geometry, that means that they have been accedentally "cold-formed". Then they will have built-in stresses due the partial plastic deformations.
Things like that can be analyzed to investigate the effect and at least get an idea regarding the residual stresses. But is it worth the effort?
Even if you manage to push them back to the original geometry, you will have a stress distribution that is affected by the yielding in the load history. It can perhaps be managed, but is it worth the effort ?
My opinion is , fixing /straightening could be option if the profile low carbon mild steel and with flame straightenning process rather than cold bending or hammering..
I would remind also , fixing /straightening requires experienced workmanship..
If you write ( straightening steel beam ) and search the forum ,
some of the outcomes;
- thread507-106922
- thread607-377464...
The following video is useful to get flame straightening concept..