Bent Anchor Bolts With Column & Framing Installed

[Eng_Struct]

Hi Group,

For one of our project, contractor had installed the column and framing on levelling plate and nut with column bases ungrouted. Before the GC had a chance to go and grout all column bases, the steel contractor used cables for temporary supports that were tied to column base at a few spots. As part of tensioning the cables, they have bent the anchor bolts.

With all the column and framing already installed, I am not sure how to fix this situation. The fact that column bases have shifted due to bolt bending, my concern is that the columns and framing now may be out of alignment (out of plumb columns, squeezed beam etc) introducing secondary forces in the members.

My question to the talented people here is:

1. Is there really a concern due to misalignment? The bolts have shifted maybe 1/2” to 3/4” max. The columns are perimeter column and 30ft high. I will have the contractor to survey but just wanted to see if I am overthinking. If not, what will be the solution to fix misalignment.

2. I have only have two anchor bolts. Both of them are bent and I don't think i can rely on them to transfer shear. I will need to think of replacing them with column in place. Perhaps extending the pier up around the column with rebar to encapsulate the baseplate to transfer the load directly into the pier.

Thanks!

 

[ANE91]

Doesn’t OSHA require 4 anchor bolts minimum per column?

Anyway, your post reminded me of this video @ 26:07.

1. Guy up the frame until it aligns. Presumably, your design accounted for initial imperfections and resultant secondary stresses.

2. Nothing conceptually wrong with encasing with concrete, but be aware that baseplates have been known to break out of concrete like a giant headed stud. Alternatively, consider possibly welding to the baseplate angles that are bolted to the foundation, as a substitute load path for the deformed anchors.