Reuse of TC bolts

[Rickaccused]

So I have a project that specified A1852 TC bolts. However, the bolts themselves are not being used in a tension controlled capacity. The contractor needs to remove the bolts so finger shims can be installed between the faying surfaces. I do not require that they reinstall the bolts to tension controlled specifications. Is reuse of the bolts applicable? I believe the spirit of the RSCS indicates that the TC bolts cannot be reused for tension controlled installation, but I am not sure.

Anyone run into this before?

EDIT: I understand the loosening and tightening bolts will be difficult with the domed head on one side.

 

[Agent666]

I believe if bolts have been previously tensioned then they should not be reused (my own local code states this, and I believe AISC recommends the same). This is because tensioning basically can yield the bolts to the proof stress and results in permanent deformation/stretch of the threads.

If you can get them undone using a normal spanner then they have clearly been only done to snug tight, but I think those are twist off bolts right? So to install them they have been been tensioned. So reuse would be a no go.

Even if snug tightened, one erectors snug tight condition vs anothers can be more than simply pulling the plies together, may be tightened partially into the 'tensioned' range (beyond snug tight) depending on how much they attacked it with the rattle gun. So reuse should be carefully considered.

You should be able to inspect the bolts and see if the threads have stretched, often you'll see any coatings starting to flake off due to the permanent stretch. But if they are the twist off type, then they only twist off at the torque required to achieve minimum proof loading assuming proper lubrication, etc.

 

[Ron]

Why use TC bolts in a non-TC application. They are about 3 times the cost of a typical A325 bolt and nut.

 

[ajh1]

If the stem has been twisted off, I would say that you can't reuse them.
If they've simply been put into a snug-tight only position, then you should be able to reuse them. The way to check is if you can thread the nut fully to the end of the threads by hand, then the bolt has not stretched due to yielding and you should be able to reuse them, particularly if your final intent is simply snug-tight or close thereto.

 

[racookpe1978]

If you do attempt to "re-use" the one-time-use bolts, you MUST check EVERY bolt removed.
(You can't check the threads on 4 and approve 150 for use again.) As the guys above indicate, the tension and distortion on each bolt is different every time.

 

[canwesteng]

@ron - some contractors like TC because you only need access from one side for bolt up.