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Pre-tensioning bolts in hardened epoxy?

Pre-tensioning bolts in hardened epoxy?

Pre-tensioning bolts in hardened epoxy?

(OP)
Hi there,

If bolts are installed as snug tight before the epoxy is placed around the bolts, is it still possible to pre-tension the bolts (using turn of the nut method) after the epoxy is placed and has hardened (see sketch)? Or would the hardened epoxy completely prevent the bolts from turning a 1/2 turn?

RE: Pre-tensioning bolts in hardened epoxy?

What is the purpose of this connection? You can definitely still torque the nut on the bolt after the bolt has been installed and the gap epoxied. I'm assuming you want the epoxy to provide some bearing so that the flange doesn't distort when you torque the bolt? One thing to consider is that depending on the epoxy properties, you run the possibility of cracking/delaminating the epoxy if you torque the bolt too much.

RE: Pre-tensioning bolts in hardened epoxy?

Use tapered washers and/or shims to fill the gap

RE: Pre-tensioning bolts in hardened epoxy?

+1 on tapered washers

RE: Pre-tensioning bolts in hardened epoxy?

(OP)
@damorim That is correct the designer wanted to create a sturdy bearing surface to prevent flange distortion etc. The purpose of the epoxy was also to fill in corrosion pits etc on the steel. Ok well that is good news, at least the bolts can still be pre-tensioned after the epoxy has hardened. I wasn't sure if the the bolts would've needed to be put in a plastic sleeve or something. The bolts are to be pre-tensioned with a 1/2 turn from snug tight.

@MotorCity Thanks for the advice, shims are used along with the epoxy.

RE: Pre-tensioning bolts in hardened epoxy?

We have been using injectable and sheet Dynamold (epoxy) for applications like this for years.

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