High Strength Bolting - Pre-Installation Verification Requirements
High Strength Bolting - Pre-Installation Verification Requirements
(OP)
I am managing construction on a project in California with a pre-engineered metal building. The shop drawings show pretensioned joints with ASTM A325 Bolts. The contractor is planning to use the turn-of-the-nut method to tension the bolts and is arguing that pre-installation verification is not required.
I have pointed out the specific language in the "Specification for Structural Joints Using ASTM A325 or A490 Bolts" requiring pre-installation verification (which is also included on the submitted shop drawings). However, recently, the contractor provided me with a letter from the engineer of record (licensed Civil, but not a licensed Structural, Engineer) for the pre-engineered metal building waiving the requirement for the pre-installation verification. Is this allowable?
Thanks in advance for your comments.
I have pointed out the specific language in the "Specification for Structural Joints Using ASTM A325 or A490 Bolts" requiring pre-installation verification (which is also included on the submitted shop drawings). However, recently, the contractor provided me with a letter from the engineer of record (licensed Civil, but not a licensed Structural, Engineer) for the pre-engineered metal building waiving the requirement for the pre-installation verification. Is this allowable?
Thanks in advance for your comments.






RE: High Strength Bolting - Pre-Installation Verification Requirements
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: High Strength Bolting - Pre-Installation Verification Requirements
However, the EOR can wave or supplement the pre-inspection requirement. This is a liability accepted by the EOR. I am not sure how the EOR for a California project is not an SE, but this may be related to the size of the project.
www.FerrellEngineering.com
Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.
RE: High Strength Bolting - Pre-Installation Verification Requirements
on a seperate note, i have worked on a number of projects with pretensioned bolts and always make sure the preinstall verification testing is done... whether they're installing 5 bolts or 500. given how strong the RCSC langauge is, I would never think of waiving this requirement.
on another note, turn of the nut is what I've typically seen and I would agree that if, they follow the nut rotation requirements of RCSC, it seems unlikely that they would not make the required pretension. personally, I have yet to see a bolt that didn't develop the specified min. pretension when providing the required nut rotation in RCSC.
RE: High Strength Bolting - Pre-Installation Verification Requirements
"personally, I have yet to see a bolt that didn't develop the specified min. pretension when providing the required nut rotation in RCSC."
Do you have some means of testing the installed tension? The Turn of the Nut method can be misleading if the bolts have not been properly snugged beforehand. If not snugged, a bolt with full tension may lose some when the adjacent bolts are pulled up
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: High Strength Bolting - Pre-Installation Verification Requirements
your concern though, is applicable to every type of bolt tensioning method, not just turn of the nut, and the preinstallation testing does not capture this affect since it only tests a single bolt, not a series of bolts in a joint.
regarding the different levels of "snug tight" i agree with you. snug tight to one iron worker is different than snug tight to another iron worker. this is why preinstall testing is important. it allows the ironworker to understand how tight the joint needs to be in ordrer to be considered snug tight. if they dont snug up the joint enough, they will see that turning the nut 1/2 turn, or so, won't develop the required pretension.
that being said, snug seems to be a more or less universal term and I have found that even though the amount of snug can very from person-to-person, the amount of pretension you add by turning the nut 1/2 turn or so past snug more than compensates for the variation in snug.
But, that doesn't mean I will waive the preinstall testing reqs, even if that are using turn of nut!
RE: High Strength Bolting - Pre-Installation Verification Requirements
Correctly marking the bolts is also necessary to properly inspect the installation.
www.FerrellEngineering.com
Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.
RE: High Strength Bolting - Pre-Installation Verification Requirements
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: High Strength Bolting - Pre-Installation Verification Requirements
RE: High Strength Bolting - Pre-Installation Verification Requirements
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: High Strength Bolting - Pre-Installation Verification Requirements
The current RCSC provides a little better description of snug-tight in the current edition. RCSC '09 8.1 all bolts in the joint have been tightened sufficiently to prevent removal of the nuts without the use of a wrench"
www.FerrellEngineering.com
Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.
RE: High Strength Bolting - Pre-Installation Verification Requirements
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: High Strength Bolting - Pre-Installation Verification Requirements
This certainly seems much less restrictive than the old "full effort" method.
RE: High Strength Bolting - Pre-Installation Verification Requirements
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: High Strength Bolting - Pre-Installation Verification Requirements
However, the EOR has no idea where the contractor procured his bolts from (and cannot judge whether they are counterfeit) so I really do not understand why he would take on this liability. In any case, I am much more interested in preventing a potential failure than I am knowing who is liable for the failure if it occurs. So I have asked for details on the bolts that are going to be used. Wish me luck...
As an aside, the Owner's engineer told me that an actual structural license is only required in CA under a few cases (design of schools, hospitals, etc.). A civil license (with a structural background) is sufficient in most other cases.