Mueller Pre-Fab - Manual (Page 31)

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JoInTs noT sUbJecT To TensIon loaDs
Joints not subject to tension loads need only be tightened to the snug tight condition, defined as
the tightness attained by a few impacts of an impact wrench or the full effort of a man using an
ordinary spud wrench .
Joints subject To Tension loads
Two tightening procedures are specified for A325 bolts in joints subject to tension loads, turn-of-
the-nut method and direct tension indicator .
Turn-of-the-nut method – When turn-of-the-nut method is used to provide tension, first bring
enough bolts to a “snug tight” condition to ensure that the parts of the joints are brought into good
contact with each other . Next, place bolts in all remaining bolt holes and bring to “snug tight” .
Then additionally tighten all bolts – progressing from the bolts nearest the web, to the free edges .
During this operation there shall be no rotation of the part not turned by the wrench .
Tightening by use of a direct tension indicator – Tightening by this means is permitted provided
it can be demonstrated, by an accurate direct measurement procedure, that the bolts have been
tightened to specified tension .
Consult latest edition of the AISC Manual of Steel Construction for more complete instructions for
installing high strength bolts .