User guide

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C-11
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.