Question

1- a) What is the only ASTM nut type for galvanized bolts?

b) Name the four methods of pre-tensioning high strength bolts.

c) What is the nut rotation from the snug-tight condition for each bolt for turn-of –nut pre- tensioning in amount of turn and degrees required, both faces normal to bolt axis:3/4in A325 2.75 in. length,3/4in A490 2.75in length,7/8in A490 4in length and 7/8in A325 8in length.

Answer 1

1(a)

ASTM A153 is the processing parameters and general requirements of hot-dip galvanized bolts.

(b)

(i) Freyssinet System.

(ii)Magnel Blaton system.

(iii)Gifford Udall System.

(iv)Lee McCall System.

(c)

As with every bolt pretensioning method, Turn-Of-Nut may only be performed after all steel plies in a connection have been drawn into firm contact, i.e. snug-tightened.

Failure to do so will result in inadequate bolt pretension and loose connections.

Turn-Of-Nut is performed by rotating the nut or bolt of a fastener assembly a specific turn angle based on the fastener's length, and diameter while restraining the unturned element from rotating.