High strength bolts are tensioned to 70% of the tension
strength of A325 or A490 bolts (RCSC 2004). ASCE Petrochem has been
recommended that anchor rods should be tensioned to a maximum of 33.3% of the
tensile strength of the anchor rod (ASCE Petrochem 1997). I feel that it is reasonable (and it
is my practice) to tension anchor rods to 50% of the tensile
I also assume 20% loss,
a minimum concrete age is required, a tensioning sequence is required, use a
calibrated hydraulic bolt tensioner, and retension after 14 days.
By the way, if vortex
shedding is even close, add strakes.
Date: Wed, 11 Apr 2012 11:16:50 -0600
A question has come up regarding
how much pretension force should be applied to anchor bolts. The
situation is a small stack, 24" in diameter requiring twelve 1" anchor bolts,
each loaded to about 12,000 pounds. I plan to use an 8" high seat for
the bolts. Deflection under wind load is the governing criteria.
Does anyone have any thoughts on
Thank you in advance for your
H. Daryl Richardson