Select anchorage design using or not using anchor reinforcement.
Unlike anchor bolt in concrete pedestal, it's not a common seen practice
to use anchor reinforcement in vertical vessel anchorage design as it's
difficult to set the floating hairpins in place when pouring the concrete.
User can try not using anchor reinforcement first, and go for using anchor
reinforcement only when the first option doesn't work.
In high seismic design zone where the anchorage design requires higher
ductility, the using anchor reinforcement option may be an option to get
the design passed.
Using Anchor Reinforcement in Vertical Vessel Anchor Bolt Design
Using Anchor Reinforcement - anchor reinforcement strength is used to
replace concrete tension / shear breakout strength as per CSA A23.3-14
Annex D clause D.6.2.9 and D.7.2.9
Not Using Anchor Reinforcement - concretet strength is used to resist
concrete tension / shear breakout strength.
When Using Anchor Reinforcement option is chosen, it normally
significantly increases the anchor bolt capacity, but the code has some
specific requirements for rebar arrangement in order to be considered
being effective for resisting anchor tension and shear.
To take advantage of obtaining higher anchor bolt capacity by using
anchor reinforcement, the trade off is that the engineer has to design
and arrange the rebar around anchor bolt following details in
CSA A23.3-14 Figure D.10 and Figure D.17B.
In the cases such as anchor bolts locating on a concrete pedestal where
the 4-side edge distances are very limited, or the anchor bolt locating on
a high seismic design zone, it would be very difficult to get the anchor
bolt design passed without using anchor reinforcement. In these cases,
uisng anchor reinforcement option normally would be the only choice for
anchor bolt design.
CSA A23.3-14 Figure D.10
To be considered being effective for resisting anchor tension, vertical
reinforcing bars shall be located within 0.5hef from the outmost
anchor's centerline.
CSA A23.3-14 Figure D.17B
To be considered being effective for resisting anchor shear, hor. reinft
shall be located within min( 0.5c1, 0.3c2 ) from the outmost anchor's
centerline
