Anchoring the Anchors
Hold-down bolts and hold-down straps must be securely fixed
in place both laterally and vertically (Figure 3).
| |
| Figure
3. The author uses plywood templates (top left)
or Simpson "Monkey Paws" (top right) to secure
hold-down bolts to foundation form boards. Embedded
strap anchors are tacked into place, while post anchors
(bottom left) are temporarily secured to a scrap of
framing lumber of the correct width. |
If they move sideways during the pour, they’ll miss
the structural member that they are supposed to anchor. If a
bolt moves up, it won’t embed into the concrete enough.
If it moves down, it gets embedded too deep into the concrete
and there won’t be enough exposed thread to make a
connection. (If a bolt happens to sink into the concrete during
the pour, a threaded union and a piece of all-thread the same
diameter as the bolt can be used to lengthen the exposed
shank.)
The inspectors in our area require that all hold-down bolts
be in place before the pour. Using the color highlights on the
plans for reference, I spray paint the matching locations on
the formwork to make the job easier for the inspector. Then we
install plywood templates and jigs to lock the bolts in their
proper locations during the concrete pour. When we require
extreme accuracy, we use the Simpson MKP (monkey paw anchor
bolt holders) to help secure bolts prior to concrete
placement.