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Anchoring the Anchors

Hold-down bolts and hold-down straps must be securely fixed in place both laterally and vertically (Figure 3).

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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.