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Anchors Ahoy!

Who wants to see their home or business blown/floated off its foundation like a ship adrift? No one, excepting Captains Nemo and Ahab. So, let’s go over anchors and how they keep structures grounded.

Historically, bent anchors have been the preferred choice, but recently, headed anchors have been aiming to steal the spotlight. There are quite a few reasons why headed anchors are clearly a better option than bent and hook/J/L anchors.

According to ACI 318 Appendix D 5.3.5, AISC 360-10 equation J3-1, and ACI 318 17.1.3, a successfully embedded anchor bolt will form a breakout cone with the concrete.

Pullout strength is the force required to pull the anchor bolt out of its concrete member without substantially damaging the concrete. As can be seen below, anchors tend to pullout of concrete. Whereas headed anchors typically achieve the maximum tension capacity of concrete and form a breakout cone.

         BENT ANCHOR                                               HEADED ANCHOR

Besides choosing the right anchor, it is also important to understand what finishes should be specified. Corrosion is an important factor when selecting materials. Exposures can range from, interior dry service to an exterior ocean-front location. Typically, interior corrosion is slower and less severe while exterior corrosion is faster and more severe because of environmental factors such as moisture, acid rain, and chemicals. Dissimilar metals can also affect corrosion rates, see AISC table 2-7.

Regardless of which anchor you choose to fit your project; you can find all of these supplies at Fastening Specialists Inc.

Author: Sofia Covelli