Helical anchors, often called screw anchors, are commonly used for underpinning and settlement arrestment; however, they can also be used for tiebacks, uplift anchors and new construction piles. The pile is constructed simply by screwing the anchor into competent load-bearing soil.
The pile capacity is a function of the installation torque achieved during installation. Helical anchors come in various shaft sizes and helix configurations, allowing for lots of options to meet the required specifications.
Advantages of Helical Anchors
The major advantages of helical anchors are speed of installation and the ability to load the pile immediately. Since there’s no need to wait for grout to cure, you can get back to work right away.
Another benefit of helical anchors is that they can be installed with relatively small equipment and in areas with very tight access. Also, there are no spoils left from the installed pile, making the installation process very clean compared to other pile types.
Helical anchors have their disadvantages, too. For starters, they cannot be installed into or through rock. Also, lateral stability or buckling can be a concern in certain soil conditions.