Helical anchors, helical piles used in tension, can be a useful alternative to grouted tendons or other anchoring systems under certain conditions. This article will explore situations where helical anchors are the preferred choice and reference project examples to illustrate the specific issues or product advantages that drove the decision to go with helicals.
Helical Anchors versus Grouted Tendons
Helicals can be a good alternative to grouted tendons based on site specific conditions. Given the right soil conditions, helical anchors will not go as deep as grouted tendons, thereby eliminating right-of-way issues and, together with the elimination of grout, are less costly. Helicals can be load tested immediately, eliminating the wait for the concrete to cure and the expense of remobilization for the testing.
Route 42 Belmawr Road Tiebacks – Danbro Distributors
I-295 Tie Back – Phase 1 – Danbro Distributors
Temporary Tiebacks
Helicals can be easily uninstalled, if necessary, but more typically are left in place for most temporary tiebacks. The ease of installation and mitigation of mobilization and/or access issues are the appeal as with these two highway projects.
SR 141 – I 676 677 Tiebacks – Danbro Distributors
Garden State Parkway Expansion at Mullica River – Danbro Distributors
Slope Stabilization/Soil Nails
Even when shotcrete is a necessary component, as with soil nailing projects, helicals are a solid choice. Both of these jobs involved access roads: one with an active business and the other involving private property concerns.
Pepsi Production Plant – Danbro Distributors
Catskill Aqueduct Repair & Rehabilitation – Danbro Distributors
Sheeting and Shoring
Both of these projects were already utilizing helicals in compression. The Lancaster underpinning project also required sheeting and shoring as part of the fix. Kay Drive was an environmental remediation project, but the contamination delineation footprint went so deep that helical anchors in tension were needed to prevent the deep excavation from collapsing.
Lancaster Shoring – Danbro Distributors
1252 Kay Drive East Cherry Hill NJ – Danbro Distributors
Bulkheads
At Liberty Lake, the tiebacks for a replacement bulkhead served a dual purpose: they facilitated the creation of a lakeside walkway, while the minimally invasive helical fix spared damage to the park. Lighthouse Point’s replacement bulkhead was installed from a barge because there was no access from the land.
Liberty Lake – Danbro Distributors
Lighthouse Point Condos – Danbro Distributors
Tie-downs
Helicals are equally effective for tie-downs. A well-known example is for the tent/bandstand for the musical extravaganza “A Capital 4th “on the lawn of the US Capital each year.
Capital Tent Tie-Down – Danbro Distributors
A high-water table and potential uplift from storm surge are why helicals were used for tiedowns on this residential pool.
Utz Family Pool – Danbro Distributors
In Conclusion
For a variety of reasons, helical anchors offer welcome alternatives to more traditional tiebacks. Join Danbro, IDEAL, and a chorus of other exhibitors in singing the praises of helical anchors for tiebacks on May 7th and 8 th at the Helical Piles – Tiebacks – Anchors Tradeshow in Durham, CT!
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