CHANCE Helical Anchors

Since the early 1960s, A.B. Chance Helical Anchors have been used in the electric transmission industry as the primary guy anchor solution. Today, CHANCE Helical Anchors are finding increasing popularity in civil construction applications because of the versatility and cost effectiveness of this uplift (tension) restraint solution.

CHANCE Helical Anchors extend bearing plates through soft, loose, or expansive surface soils into stable strata with minimal disturbance. Discover the predictable, cost-effective, quickly installed alternative to traditional uplift restraint methods.

Helical anchors are commonly selected for earth anchoring applications because they are quick to install and can be proof-tested and loaded immediately with no concrete to cure or de-watering of the excavation. Helical anchors are often chosen over traditional anchoring methods such as concrete deadmen or grouted anchors to overcome limited accessibility or the presence of a high water table.

A helical tieback anchor is a segmented deep foundation system with helical bearing plates welded to a central steel shaft. The load is transferred from the shaft to the soil through these bearing plates.

Tieback anchors are installed by rotating the anchors into the ground with rotary drilling equipment. Once the minimum depth is reached, the capacity can be determined by reading the installation torque and correlating it to the holding capacity ratio. This system’s capacity can reach up to 55,000 pounds per anchor.

• High production capabilities

• Minimal vibration or displacement of soil during installation

• Instant load capacity

• Installation Torque continuously monitored

• No spoils removal (ideal for contaminated site conditions)

• Easily installed in areas with limited access

CHANCE Helical Anchor Installation Overview

A helical anchor is used to resist tensile loading. For these tension-only anchors, square shaft helical anchors are the logical choice. The helical anchor is segmented with helical bearing plates welded to a central steel square shaft.

The load is transferred through the shaft to the soil through the bearing plates. Anchors are coupled together with couplings, and the only limits to installation depth for these anchors are soil conditions such as density. Engineers can achieve whatever depth makes sense economically.

Since the plates are helical, they do not auger but rather screw into the soil with minimal disturbance. Helical bearing plates have a standard 3″ pitch and are spaced at far enough distances that they bear load independently of one another; therefore, the load capacity of one is not influenced by adjacent plates.

The success of the Helical screw anchors is based on decades of similar use of CHANCE anchors by electrical utilities. The proven reliability and engineered predictability of the system’s performance give you anchors that are permanent, economical, and hassle free. Engineered for dependability and long-term stability, the CHANCE Helical Wall Anchor System features exclusive anchoring techniques, tools, designs, and sizes that make other foundation methods a thing of the past. It provides a smart, cost-effective solution for bulging, bowing, or cracked walls.

There is no grout used, so installed anchors can be tested immediately, and concrete trucks or grout pumps are not required. They can be installed in almost any weather using conventional drilling equipment. CHANCE Anchors from Intech Anchoring have predictable holding strength in all soils.

The A.B. Chance Helical Retaining Wall Anchor System components include Lead Helix, Extension(s), Anchor Termination, and Wall Plate (or C-channel for blocked foundations).

The installation steps include:

• • The foundation is prepared for anchor installation by drilling 3″ diameter holes at each anchor location from the inside to the outside.

• • After the helical anchor is screwed into the inactive soil, it is then extended through the drilled hole in the wall.

• • From the inside, a wall plate (or a steel 6″ C-channel for blocked foundations) is attached to the anchor and tightly secured.

To learn more about the details and applications of Chance Helical Anchors, contact Intech Anchoring today.