Manta Ray Earth Anchor Systems and Sting Ray Earth Anchor Systems

By: Ancorloc  06-Dec-2011
Keywords: Anchors


Unlike other mechanical anchors, (screw anchors, injection rods) the anchor only disturbs a small amount of soil as it is driven to depth, this is very important, because the soil the anchor is installed through is the soil the anchor is reacting against. This in return gives the anchor the unfair advantage. It is reacting against undisturbed soil.

Manta Ray & Sting Ray Anchors

Manta & Sting Ray Anchor Parts

Manta Ray and Stingray anchors offer many significant advantages:

  • Fast, easy installation
  • Immediate proof test results
  • Inexpensive installation equipment
  • Up to 120 year life.
  • Environmentally friendly
  • No excavation required
  • Superior Holding Capacity
  • Anchors for a wide range of soils & applications

Common applications:


Certified installers:

There are certified Ancor Loc installers covering the South Pacific. Ancor Loc’s installers have a range of installation rigs from Light weight portable rigs to large excavator mounted rigs. Installation of MANTA RAY and STING RAY anchors can be Achieved in almost any situation, cliff faces, low head room and even under water. No job is to big or to small. Call your nearest Ancor Loc dealer for supply and installation pricing, and recommendations for your project.

Excavator rock breakers or compactors:

Boom mounted demolition breakers or compactions are very effective for driving MANTA RAY and STING RAY. Breaker tools and vibro sockets are available from Ancor Loc. Top Hammer or down-the-hole hammer rock drills are very effective for installation of Manta Ray and Stingray anchors. For hard soil or weak rock installations, the drill can be used to drill a pilot hole as well as driving the anchor. Ancor Loc can provide striker bar adapters for these types of drills. Rock drilling steel can also be modified to drive Manta Rays and Stingrays.

Manual Installation:

In some applications, MANTA RAY anchors are driven into the soil with a 40kg. pavement breaker and coupled drive steel. Pneumatic or hydraulic breakers are acceptable, but a 40kg. weight class breaker is necessary. Manual installation of Stingray anchors is not recommended.


MANTA RAY and STING RAY anchors are made of hot dip galvanized ductile iron. Structurally compatible anchor rods and end terminations for guy line or retaining structures are available for all anchor models. A 316 Stainless Steel range of Manta Ray and Sting Ray anchor is available, this range provides life span up to 120 years.


Long Term

Corrosion resistance for up to and in excess of 120 years using Grade 316 passive stainless steel.

Medium Term

Up to and in excess of 50 years using cast iron galvanized anchor heads fitted with galvanized high tensile steel tendons or bars.

Short Term

i.e. temporary works, using cast iron galvanised anchors with either high tensile steel tendons/ bars or galvanised tendons or bars.

NB: All of the above are subject to prevailing ground conditions and the presence of any aggressive properties such as acids or stray electrical currents. Insulators or insulating membranes should always be used to separate dissimilar metals.

Manta Ray and Sting ray anchors are tensile anchors designed to work well in soils with SPT blow counts (N) from 3 to 50. The smaller anchor models are used in harder soils or where lowers loads are required. Larger anchors are used in softer soils. In harder soils, the installed capacity is limited by the ultimate strength of the anchor. In softer soils, it is limited by the soil strength. Soils with blow counts of 35 to 50 and higher, often require the installer to drill a pilot hole prior to installation in order to achieve an efficient installation time. Although they are not intended for installation in rock, some models can be successfully installed into rock formations with low Rock Quality Designation. Typically, a pilot hole is required for these installations, but sometimes anchors can be simply driven into weathered, layered, decomposing rock. Manta Ray and Stingray anchors are designed to react tensile loads along the axis of the anchor rod. They are not designed to react compressive, lateral, or shear loads, however, they can be made to do so by the addition of grout, which will increase the holding capacity, sometimes very significantly. The increase is dependent upon the grout length and soil type.

For retaining structures, Manta Ray anchors should be installed a minimum of 2 metres behind the failure place after proof testing. Stingray anchors should be installed a minimum of 3 metres behind the failure plane after proof testing. A minimum overburden of 1.5 metres must be maintained for Manta Ray anchors and 2 metres for Stingray anchors. Manta Ray and Stingray anchors can be proof tested up to 90% of yield strength. Working loads are typically between 50% and 90% of the proof test value.

Manta and Sting Ray ultimate holding charts


Limited technical services are available to help select anchors and anchoring methods, installation training, and support. Soil boring logs with soil classification and SPT blow counts are required to predict anchor performance. Please contact Ancor Loc with any questions.

Keywords: Anchors

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