I-Corps: Bio-inspired ground anchor technology

The broader impact/commercial potential of this I-Corps project is the development of a bio-inspired ground anchor technology. Ground anchors are a structural component of many retaining walls and building foundations that resist forces attempting to pull the structure from the ground by transferring those forces to the surrounding soil. Such forces are called pullout loads.

The conventional ground anchor may be fabricated and installed easily using simple tooling and components, but they are not highly efficient at resisting pullout loads. An economically competitive alternative to conventional ground anchors must be nearly as simple to install and more efficient in its use of materials. The proposed technology uses a bio-inspired root design to meet these criteria.

The geometric design of root systems resists pullout loads more efficiently than the cylindrical external interfaces of conventional ground anchors. The proposed technology seeks to develop higher pullout load capacities than conventional anchors within a shorter bonded length. Shorter anchors use less cement and steel, require less drilling, consume less diesel fuel, and require fewer working hours to install.

This I-Corps project is based on the development of a root-inspired ground anchor system. Prototypes have been studied in the lab as well as in preliminary field trials and they have demonstrated the feasibility of installing, expanding, and loading the bio-inspired system. The ongoing research is focused on scaling-up the technology to full field-scale using both numerical simulations and field tests on instrumented anchors.

The proposed anchor consists of three primary components: a stressing element identical to the steel cables or bars used in conventional ground anchors; an expansive root mechanism, which is initially cylindrical but expands during installation to mimic the geometry of plant roots; and cement grout, which gives the systems stiffness and protects its components from corrosion. Certain plant species have root systems that anchor the organism in the soil much more efficiently than any ground anchors currently used in civil infrastructure; Their capacity to resist pullout loads is very high relative to the mass of the root system.

The expansive root mechanism of the proposed technology seeks to use the geometric principles of these root systems to resist pullout loads more efficiently than the cylindrical external interfaces of a conventional ground anchor.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.