Home > Media > Fact Sheets > Fact Sheet Article View

Bookmark and Share Email Print

 Single-Layer Sustainable System for Breakwater Protection

 An ongoing research effort is dramatically improving coastal armoring for marine infrastructure, enhancing performance and durability.

Reliable and Cost-Effective Coastal Structure Protection

The ERDC Coastal and Hydraulics Laboratory (CHL) developed and patented CORE-LOC® Concrete Armoring in 1996 to provide reliable navigation and shore protection structures in high wave-energy environments. As a cost-effective system for breakwater protection, CORE-LOC® dissipates the maximum amount of wave energy with the least amount of concrete. This helps protect long-term investments in the performance and durability of marine infrastructure.

Superior Stability and Structural Integrity

Building CORE-LOC® in a random matrix design achieves superior hydraulic stability due to the extraordinary interlocking of its symmetrically-tapered octagonal members. CORE-LOC® provides an optimal blend of structural integrity and hydraulic stability for many open ocean applications.

Designed to withstand the harshest of wave climates, CORE-LOC® is one of the most popular concrete armoring units for both new construction and repair of existing concrete-armored slopes. Benefits include:

  • Minimizes total construction expenses and risks
  • Shortens constructions schedule
  • Requires little to no maintenance for the life of the project

Efficient Wave Energy Dissipation

CORE-LOC® has extraordinary efficiency as a system for breakwater protection:

  • Dissipates the maximum amount of wave energy with the least amount of concrete
  • Reduces costs by as much as 50 percent over many other popular concrete armoring units
  • Minimizes on-slope concrete volume with the lowest packing densities in the industry

Success Stories

CORE-LOC® armoring systems have been used on over 65 prototype structures. The first project was built in 1996 in Port St. Francis, South Africa with 800 15-ton units. This site has endured a number of design level storms with excellent performance.

U.S. Air Force Base, Lajes, Azores, Portugal

CHL conducted two-dimensional and three-dimensional physical model studies of repair scenarios for the breakwater at Lajes Air Force Base. From the research, CHL developed a new CORE-LOC® structure type that combines low maintenance and superior stability with an easy-to-construct underwater semi-mobile rock mound. The physical model study resulted in more than $10 million of direct savings and a considerable reduction in risk.

Manasquan, New Jersey, USA

At an inlet on the Atlantic Ocean at Manasquan, New Jersey, USA, 16-ton steel-reinforced dolosse were in need of repair. To make the project more challenging, all construction and repair work had to be done from floating platforms and equipment stations. CHL researchers studied the crumbling units in the dolosse and recommended replacing them with CORE-LOC® units sized to fit. In spite of challenging logistics, engineers placed all CORE-LOC® units in two days.

Chicago, Illinois, USA

The Chicago River Turning Basin project began as a massive construction effort to control the most serious area of uncontrolled leakage at the mouth of the Chicago River. For the first time ever, CORE-LOC® precast concrete units were used as a unique baffling system. Use of CORE-LOC® reduced by 50% the number of openings and sluice gates necessary to convey the design discharge. CORE-LOC® also ensured hydraulically unrestricted flow conditions in both directions through the sluice gate structure and provided efficient flow energy dissipation to maintain safe navigation and prevent river bed scour.


Model and Full-Scale Testing

  • CHL has conducted extensive testing of the hydraulic characteristics and structural capacity of CORE-LOC® on several types of structures over a wide range of wave heights, wave periods, and water depths.
  • Tests have spanned model units weighing as little as 70 grams to prototype test units as large as 9.2 tons.
  • Many hundreds of additional generalized and site-specific tests of CORE-LOC® technology have been conducted at premier laboratories around the world.
  • CHL estimates the minimum Hudson Stability Coefficient for CORE-LOC® at KD=13 for breaking heads and KD=16 for breakwater trunks.

Practical Formwork for Fast Placement

  • Two symmetrical steel shells
  • No base plates required
  • Quick bolting system for assembly and stripping of the two shells
  • Wheels reduce the use of handling equipment

Licensing and Distribution

CORE-LOC® holds patents and trademarks in more than 45 countries. Several engineering and construction firms worldwide license and distribute this innovative and cost-effective breakwater armoring solution.

For more information about CORE-LOC®, including a list of worldwide prototype projects, visit CHL online.

ERDC Points of Contact

Questions about CORE-LOC®?
Contact: Stephen R. Collinsworth, Program Manager
Email: Stephen.R.Collinsworth@usace.army.mil
Phone: (251) 690-2042

Contact: Jeffrey A. Melby, Technical Lead
Email: Jeffrey.A.Melby@usace.army.mil
Phone: (601) 634-2062

breakwater protection concrete concrete armoring hydraulic stability marine infrastructure navigation shore protection slopes structural integrity wave climates wave energy