THE CORE-LOC: OPTIMIZED CONCRETE ARMOR

This paper outlines the development and initial testing of a new optimized armor shape, called CORE-LOC, that balances and optimizes engineering performance features such as hydraulic stability, strength, and layer porosity. The new shape has significantly reduced design stresses over many existing shapes, yet has superior interlocking and therefore greater stability. The unit has internal maximum tensile stress levels of approximately half that of dolosse and, therefore, should not need reinforcement. For over 1000 flume tests, the core-loc has demonstrated two-dimensional no-damage stability numbers over 7 and Hudson stability coefficients over 250. In nearly all tests, the core-loc layer could not be damaged up to the wave height-period capacities of the flumes. A site-specific three-dimensional stability test of the proposed Noyo, California, offshore breakwater showed a stable no-damage stability number of 2.7 for Hs or a Hudson stability coefficient of 13 when the core-loc armor layer was exposed to repeated attack of a very severe design-level storm. The unit has been designed to be used alone or as a repair unit for dolosse. Core-loc-repaired dolos model slopes showed improved stability over the original dolos slopes. Finally, through reduced volumes, the core-loc layer is substantially more economical than all other commonly-used randomly-placed armor.