Hydraulic design recommendations for eco-engineered single-layer armour units
Serim Dogac Sayar (University of Ottawa)
Jorge Gutiérrez Martínez (ECOncrete AQUA SL)
Scott Baker (National Research Council Canada)
Ioan Nistor (University of Ottawa)
Yaeli Rosenberg (ECOncrete AQUA SL)
Bas Hofland (TU Delft - Civil Engineering & Geosciences)
Jeroen van den Bos (Royal Boskalis Westminster N.V)
Fernando Colom Jover (ECOncrete AQUA SL)
Stefano Kerr (University of Ottawa)
Aron Lawniczak (Student TU Delft)
Auke Molenkamp (Student TU Delft)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
This paper presents the first consolidated hydraulic design recommendations for the Coastalock™ armour unit, an eco-engineered single-layer armour system. Based on 306 individual sea-state test runs from four independent physical modelling campaigns conducted at the National Research Council Canada (NRC) and at Delft University of Technology (TU Delft), this study establishes a consolidated empirical basis for design. Hydraulic performance was expressed in terms of the stability number (Ns) and the Hudson coefficient (KD) for both permeable and impermeable cores with 2V:3H and 1V:2H slopes. The best-performing configuration (for a 2V:3H slope) consisted of protruded Coastalock units at 22.5% spacing on a permeable core; the resulting preliminary design values were Ns ≈ 2.8 and KD ≈ 15, which fall within the range reported for established single-layer systems such as Core-Loc™, Xbloc™, Accropode II™, and Cubipod®. Armour unit spacing (defined as the intentional lateral gap between adjacent units expressed relative to the nominal armour diameter) and underlayer sizing were identified as the main effective parameters for hydraulic stability. The best performance for the tested configurations was observed for underlayer-to-armour layer nominal diameter ratios between 0.25 and 0.34, interpreted within the tested spacing, core permeability, and placement conditions. Overtopping analysis, calibrated against EurOtop formulas, produced γf values primarily between 0.65 and 0.70, reflecting the overtopping characteristics of Coastalock. Ecological monitoring is acknowledged as design context, as the unit cavities can function as water-retaining tidal pools and shaded refuges; however, the recommendations presented here are focused on hydraulic stability, overtopping, underlayer response, and toe/rear side response observations. These findings indicate that Coastalock has potential as a dual-purpose single-layer armour unit. The recommendations based on the tested structural configurations and hydraulic conditions provide a research-based framework for preliminary hydraulic design of single-layer eco-engineered Coastalock armour units.
help_outline