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Armourstone
Armourstone is a generic term for broken stone with stone masses between (very coarse Construction aggregate, aggregate) that is suitable for use in hydraulic engineering. Dimensions and characteristics for armourstone are laid down in European Standard EN13383. In the United States, there are a number of different standards and publications setting out different methodologies for classifying armourstone, ranging from weight-based classifications to gradation curves and size-based classifications. Stone Classes European Practice to EN13383 Armourstone is available in standardised stone classes, defined by both a lower and upper value of the stone mass within these classes. For instance, Class 60-300 signifies that up to 10% of the stones weigh less than and up to 30% weigh more than . The standard also mentions values which shouldn't be exceeded by 5% or 3%. For particular applications like a top layer for a breakwater (structure), breakwater or bank protection, the me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Van Der Meer Formula
The Van der Meer formula is a formula for calculating the required stone weight for armourstone under the influence of (wind) waves. This is necessary for the design of breakwaters and shoreline protection. Around 1985 it was found that the Hudson formula in use at that time had considerable limitations (only valid for permeable breakwaters and steep (storm) waves). That is why the Dutch government agency Rijkswaterstaat commissioned Deltares to start research for a more complete formula. This research, conducted by Jentsje van der Meer, resulted in the Van der Meer formula in 1988, as described in his dissertation. This formula reads :\frac= \begin c_ P^ \left (\frac \right)^ \xi_m^ & \mbox \xi_m < \xi \quad lunging\\ c_ P^ \left (\frac \right)^ \xi_m^ \sqrt & \mbox \xi_m \ge \xi \quad urging ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
