Tensile Bending Stresses in Mortar-Grouted Riprap Revetments Due to Wave Loading

Abstract

One of the most common revetment types in Germany is the mortar-grouted riprap revetment (MGRR), which is constructed by placing riprap on a filter or separation layer and subsequent grouting with mortar. Existing technical standards and guidelines for MGRRs do not consider the interaction between dynamic wave loading and structural response. To date, scientifically sound design approaches verified by model tests are missing. Therefore, the aim of this work is to establish a process-based model for the calculation of the acting bending tensile stresses during wave attack for MGRRs to asses crack formation. To this end, MGRRs were modelled as plates on an elastic foundation (PEF). Hydraulic boundary conditions were determined with full-scale hydraulic model tests. Model parameters of the PEF model were established by investigations into the mechanical parameters of the constituents of MGRRs. The results show that tensile bending stresses are particularly dependent on the pressure difference between the top and bottom edge of the top layer, which varies significantly for MGRRs as their porosity and permeability varies significantly depending on the amount of mortar used for grouting. Enveloping functions for maximum relative tensile bending stress σx,max/(ρwgHm0) are given for four configurations of MGRRs that are of great practical relevance.

Modelling of Harbour and Coastal Structures

“…Following a combined physical and numerical modelling approach as well, ref. [13] investigates the interaction between wave loading and structural response for mortar-grouted riprap revetments, adopting the Plate on an Elastic Foundation model for the in-house algorithm developed for their numerical analyses. Focusing on an issue relevant to the stability of most structures built in the marine environment, ref.…”