BSI BS EN 1991-1-8:2026

1.1 Scope of EN 1991 1 8

(1) EN 1991 1 8 gives principles and rules to determine the values of wave and current actions on structures and civil engineering works in the coastal zone, i.e. works connected to, or in close vicinity to the shore.

NOTE 1 Provisions in EN 1991 1 8 are limited to hydrodynamic actions that can be directly quantified in terms of wave and/or current induced pressures and associated forces and moments on structures or structural parts.

NOTE 2 As opposed to offshore conditions, waves or currents in the coastal zone are generally affected by the presence of the seabed or shore.

NOTE 3 The coastal zone is typically defined as the area between the shoreline and the deep-water limit.

(2) EN 1991 1 8 describes the principles for defining the hydrodynamic conditions to be used for design, including sea water levels.

(3) EN 1991 1 8 addresses specifically actions from currents and waves on the following structure types:

• cylindrical structures;
• subsea pipelines;
• suspended decks;
• vertical face structures;
• permanently moored floating structures.

NOTE 1 Additional guidance can be needed for:

• moored structures in the coastal zone for renewable energy production or related to oil and gas production or processing;
• moored structures spanning areas with variable wave and current states (e.g. floating aquaculture farms or floating bridges).

NOTE 2 For hydraulic pressures caused by quasi-static water levels, and ground water, see EN 1997 (all parts).

(4) Actions addressed in EN 1991 1 8 do not cover:

• hydraulic resonance in sheltered areas or basins (phenomena also known as harbour resonance);
• translation waves, e.g. tsunamis;
• waves and currents induced by maritime operations, i.e. vessel wake, berthing and mooring;
• hydrodynamic actions induced by earthquakes;
• ice-induced pressures and forces;
• coastal structures where flood risk and/or erosion or sediment management is the dominant function.

1.2 Assumptions

(1) The assumptions given in EN 1990 apply to this document.

(2) In addition, it is assumed that actions from waves and currents on coastal structures are determined by personnel appropriately qualified and experienced in the following fields:

• a) physical coastal environment including physics of waves and currents, statistical properties and propagation of such;
• b) marine hydrodynamics, wave and current interaction with structures in general and wave and current actions on structures in the coastal zone including
  • i) fixed structures, and
  • ii) floating structures;
• c) advanced methods including probabilistic methodology and physical model testing.