Eurokod, grund

EN 1991-1-4 gives principles and rules for the determination of natural wind actions for the structural design of building and civil engineering works for each of the loaded areas under consideration. This includes the whole structure or parts of the structure or elements attached to the structure, e.g. components, cladding units and their fixings, safety and noise barriers. This part is applicable to: - buildings and civil engineering works with heights up to 300m; - bridges having no span greater than 200m. This part is intended to predict characteristic wind actions on land-based structures, their components and appendages. This part is also applicable to structures less than 1km offshore from the main coastline. For offshore structures more than 1km from the main coastline, the terrain effects defined in this part do not apply.

1.1 Scope of prEN 1991-1-6 (1) prEN 1991-1-6 provides guidance and general rules on the determination of actions relevant for the design of buildings and civil engineering works, including geotechnical structures, for their execution stage.

NOTE Actions for design during execution include those that only arise from execution activities and act during execution, termed construction actions (for example personnel and hand tools, auxiliary structures, equipment and elements used during execution), and others that are present during the service life of the completed structure (for example self-weight, wind, etc.) but which can act differently and/or have different values during execution.

(2) prEN 1991-1-6 provides guidance and general rules for the determination of actions for the design of auxiliary structures, elements and equipment used during execution in case they are designed to the Eurocodes and not to other European Standards.

NOTE Other European Standards (e.g. EN 12810, EN 12811, EN 12812) provide specific rules for certain types of auxiliary structures, equipment and elements used during execution.

(3) prEN 1991-1-6 gives rules for buildings and bridges during execution to supplement the provisions in EN 1990.

NOTE For combination rules for execution, see EN 1990.

1.2 Assumptions

(1) The general assumptions given in EN 1990 apply.

(2) The application of this document follows the limit state principle and is based on the partial factor method, unless explicitly prescribed differently.

(3) The verification of buildings and civil engineering structures in transient design situations is undertaken in accordance with the Eurocodes, accounting for the interaction with any auxiliary structures, elements and/or equipment.

(4) When using European product standards covering auxiliary structures, equipment and elements used during execution, it is assumed that the design basis, design requirements and, if provided, the safety and operational design limits specified in these product standards are taken into account.

(5) Adequate planning, documentation, communication, control and supervision are provided during execution, involving all relevant parties.

NOTE Execution of a structure can involve interaction between several parties from diverse engineering fields, responsible for the design, fabrication, transportation and execution of different subsystems used during the execution of a structure.

(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 or in close vicinity to the shore.

NOTE 1 As opposed to offshore conditions, waves or currents in the coastal zone are substantially affected by the presence of seabed or shore.

NOTE 2 In typical seabed morphology the affected area lies between the shoreline and the deep-water limit.

(2) EN 1991-1-8 describes the principles for defining the design sea conditions, including design water level variability for structures in the coastal area.

NOTE Wave and current conditions vary for different construction sites. It is very important to assess the wave and current conditions at a given site. Assessment procedures for these conditions and for their uncertainties are included in this document.

(3) In EN 1991-1-8 the following structure types are specifically addressed:

— cylindrical structures;

— suspended decks;

— sub sea pipelines;

— breakwaters:

— mound breakwaters;

— vertical face breakwaters;

— composite breakwaters;

— coastal embankments:

— revetments;

— seawalls;

— permanently moored floating structures.

NOTE Additional guidance can be needed for:

— floating platforms in the coastal zone related to oil and gas production or processing;

— floating platforms in the coastal zone for renewable energy production.

(4) EN 1991-1-8 does not fully cover principles for determining actions from waves and currents on:

 port structures like piers, jetties, quay walls, marine terminals in sheltered marine areas;

 installations for mooring and berthing of ships.

(5) For hydraulic pressures on structural envelopes caused by quasi-static water levels, and for under pressures in the ground, see EN 1997 (all parts).

(6) EN 1991-1-8 does not cover:

 tsunamis;

 hydraulic consequences of an accidental breakdown of water actions from retaining structures;

 waves from passing ships;

 currents induced by jets or ship’s propellers;

 coastal structures where flood risk and/or erosion or sediment management is the dominant function. 

(1) EN 1991-3 defines actions imposed by cranes and other machines including dynamic effects, if relevant, for the structural design of crane or machine supporting structures.

(2) EN 1991-3 provides guidance on crane classification in terms of dynamic factors and fatigue actions.

(3) EN 1991-3 applies to supporting structures of − bridge, gantry and wall cranes travelling on fixed runways; − fixed machines that cause a harmonic dynamic loading on fixed supporting structures.

(4) The principles provided in EN 1991-3 can be applied also to determine actions on supporting structures of cranes other than those referred to in (3).

(5) EN 1991-3 does not provide partial factors for actions.

NOTE For partial factors for actions, see Annex A.5 to EN 1990:2023+prA1:2024.

(6) EN 1991-3 does not provide actions or provisions for the design of cranes and machines.

(1) EN 1991-4 provides guidance for calculating actions for the structural design of silos and tanks.

NOTE 1 Silos are used for the storage of particulate solids: tanks are used for the storage of liquids.

NOTE 2 For limitations on rules for silos given in this document, see 1.3.

NOTE 3 For limitations on rules for tanks given in this document, see 1.4.

(2) EN 1991 4 includes some provisions for actions on silo and tank structures that are not only associated with the stored solids or liquids (e.g. the effects of thermal differentials) but substantially affected by them.

NOTE Liquid loads on tanks are very precisely defined. Many loads on silos are not known with great precision. This standard provides guidance for many practical situations for which very limited certain knowledge is available, and the information is derived from the limited experimental and analytical information available, coupled with conclusions drawn from failure investigations. The information is not based on a sound statistical treatment of experimental data.

(3) EN 1991 4 is intended for use with concrete, steel, aluminium, timber and FRP storage structures.

NOTE FRP is the standard acronym for fibre reinforced polymer materials.

(4) EN 1991 4 may be used for the structural assessment of existing construction, in developing the design of repairs and alterations or for assessing changes of use.

NOTE Where the structural appraisal of an existing structure is being considered, reference can be made to the National Annex and to the client concerning the relevance of the current standard.

Modifications to 1.1, Scope of prEN 1990-1

In the title of the Clause, replace EN 1990 with prEN 1990-1.

Add a new paragraph (2), then have the following subclauses automatically renumbered:

“(2) This document is also applicable for existing structures, with the additional provisions given in prEN 1990-2.”

Replace the new paragraph (3) and (4) with:

“(3) This document is intended to be used in conjunction with the other Eurocodes for buildings and civil engineering works, including temporary structures.

(4) This document describes the basis for structural and geotechnical verification according to the limit state principle.”

Delete the old paragraph (5):

“(5) This document is also applicable for:

— structural assessment of existing structures;

— developing the design of repairs, improvements and alterations;

— assessing changes of use.

NOTE Additional or amended provisions can be necessary.”

Replace the paragraph (6) with:

“(6) This document is also applicable for structures where materials or actions outside the scope of EN 1991 (all parts) to EN 1999 (all parts) are involved.

NOTE In this case, additional or amended provisions can be necessary.” 

(1) This document provides provisions for the assessment of existing structures, including geotechnical structures, and the general principles for interventions, to be used in conjunction with prEN 1990-1. NOTE This document is based on the general requirements and principles of structural reliability provided in prEN 1990-1.

(2) Unless otherwise specified, prEN 1990-1 applies.

(3) This document covers general principles regarding actions for assessment, complementing EN 1991 (all parts).

NOTE Provisions for seismic actions due to earthquake are provided in EN 1998-3.

(4) This document does not cover the design of new structural parts that will be integrated into an existing structure.

NOTE For the design of new structural parts, see prEN 1990-1.

(5) This document does not provide:

— specific rules for initiation of assessment;

— specific rules on how to undertake interventions that may be carried out as a result of an assessment;

— material-specific technical provisions for existing structures;

— provisions for seismic assessment and retrofitting of existing structures.

NOTE For provisions for seismic assessment and retrofitting of existing structures, see EN 1998-3.