Eurocode 0: basic concepts of structural designs

Eurocode 0 establishes the basic instructions to use the Eurocodes for structural design. Discover the basic structural requirements of buildings

Eurocode 0 introduces the elementary notions related to construction and provides some basic information concerning the structural requirements of buildings.

With the ever increasing need to design safe and functional buildings, it seems quite obvious that you can’t produce the structural analysis for new or existing buildings without respecting the technical concepts introduced in the Eurocodes.

With this in mind, I suggest using a structural engineering analysis software for modelling, analysing, designing and preparing construction documents in compliance with Eurocodes (EC) and the various relating national annexes.

Eurocode 0: basis of structural design

The Eurocodes (EC) are the set of European standards for structural design, which allow the application of a common structural calculation criteria all over Europe and many countries outside of Europe, some of which were previously connected to the abandoned British Construction standards, such as Malaysia, Singapore, Vietnam, Hong Kong and a range of others, closer to the EU, such as Turkey, the Balkan region, Albania, Ukraine.

Generally speaking, Eurocodes 2 for concrete, EC 3 for steel, EC 4 for composites, EC 5 for timber and EC 9 for aluminium structures seem to be the most widely accepted whilst Eurocodes 1, 7 and 8 are the least applicable outside of the EU. We’ll see a little more about how the EC standard is structured further on.

These standards were initially introduced by the Technical Committee CEN/TC 250 “Structural Eurocodes”, which has the overall responsibility for all CEN work on structural design codes.

“Eurocode: Basis of structural design“, informally Eurocode 0; abbreviated EN 1990 or EC 0 forms the basis that sets out the way to use the Eurocode series of European standards (EN) for structural design.

Eurocode 0 is indeed intended to be used in conjunction with EN 1991 to EN 1999 for the structural design of buildings and civil engineering works, including geotechnical aspects, structural fire design, situations involving earthquakes, execution and temporary structures.

More precisely, from EN 1991 to EN 1999, the Eurocodes Standards are:

• EN 1991 Eurocode 1: Actions on structures;
• EN 1992 Eurocode 2: Design of concrete structures;
• EN 1993 Eurocode 3: Design of steel structures;
• EN 1994 Eurocode 4: Design of composite steel and concrete structures;
• EN 1995 Eurocode 5: Design of timber structures;
• EN 1996 Eurocode 6: Design of masonry structures;
• EN 1997 Eurocode 7: Geotechnical design;
• EN 1998 Eurocode 8: Design of structures for earthquake resistance;
• EN 1999 Eurocode 9: Design of aluminium structures.

Eurocodes-CENTC250

Today, Eurocode 0 is also useful for:

• the design of structures where other materials or other actions outside the scope of EN 1991 to EN 1999 are involved;
• the structural assessment of an existing construction, in developing interventions for repairs and alterations or in assessing change of use.

Eurocode 0 may be used as a guidance document for the design of structures outside the scope of the EN Eurocodes EN 1991 to EN 1999, for:

• assessing other mechanical actions and their combinations;
• modelling material and structural behaviours;
• assessing numerical values of the reliability format.

This standard also introduces the definition of some common terms and conventional symbols used in EN 1990 to EN 1999, such as the design working life of a building.

Structural requirements of a building

Eurocode 0 introduces the basic structural requirements of a building.

A structure should be designed and made in such a way that, during its intended life, it will have appropriate degrees of reliability and be economically sustainable.

Every structure should:

• sustain all actions and influences that could occur during execution and use;
• remain fit for the use for which it is intended.

What are the requirements of structural design?

A structure should be designed and executed so that it will not be damaged by events, such as explosion, impact, earthquakes, fires, or the consequences of human error.

Therefore, some basic requirements should be considered during the structural analysis and design because a structure should have an adequate:

• degree of robustness;
• structural resistance;
• serviceability;
• durability.

Basic building requirements

For example, in the case of fire, the structural resistance should be adequate for the required period.

The basic requirements should be fulfilled by:

• the choice of suitable materials;
• the appropriate design and detailing;
• the specification of control procedures for design, production, execution, and use.

Moreover, potential damage should be avoided or limited by:

• avoiding, eliminating or reducing the hazards to which the structure can be subjected;
• selecting a structural form which has low sensitivity to the hazards considered;
• selecting a structural form and design that can continue to exist adequately after the accidental removal of an individual member or a limited part of the structure;
• avoiding as far as possible structural systems that can collapse without warning;
• tying the structural members together.

Reliability management of a building

Eurocodes propose some general aspects related to reliability and quality management: different levels of reliability may be adopted for structural resistance and serviceability.

The reliability required for structures within the scope of EN 1990 could be obtained by means of:

• a structural analysis and design produced in accordance with EN 1990 to EN 1999;
• an appropriate execution;
• the implementation of some quality management measures.

The choice of the levels of reliability for a particular structure, should take into account some relevant factors:

• the possible cause and/or mode of attaining a limit state;
• the possible consequences of failure in terms of risk to life, injury, potential economic losses;
• public aversion to failure;
• the expense and procedures necessary to reduce the risk of failure.

The designer has to determine the levels of reliability for application in a specific structure. These levels may be specified in one or both of the following methods:

• by the classification of the structure as a whole;
• by the classification of its components.

These levels of reliability can be achieved by combinations of different measures:

• preventative and protective measures (e.g. implementation of safety barriers, active and passive protective measures against fire, protection against risks of corrosion such as painting or cathodic protection);
• measures relating to design calculations;
• measures relating to quality management;
• measures aimed to reduce errors in design and execution of the structure.

Design working life of a building

An important value in the structural analysis and design of a building is the design working life.

The design working life is “the assumed period for which a structure or part of it is to be used for its intended purpose with anticipated maintenance but without major repair being necessary“(Eurocode 0 EN 1990).

The designer must specify this value in the structural project.

In Eurocode 0, structures are classified into 5 categories, each including specific kinds of constructions. According to the different types of structures, an indicative working life is expressed in years.

Specifically, the above table shows that:

• category 1 includes temporary structures that should have a design life of at last 10 years;
• category 2 includes replaceable structural parts, such as gantry, girders and bearings with a variable design working life from 10 to 25 years;
• category 3 considers agricultural and similar buildings with a design life from 15 to 30 years;
• category 4 considers buildings and other types of constructions with a minimum life of 50 years;
• category 5 covers monumental buildings, bridges and other strategically important civil engineering structures with a design life with at least 100 years.

Eurocode 0 also specifies that structures or parts of structures that can be dismantled with a view to being re-used should not be considered as temporary.

Durability of a building

Structures should be designed such that deterioration over its design working life does not damage the performance of the structure, in compliance with its environment and the anticipated level of maintenance.

In order to achieve an adequately durable structure, different factors should be taken into account. They are:

• the intended or foreseeable use of the structure;
• the required design criteria;
• the expected environmental conditions;
• the composition, properties and performance of the materials and products;
• the properties of the soil;
• the choice of the structural system;
• the shape of members and the structural detailing;
• the quality of workmanship and the level of control;
• the protective measures;
• the intended maintenance during the design working life.

Environmental conditions should also be identified at the early design stage so that their significance can be assessed in relation to durability and adequate provisions can be made for protection of the materials used in the structure.

The degree of any deterioration may be estimated on the basis of calculations, experimental investigation, experience from earlier constructions, or a combination of these considerations.

That’s mainly why I suggest you use this structural analysis and design software for new and existing buildings with reinforced concrete, steel, masonry and timber elements, that will guide you step by step.

Quality management of a building

In order to provide a structure that corresponds to the requirements and to the assumptions made during the design phase, appropriate quality management measures should be taken in place. These measures consider:

• definition of the reliability requirements;
• organisational measures;
• controls at the stages of design, execution, use and maintenance.

To calculate an accurate structural analysis according to the Eurocodes by respecting the different measures, I recommend using a specific structural engineering analysis software, where, by starting a new project, you can set the ‘Eurocodes’ as your reference standard to be applied for regulatory structural verifications.

EdiLus eurocodes and national annexes

The software’s great flexibility also allows you to set the necessary parameters for the application of the Eurocodes in accordance with the National Annexes published by a specific country so that, after selecting the National Annex to be used, all national parameters will be set automatically in accordance with the rules adopted by the specific country.

EdiLus eurocode: national annexes