Projetando o Eurocode

Designing to Eurocode 2

This chapter is intended to assist engineers with the design of columns and

walls to Eurocode 21. It sets out a design procedure to follow and gives useful

commentary on the provisions within the Eurocode. The layout and content

of Eurocode 2 may appear unusual to designers familiar with BS 81102.

Eurocode 2 does not contain the derived formulae; this is because it has been

European practice to give principles and general application rules in the codes

and for detailed application rules to be presented in other sources such as

textbooks or guidance documents.

Chapter 1, originally published as Introduction to Eurocodes 3, highlighted the

key differences between Eurocode 2 and BS 8110, including terminology.

It should also be noted that values from the UK National Annex (NA) have

been used throughout this publication, including values that are embedded in

derived formulae. (Derivations can be found at www.eurocode2.info.) A full list

of symbols related to column design is given at the end of this chapter.

Design procedure

A procedure for carrying out the detailed design of braced columns (i.e.

columns that do not contribute to resistance of horizontal actions) is shown

in Table 1. This assumes that the column dimensions have previously been

determined during conceptual design or by using quick design methods, for

example those presented in Economic concrete frame elements4. Column sizes

should not be significantly different from those obtained using BS 8110. Steps

1 to 4 of Table 1 are covered by earlier chapters and the next step is therefore

to consider fire resistance.

Fire resistance

Eurocode 2, Part 1–2: Structural fire design5, gives a choice of advanced, simplified

or tabular methods for determining fire resistance of columns. Using tables is the

fastest method for determining the minimum dimensions and cover for columns.

There are, however, some restrictions and if these apply further guidance can

be obtained from specialist literature.6 The simplified method may give more

economic columns, especially for small columns and/or high fire resistance periods.

Rather than giving a minimum cover, the tabular method is based on nominal

axis distance, a (see Figure 1). This is the distance from the centre of the main