1. General

This website presents design data in tabular formats as assistance to engineers who are designing buildings in accordance with BS EN 1993-1-1: 2005[1], BS EN 1993-1-5: 2006[1] and BS EN 1993-1-8: 2005[1], and their respective National Annexes. Where these Parts do not give all the necessary expressions for the evaluation of data, reference is made to other published sources.

The symbols used are generally the same as those in these standards or the referred product standards. Where a symbol does not appear in the standards, a symbol has been chosen following the designation convention as closely as possible.

1.1Material, section dimensions and tolerances

The structural sections referred to in this design guide are of weldable structural steels conforming to the relevant British Standards given in the table below:

Table – Structural steel products

Product Technical delivery requirements Dimensions Tolerances
Non alloy steels Fine grain steels
Universal beams, Universal columns, and universal bearing piles BS EN 10025-2[2] BS EN 10025-3[2]
BS EN 10025-4[2]
BS EN 10365[3] BS EN 10034[4]
Parallel flange channels BS EN 10365[3] BS EN 10279[6]
Angles BS EN 10056-1[7] BS EN 10056-2[7]
Structural tees cut from universal beams and universal columns BS EN 10365[3]
Hot finished structural hollow sections BS EN 10210-1[8] BS EN 10210-2[8] BS EN 10210-2[8]
Cold formed hollow sections BS EN 10219-1[9] BS EN 10219-2[9] BS EN 10219-2[9]
For full details of the British Standards, see the reference list at the end of the Explanatory Notes.
EN 1993 refers to the product standards by their CEN designation, e.g. EN 10025-2. The CEN standards are published in the UK by BSI with their prefix to the designation, e.g. BS EN 10025-2.

1.2Dimensional units

The dimensions of sections are given in millimetres (mm).

1.3Property units

Generally, the centimetre (cm) is used for the calculated properties but for surface areas and for the warping constant (Iw), the metre (m) and the decimetre (dm) respectively are used.

Note: 1 dm = 0.1 m = 100 mm
  1 dm6 = 1 x 10-6 m6 = 1 x 1012 mm6

1.4Mass and force units

The units used are the kilogram (kg), the Newton (N) and the metre per second squared (m/s2), so that 1 N = 1 kg x 1 m/s2. For convenience, a standard value of the acceleration due to gravity has been accepted as 9.80665 m/s2. Thus, the force exerted by 1 kg under the action of gravity is 9.80665 N and the force exerted by 1 tonne (1000 kg) is 9.80665 kiloNewtons (kN).

1.5Axis convention

The axis system used in BS EN 1993 is:

x along the member
y major axis, or axis perpendicular to web
z minor axis, or axis parallel to web

This system is convenient for structural analysis using computer programs. However, it is different from the axis system previously used in UK standards such as BS 5950.