Applied Loads and Stability of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 215

Table 3.29 Characteristic Values of the Friction Coefficient m K Recommended by EC3
(BS EN 1993-2) [1.27]
Surface Treatment of Steel Components

Steel on Steel Steel on Concrete

Uncoated and free from grease 0.4 0.6

Metal-sprayed
Coated with fully hardened zinc silicate
Other treatments

From tests From tests

take place before clearances are taken up. The total clearance between the
extremes of movements may be up to 2 mm unless otherwise specified or
agreed with the manufacturer.

3.11.5 Design Rules for Fabricated Steel Bearings
The design rules for fabricated steel roller bearing are provided in EC1 (BS
EN 1337-4) [ 3.12 ] . According to the code, only ferrous materials (see
Table 3.30 ) shall be used in the manufacture of rollers and roller plates. Rol-
lers and roller plates shall have a surface hardness less than that specified by
the code. Carbon steel shall be in accordance with the requirements of EN
10025 [ 3.13 ] or EN 10083-1 [ 3.14 ] and EN 10083-2 [ 3.15 ] , with a mini-
mum yield strength of 240 N/mm 2 . Stainless steel shall be in accordance
with EN 10088-2 [ 3.16 ], with a minimum tensile strength of 490 N/
mm 2 for any component. Cast steel shall be in accordance with ISO
3755 [ 3.17 ] . The design of roller bearings is based on the assumption that
load passes through a Hertzian contact area between two surfaces with dis-
similar radii. Design verification with respect to loading and rotation (move-
ment) should be determined in accordance with BS EN 1337-1 [ 3.11 ] . The
design values of the effects (forces, deformations, and movements) from the
actions at the supports of the structure shall be calculated from the relevant

Table 3.30 Ferrous Material Classes According to BS EN 1337-4 [ 3.12 ]

Tensile
Strength
(Minimum)
(N/mm 2 )

Yield
Strength
(Minimum)
(N/mm 2 )

Surface
Hardness
(Maximum)
(HV 10)

Impact/At
Temperature
(Minimum) (J)

Elongation
(Minimum)
(%)

Friction
Coefficient
(Maximum)

Material
Class

27/0 C

A 340 240 150 25 0.05

27/ 20 C 250 B 490 335 21 0.05

27/ 20 C 450 C 600 420 14 0.02

11/ 20 C 480

D 1350 1200 12 0.02