Steel Designers Manual - TheBestFriend.org

This material is copyright - all rights reserved. Reproduced under licence from The Steel Construction Institute on 12/2/2007
To buy a hardcopy version of this document call 01344 872775 or go to http://shop.steelbiz.org/
Steel Designers' Manual - 6th Edition (2003)
• traction and braking
• derailed vehicles (for overturning consider 80 kN/m over 20 m lengths acting on
the edge of the structure).
Fatigue is important for the design of railway bridges because a higher proportion
of regular traffic attains the maximum loading compared with highway bridges,
and the vehicles are constrained to run in the same lateral paths.
4.6 Other actions
Actions other than traffic loading which may need to be considered in one or more
combinations are shown in Table 4.7. The term ‘action’ is used in Eurocodes to
describe all loads or load effects.
4.7 Steel grades
Steel grades 145
Steels to BS EN 10025 of grade S355 are usual for bridges as they offer a better
cost-to-strength ratio than grade S275.All parts subject to tensile stress are required
Table 4.7 Summary of actions other than those due to traffic loading
Action Comments
Dead loadsa Weight of the structure
Superimposed dead loadsa Finishes and surfacings
Services
Wind Transverse, longitudinal and vertical
Consider in presence of live load or otherwise
Temperature Restraint and movement (e.g. flexure of columns)
Frictional restraint of bearings
Effect of temperature difference
Differential settlement Foundation movements
Earth pressure Vertical and horizontal pressures from retained material
Erection effectsa Strength during construction, e.g. stability of steelwork before
composite floor slab cast
Snow load May be relevant to moving bridges
Seismic As may be specified by the national authority
Water flow Flow against bridge supports
a These actions must be considered during initial design. For most bridge decks actions other than those
from vertical traffic loading, dead and superimposed dead loads are unlikely to have a fundamental
effect.