This Part of this British Standard recommends methods for the fatigue assessment of parts of bridges which are subject to repeated fluctuations of stress.
Standard load spectra are given for both highway and railway bridges.
The following alternative methods of fatigue assessment are described for both highway and railway bridges :
(a) simplified methods that are applicable to parts of bridges with classified details and which are subjected to standard loadings;
(b) methods using first principles that can be applied in all circumstances.
The following topics are not specifically covered by this Part of this British Standard but their effects on the fatigue life of a structure may need to be considered :
(a) aerodynamically induced oscillations:
(b) fluctuations of stress in parts of a structure immersed in water, which are due to wave action and/or eddy induced vibrations;
(c) reduction of fatigue life in a corrosiveatmosphere (corrosion fatigue)
Highway loading is included in this Part and is applicable to the fatigue design of welded orthotropic steel decks. However, the stress analysis and classification of details in such a deck is very complex and is beyond the scope of this Part of this British Standard.
The fatigue assessment of certain details associated with reinforcing bars is included in this Part but interim criteria for unwelded bars are given in Part 4.
The fatigue assessment of shear connectors between concrete slabs and steel girders acting compositely in flexure is covered in this Part, but the assessment of the effects of local wheel loads on shear connectors between concrete slabs and steel plates is beyond the scope of this Part of this British Standard.
This effect may, however, be ignored if the concrete slab alone is designed for the entire local loading.
