NOTE Load effect from traffic mix includes dynamic factor (1 + f) defined in ENV 1991-3:1995, equation F.1.

Annex G (normative) Basis of design: supplementary clauses to ENV 1991-1 for railway bridges including serviceability criteria

To clarify Tables G.1 and G.2 and requirements G.2.3 and G.2.4 of ENV 1991-3:1995, the values for the g and c factors are given in Table G.1/2(a) for persistent and transient situations, and Table G.1/2(b) for accidental situations.

Values that differ from the boxed values in ENV 1991-3:1995 are shown in bold.

G.3.1 Performance criteria regarding deformations and vibrations

The limits of the bridge deformation for safety purposes take precedence over the limits for passenger comfort. Even if the criteria for vertical deflections for passenger comfort are conformed to, additional checks for twist, rotation, etc., shall be carried out.

G.3.1.2.1 Vertical acceleration of the deck 2) To assess the vertical acceleration of the deck, the track(s) shall be loaded as specified in Table 6.6(a). A simplified method for assessing the vertical acceleration of the deck is given in annex H.

2)P To assess the maximum permitted twist in accordance with equation G.1 of ENV 1991-3:1995, only one track shall be loaded with load model 71. For bridges that carry more than one track, the maximum twist measured over a length of 3 m shall not exceed 7.5 mm, with the tracks loaded as specified in Table 6.6(a).

This limit relates to the total twist due to any design twist that may be present if the track is unloaded (e.g. in a transition curve) and any twist due to deformation of the bridge.

G.3.1.2.3 Rotations at the end of the deck (for ballasted tracks)

1)P For double track bridges, only one track shall be loaded.

For bridges that carry more than two tracks, the criteria for double track bridges with one track loaded may be used, unless otherwise specified by the relevant authority.

(1) The consideration of the effect of wind may be required for slender structures.

(2) In addition to the partial safety factor g, the variation in depth of ballast shall be considered in accordance with 5.3.3.1(2) of ENV 1991-2-1:1995, and agreed with the relevant authority.

Key to abbreviations in Table G.1/2(a) and G.1/2(b)

— max. vert./lat.: maximum vertical and lateral effects;

— max. long.: maximum longitudinal effects;

G.3.1.2.4 Horizontal deflections of the deck To assess the horizontal deflection of the deck, the track(s) shall be loaded in accordance with Table 6.6(a).

G.3.1.3 Limiting values for the maximum deflection for passenger comfort

8)P The provisional limiting values for vertical deflection given in Figures G.3 and G.4 of ENV 1991-3:1995, and the limiting values of d/L specified in Table G.5 of ENV 1991-3:1995 shall be replaced by the values specified in Section 8 of UIC1) Leaflet 776-3R, or by values specified by the relevant authority.

In assessing the vertical deflection of the bridge, the track(s) shall be loaded in accordance with Table 6.6(a) unless otherwise specified by the relevant authority.

The span/deflection ratios are only valid for use in conjunction with load model 71, because they take into account that the load from passenger trains is less severe than the load represented by load model 71.

1) UIC, 16 rue Jean Rey, F-75015 Paris, France.

Numerical vaues for g and c factors for persistent and transient situations (excluding accidental situations)

Numerical vaues for g and c factors for persistent and transient situations (excluding accidental situations)

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