Info

V Ckm/h3

10 20 30 40 50 eo 70 80 90 100 110 120

Figure G.3: Successive simply supported Figure G.4: Continuous structures structures consisting of three or more spans consisting of three or more spans n * 3; b¥ = 1,0 m/s2 n * 3; bv ■ 1,0 m/s2

(9) The limiting values may also be obtained from Table G.5.

Table G.5: Limiting values 61L for the maximum vertical deflection for successive simply supported structures with n * 3, bv = 1,0 m/s2

Train speed V[km/h]

Span L [m]

L £ 15m

15< L * 30

30< L £ 50

50< L £ 90

90< L * 120

V * 120

[1/800]

[1/900]

[1/800]

[1/600]

[1/600]

120 < V 160

[1/900]

[1/1200]

[1/1200]

[1/800]

[1/600]

160 < V z 200

[1/1000]

[1/1400]

[1/1500]

[1/1300]

[1/600]

200 < V £ 280

[1/1200]

[1/1500]

[1/2100]

[1/2100]

[1/1400]

280 < V z 350

[1/1500]

[1/1600]

[1/2100]

[1/2400]

[1/2200]

The values should be multiplied by:

- a factor of 1,1 for continuous structures

- a factor of 2,0 for structures with 1 span

- a factor of 1,5 for structures with 2 spans

Note: For temporary structures the relevant authority shall specify the limiting values for the vertical deflections. The values given in Figure G.3 may be used as reference values.

G.3.2 Simultaneity of load models with other actions

(1) The rules concerning simultaneity given in G.2.1.1 are applicable. G.3.3 Combinations of actions

(1) For persistent and transient design situations the various combinations should be taken from ENV 1991-1, 9.5.2.

(2) In addition, if specified by the design Eurocodes, the infrequent combination:

j:>1 i>1 should be considered.

G.3.4 Partial factors

(1) For railway bridges, the partial factors on actions for Serviceability Limit States in persistent and transient situations should be taken as [1.0] unless otherwise specified.

G.3.S t factors for railway bridges

(1) Values of ^-factors are given in Table G.2. G.4 Fatigue

(1) The verification rules for fatigue depend on the fatigue load model to be used and are specified in the design Eurocodes.

Dynamic analysis when there is a risk of resonance or excessive vibrations of railway structures - basis of supplementary calculations

(1)P The calculations shall be made on the basis of the actual traffic crossing the structure. Where this cannot be specified exactly at least the train types 3 and 4 from annex F shall be used at the most unfavourable speed for the effect under consideration.

Note: The actual traffic to be considered shall be specified by the relevant authority.

(2) The calculations may be made using a programme for the dynamic analysis of structures under the action of moving forces.

Note: The bridge deck may be modelled as a beam (except for skewed bridges)

(3) Where an accurate analysis of the dynamic effects of the traffic is not made (using an appropriate programme or simulation based on an analytical method), the traffic may be modelled as a series of equal concentrated point forces corresponding to the average loading of the vehicles with an equivalent spacing d equal to the average length of the vehicles.

(4)P The calculations shall be made for the maximum speed as well as for speeds of:

where:

n0 is the natural frequency of the unloaded structure 40 m/s s v, s 1,2 maximum line speed.

Aj is the principal wavelength of frequency of excitation, for simplification d is the regular spacing of axles / =1,2, 3 or 4.

(5)P The corresponding increase of the stresses or deflections to be taken into account for designing the structure shall be based on the above procedures, if the effects calculated are less favourable than those calculated from 6.4.3.

Annex J (informative)

Models for rail traffic loads in transient situations

(1) Unless otherwise specified, when carrying out design checks for transient situations due to track or bridge maintenance, the characteristic values of Load Model 71 are taken equal to the infrequent values defined in Table G.2; all other characteristic, infrequent, frequent and quasi-permanent values are the same as in persistent situations.

Note: The relevant authority may specify otherwise.

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DD ENV 1991-3:2000

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