KMH«K»inin jSiSj

Tandem is m\




Figure 4.2 : Load Model 1

Note : The application of 4.2.4-(2) and 4.3.2-(l) to (4) practically consists, for this model, of choosing the location of Lane 1 and the locations of the tandem systems (in most cases in the same cross-section). The length and width to be loaded by UDL are those of the relevant adverse parts of the influence surfaces.

(6) Where general and local effects can be calculated separately, and unless otherwise specified by the client, the general effects may be calculated :

a) by replacing the second and third tandem systems by a second tandem system with axle weight equal to :

Note: The relevant authorities may restrict the application of this simplification.

b) for span lengths greater than 10m|, by replacing each tandem system in each lane by a one-axle concentrated load of weight equal to the total weight of the two axles.

NOTE : The relevant authorities may restrict the application of this simplification. The single axle weight is:

- 6000CQ1 ^ on Lane Number 1

- 400gcq2 kN on Lane Number 2

- 2oogcq3 kN on Lane Number 3

(7) The values of the factors ocQj, aqj and aqr (adjustment factors) may be different for different classes of route or of expected traffic. In the absence of specification these factors are taken equal to one. In all classes, for bridges without road signs restricting vehicle weights, oqi>M and (4.4)

for : i > 2, cxqj > 1 ; this restriction is not applicable to aqr. (4.5)

Note : cxqj /aqj and CCqr factors other than one should be used only if they are chosen or agreed by the relevant authority.

4.3.3 Single axle model (Load Model 2)

(1) This model consists of a single axle load PoQak Wlth ^ak equal to l400lkN. dynamic amplification included, which should be applied at any location on the carriageway. However, when relevant, only one wheel of l200lpQ (kN) may be considered. Unless otherwise specified, |3q is equal to

(2) Unless it is specified to adopt for the wheels the same contact surface as for Load Model 1, the contact surface of each wheel is a rectangle of sides 0,35 m and 0,60m as shown in Figure 4.3.

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