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Figure 4.13: Definition of loads on upstand walls

Section 5 Pedestrian, cycle actions and other actions specifically for footbridges

5.1 Field of application

(1) The effects of loads on construction sites are not covered by the load models.

(2) The uniformly distributed load qfk and the concentrated load O^k (see 5.3) are applicable to road and railway bridges as well as to footbridges, where relevant (see 4.5, 4.7.3 and 6.3.6.2(1)). However, for exceptionally wide footbridges (e.g. more than 6m between parapets) other values of these loads may be specified for the particular project, based on the considerations that have justified the choice of the width. All other variable and accidental loads defined in this section are intended only for footbridges.

(3) Models and representative values are given for verifications applicable to any limit state, with the exception of fatigue. Unless otherwise specified, no traffic represented in this section needs verification with regard to fatigue.

(4) For verifications relating to the vibration of pedestrian bridges and based on dynamic analysis, see 5.7. For all other verifications to be performed for any bridge type, the models and values given in this section include the dynamic amplification effects. The variable actions should be treated as static.

5.2 Representation of actions

5.2.1 Models of the loads

(1)P The imposed loads defined in this section result from pedestrian and cycle traffic, minor common construction loads, some specific vehicles (e.g. for maintenance), and accidental situations. These loads give rise to vertical and horizontal, static and dynamic forces.

(2) The load models defined in this section do not describe actual loads. They have been selected so that their effects (with dynamic amplification generally included) represent the effects of actual traffic. When traffic outside the field of application of these load models needs to be considered, then complementary load models, with associated combination rules, should be defined or agreed by the client.

(3) Accidental loads due to collision are represented by static equivalent loads.

5.2.2 Loading classes

Loads on footbridges may differ depending on their location and on the possible traffic flow of some vehicles. These factors are mutually independent and are envisaged in various clauses given below. No general classification of these bridges is therefore to be defined.

5.2.3 Application of the load models

(1) The same models should be used for pedestrian and cycle traffic on footbridges, on the areas of the deck of road bridges limited by parapets and not included in the carriageway as defined in 1.4.2 (denominated footways in this Part) and on the footpaths of railway bridges.

(2) Unless otherwise specified, other models should be used for inspection gangways within the structures of bridges and for platforms on railway bridges.

(3) In each individual application, the models of vertical loads should be applied anywhere within the relevant areas so that the most adverse effect is obtained.

Note : In other terms, these actions are considered to be fully free (see ENV-1991-1, 1.5.3.8 and 4.1-2(P)-(ii)).

5.3 Vertical loads - characteristic values

5.3.1 General

(1) Characteristic loads are intended for the determination of pedestrian or cycle-track load effects associated with ultimate limit-states verifications and particular serviceability verifications (see ENV-1991-1, 9.4.2 and 9.5.2, and ENV 1992 to 1995).

(2) Three models, mutually exclusive, should be considered, as relevant. They consist of a uniformly distributed load, a concentrated load and loads representing service vehicles.

(3) Unless otherwise specified for a particular project, the characteristic values given below should be used for both persistent and transient design situations.

5.3.2 Load Models

5.3.2.1 Uniformly distributed load

(1) The density of the uniformly distributed load is :

(2) However, for footbridges, unless otherwise specified, the following values should be taken for individual spans exceeding 10 m:

2 120 2 2,5 kN/m < qfm = 2,0+ < 5,0 kN/m (see Figure 5.1) (5.2)

where :

L : is the individual span length in [m].

Figure 5.1: Uniformly distributed load in relation to the span length

Note 1 : For special types of footbridges, e.g. footbridges with inclined supporting members, the span length Ls; should be defined for the particular project. The span length may be substituted by the loaded length.

Figure 5.1: Uniformly distributed load in relation to the span length

Note 1 : For special types of footbridges, e.g. footbridges with inclined supporting members, the span length Ls; should be defined for the particular project. The span length may be substituted by the loaded length.

Note 2 : Other values of qfc may be specified if they are defined or agreed by the relevant authority.

(3) For road bridges supporting footways or cycle tracks, only the 5 kN/m2 value should be considered (Figure 5.2). A reduced combination value equal to 2,5 kN/m2 may also have to be considered in accordance with 4.5.1.

Figure 5.2

5.3.2.2 Concentrated load

(1) The concentrated load Qfwk is equal to 10 kN acting on a square surface of sides |0,10| m. Where, in a verification, general and local effects can be distinguished, it is taken into account only for local effects. If, for a footbridge, a service vehicle, as mentioned in c) below is specified, Qfwk should not be considered.

5.3.2.3 Service vehicle

(1)P In the case of footbridges, when specified by the client, one service vehicle (or several, mutually exclusive) shall be taken into account.

Note : This vehicle may be a vehicle for maintenance, emergencies (e.g. ambulance, fire) or other services. It is the responsibility of the client (or of the relevant authority) to define the characteristics of this vehicle (axle weight and spacing, contact area of wheels), the dynamic amplification and all other appropriate loading rules. If no information is available and if no permanent obstacle prevents a vehicle being driven onto the bridge deck, it is suggested the vehicle defined in 5.6.3(3) be defined as the service vehicle (characteristic load) ; in this case, there will be no need to apply 5.6.3, ie. to consider the same vehicle as accidental.

5.4 Horizontal forces - characteristic values

(1) For footbridges only, the characteristic value of the horizontal force (Gfik) acts along the bridge deck axis at the pavement level and is equal to the greater of the following two values :

per cent of the total load corresponding to the uniformly distributed

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