Traffic Page SNiP

The values of load depend on the class of the load (K) which is defined from GOST 52748: for permanent structures K=14, for wooden bridges K=11, for structures under reconstruction K>=11 or it should be defined by the user. For railroad for capital structures K=14 and for wooden bridges K=10. But the schemes for load models with load class K=14 is different, because one of them is for road bridges and the other is for railway bridges.

Setting	Description
Upper table	The number of lanes and the particular eccentricity for each lane are calculated automatically from the input of the road way width (rww) using a default width of notional lanes of 3m for AK-1, AK-2 load models and 3.5 m for HK load model (just one input value for all lanes). However, these settings could be adjusted by the user. The lanes are distributed onto the road way from left to right, whereas using option "Mirror" will apply them also starting from the right side (default setting "Yes"). In the stage calculation of RM Bridge these two situations will then be superposed with each other.

Setting

Description

Upper table

The number of lanes and the particular eccentricity for each lane are calculated automatically from the input of the road way width (rww) using a default width of notional lanes of 3m for AK-1, AK-2 load models and 3.5 m for HK load model (just one input value for all lanes). However, these settings could be adjusted by the user.

The lanes are distributed onto the road way from left to right, whereas using option "Mirror" will apply them also starting from the right side (default setting "Yes"). In the stage calculation of RM Bridge these two situations will then be superposed with each other.

AK-1 load model

AK is a set of bands each of which consists of vehicle with two axles and uniformly distributed load. The load on each axle is P=10K kN and the uniformly distributed load is v=1K kN/m. If there is more than one lane, the load should be multiplied on the coefficient s1, which equals to 1.0 for axle loads and 0.6 for uniformly distributed load.

Setting	Description
Load class (K)	class of the load which as default for this type of structure is 14.
Axle load (P)	load on axle and calculated as 10K kN.It can be seen in the plot as the red point load and automatically updated when the load class K is changed.
Uniform load (v)	uniformly distributed load and calculated as 1K kN/m.In the plot it is divided by the lane width.
Lane factor	uniform load multiplication coefficient for more than one lane.
Axle distance	distance between load train axles.
Pedestrian load	Consider pedestrian load (Yes/No) defines whether the pedestrian load shall be considered or not. Intensity left/right and eccentricity left/right defines the intensity and the eccentricity of the linear distributed load on the left and right side of the roadway.

AK-2 load model

In AK-2 pedestrian load is not consider anymore,traffic load is distributed on the whole deck width and 2 lanes are always working together as a group so even number of lanes is required for definition.They can be then together mirrored or moved in any other position.

Setting	Description
Load class (K)	class of the load which as default for this type of structure is 14.
Axle load (P)	load on axle and calculated as 10K kN.It can be seen in the plot as the red point load and automatically updated when the load class K is changed.
Uniform load (v)	uniformly distributed load and calculated as 1K kN/m.In the plot it is divided by the lane width.
Lane factor	uniform load multiplication coefficient for more than one lane.
Axle distance	distance between load train axles.

HK load model

HK is the load from the heavy vehicles and tracked vehicles as 4-axle truck with the load 18K on each axle.

Note: For calculating the bridges for HK, the verification on double HK loads should be made. They should be made with the distance of 12 meters (between the last axle of the first truck and the first axle of the last truck). Also, reduction factor should be taken into account, it equals 0.75.

Setting	Description
Load class (K)	class of the load which as default for this type of structure is 14.
Axle load (P)	load on axle and calculated as 18K kN.It can be seen in the plot as the red point load and automatically updated when the load class K is changed.
Double vehicle	(Yes/No) defines whether double vehicles shall be considered or not.If yes the a reduction factor of 0.75 is taken account when calculating Axle load P.
Axle distance	distance between load train axles.
Pedestrian load	Consider pedestrian load (Yes/No) defines whether the pedestrian load shall be considered or not. Intensity left/right and eccentricity left/right defines the intensity and the eccentricity of the linear distributed load on the left and right side of the roadway.