Program computes braking load due to each live load case generated if selected in the live load generation dialog. As per clause 214.2 from IRC, (6), for a single or two lane bridge, program considers 20% of the first train load plus 10% of the load of the succeeding trains. Program considers full train effect even if the train is partially loaded on the span. In case of more than 2 lanes loaded, in addition to effect as mentioned for 2 lanes loaded, it considers 5% of loads in lanes in excess of two. Impact factor is not considered for these loads but multiple lane reduction factor as stated in clause 208, IRC (6) is applied.

The braking force shall be taken as greater of:

C = 25% of the axle weights of the design truck/tandem, or

This longitudinal force acts at 1200 mm from the deck/roadway and is parallel to the traffic direction. (Along Z for Substructure.)

The total longitudinal load is distributed among all the bearings/girder locations as bearing loads. The moment about the X axis is applied as cap load and the moment computed about Z axis is applied as a force couple in Y direction at exterior bearings. If there are two bearing lines, half of the force is distributed on bearings in each bearing line. For skewed bridges, Substructure resolves the load into X and Z components resulting in bearing loads in both X and Z directions of the pier.

This generation internally accounts for the pier view direction and then generates loads as per the view direction.

In case of skewed bridges, Substructure calculates the appropriate force and resolves it into X and Z components appropriately. The moments generated about X axis are applied as cap load whereas the moments generated about Z axis is applied as couple on the exterior bearings/girders. If the pier is non-integral and has two bearing lines then each line will resist half of the moment which is then divided by the distance between the first and the last bearing to generate the force in Y direction.