When the full load of the sports car at both ends of the initial position, the pillars are subject to the greatest vertical stress. With a gantry that extends the arm, the pillar is subjected to maximum vertical stress when the sports car is at the end of the arm.
There are gantry cranes with extended arms that must be so that the sports car and the goods carried are free to pass through the pillars.
There are one or two out of the arm of the gantry crane, due to their weight and dynamic load born bending moment diagram and scissors map. You can calculate the braking force of the car, the friction coefficient between the wheel and the track is 0.15.
Longitudinal wind pressure of the bridge (at full load): take 20-25 kg / square meter. Due to the wind pressure and the braking force of the horizontal force (in the direction of the car track).
If we put the track track on the lower edge of the stringer and are placed on a suitable suspension mechanism, the structure of the pillar and its structure with the main Beam connection, the most simple, the most simple. This suspension is also used as a reinforcement frame to bring all the horizontal forces (mass and wind) to the horizontal link on the plane of the stringer.