Excuse me, under the design load of bridges and culverts, what does the car-over 20 trailer-120 mean? thank you

There are many kinds of vehicles running on the bridge, such as cars, flat trailers, tracked vehicles and road rollers. And all kinds of vehicles have different opportunities on the bridge. The Code for Design of Highway Bridges and Culverts stipulates that standard load should be adopted in bridge design by analyzing, synthesizing and summarizing the number of axles, the distance between front and rear axles and the actual axle pressure of vehicles. Take the frequent and huge fleet as the vehicle load; Occasionally, tracked vehicles and flat trailers appear alone as the loads of tracked vehicles and flat trailers. The calculated load is automobile load, and the check load is tracked vehicle and flat trailer load.

The vehicle load is expressed as a fleet, which is divided into four grades: automobile-10, automobile-15, automobile -20 and automobile -20 or above. The figure of the load class indicates the total weight and tonnage of the main vehicle. There is only one heavy car at each level of the team, and the front and rear are the main cars. Heavy-duty vehicles refer to vehicles with large total weight under the specified load level.

Hang-120 is the check load.

Trailer 120 is a redesigned trailer fleet of 120t, and car 10 is a fleet of 10t. As for how to arrange the fleet, it depends on the general specifications of 85. The standard design axle load 100 is a single-axle two-wheeled standard car, which is used for pavement design.