What is a heavy vehicle pressure beam? Can a thousand-ton train be parked on the bridge to protect the bridge from floods?

what is a heavy vehicle pressure beam? Can a thousand-ton train be parked on the bridge to protect the bridge from floods?

Extreme weather such as landslides, mudslides and floods frequently occur. Every summer, many bridge decks and piers are washed away by the impact of floods. At this time, how to ensure the safety of bridges? On August 17th, 22, the flood peak of Fujiang River in Mianyang, Sichuan Province hit the Fujiang Bridge in baoji-chengdu railway. At this critical moment, a heavy cargo train with a total weight of more than 8,1 tons was pushed onto the bridge by locomotives, which is the heavy vehicle beam for flood fighting and overseas Chinese protection. What is a heavy car pressure beam?

The heavy truck beam pressing is one of the emergency schemes commonly used by railway departments in flood season. Literally, it means to press the bridge deck on it by using the weight of heavy trucks or trucks to ensure the stability of the bridge. With these extra weights, the bridge can be strengthened, and it is difficult for the flood to destroy the bridge. There are many successful examples of heavy trucks pressing beams in history. Take the Fujiang Bridge in baoji-chengdu railway mentioned above as an example. This bridge is made of steel, so the whole bridge is light in weight and has poor stability, and it is difficult to resist the impact of the flood when it happens. In order to solve the structural material shortage of the bridge, only by increasing the weight can Da Qiao compete with the flood.

In fact, it's okay when the water level of the flood is low, because only the pier will be impacted by the flood at this time, but when the water level rises to the bearing part, both the pier and the pier will be washed away by the high intensity of the flood. At this time, there is a gap between the flood water surface and the bridge, which will be filled with air, and the rapid flow of the flood will drive the air flow around the water surface. According to Bernoulli's principle, the greater the flow velocity of the fluid, the smaller the pressure, so the smaller the air pressure will cause air to accumulate under the bridge deck, forming an airbag, which will form an upward force on the bridge deck, thus aggravating the overall instability of the bridge. If the water level rises further at this time, all parts of the bridge will face the flood.

Railway bridges, in particular, are the lifeline of national transportation. Once a dangerous situation occurs, it will cause more difficulties in the follow-up. Therefore, the requirements for drivers who carry out the task of heavy vehicles and beam pressing are very high. After all, it takes not only technology but also courage to drive a train weighing thousands of tons to the railway bridge that is about to be submerged. Of course, not all bridges are suitable for heavy vehicles to press beams. Because of the light weight of steel structure, it is more likely to be washed away when the flood strikes, so most of the bridges that apply for heavy vehicles are made of this material. However, the bridge deck with concrete pouring is not suitable for using heavy vehicles to press beams because of the heavy weight of the bridge itself.