Experts from the Expert Working Group of the Ministry of Transport: The Humen Bridge is basically stable and the possibility of vortex vibration is low

　　At around 2 pm on May 5th, significant vibration occurred on the deck of the Humen Bridge. The bridge management department quickly launched an emergency plan, and the joint traffic police department adopted two-way traffic control measures. Why does the Humen Bridge shake? Does it affect bridge safety? The expert working group of the Ministry of Transport has arrived at the scene on May 6 to carry out investigation and discussion, and responded to the media with social concerns.

Experts from the Expert Working Group of the Ministry of Transport: Humen Bridge has basically stabilized

　　After the vortex occurred, traffic control was implemented on this section, and social vehicles were prohibited. According to experts, according to the monitoring of the bridge, the phenomenon of vortex vibration gradually returned to normal in the afternoon of May 6.

Wu Mingyuan, a member of the expert working group of the Ministry of Transport and a professor at the China Communications Highway Planning and Design Institute: Actually, this afternoon (May 6) is after 12:30, basically this jitter has returned to normal, just like the past (state) It's almost the opinion of our expert meeting yesterday (May 5) night that this is caused by vortex vibration, and there will be two kinds of vibration of suspension bridges, one is called vortex vibration that will affect comfort, the other is that it will affect Bridge safety is called flutter. This time we mainly caused vortex vibration that affects comfort. It should be said that this vortex vibration will not have a big impact on the bridge structure. Of course, if vortex vibration occurs for a long time, there will be ( (Bridge) The problem of fatigue occurs, of course, we have also seen that the bridge is basically stable in less than 20 hours.

　　According to the preliminary judgment of the expert working group of the Ministry of Transport, the main reason for the shaking of the Humen Bridge is the bridge vortex caused by the continuous installation of water horses along the bridge's side rails under certain wind conditions.

Chen Airong, a member of the expert working group of the Ministry of Transport and a professor of Tongji University: After the water horse approaches the railing, the originally ventilated railing becomes a solid, and the streamlined section becomes an instreamlined section. Separation will form vortices, forming vortices one by one. It has a (vibration) frequency. When this frequency is close to the bridge's own frequency, resonance will occur. We call it vortex-induced resonance.

Experts from the Expert Working Group of the Ministry of Transport: the possibility of recurring significant vortex vibration is low

　　According to experts, the Humen Bridge uses a streamlined cross-section design, which has a small wind resistance and a low probability of vortex vibration.

Chen Airong, a member of the expert working group of the Ministry of Transport and a professor at Tongji University: The probability of occurrence is very low. The choice of the cross section of the (bridge) is better, but there is no guarantee that (it will not happen). Occurrence, this cannot be guaranteed 100%, but the possibility of occurrence of such obvious vibration is relatively low, but it is not 100%. There may be, but it will not cause safety problems.

　　Since vortex vibration occurred on the Humen Bridge at 2 pm on May 5, this section has been under traffic control. So, are there any traffic conditions now?

Chen Airong, a member of the expert working group of the Ministry of Transport and a professor of Tongji University: In terms of its own wind, from this perspective, I think there is no problem with the traffic. Even if such vibrations occur on the bridge, do n’t panic, the bridge is open. Yes, this is my point of view.

　　However, experts said that the final opening of the bridge still requires comprehensive consideration of various factors, and needs to maintain a prudent attitude. Only after the completion of the bridge inspection can the specific time for the restoration of traffic be determined.

　　(CCTV reporter Gong Haiquan Wei Xing Huang Dongxu Wu Suibin Zhao Chen)