China Net Commentator: Qi Yibin Yang Xinhua
Editor in charge: Tang Hua Jiang Xinyu
The "storm" of Humen Bridge has been touching people's hearts recently.
originated at around 14:00 on May 5, and the suspension bridge deck of Humen Bridge experienced obvious vibration. In order to ensure driving safety, the bridge then closed two-way traffic and had not resumed traffic by May 9.
netizens' moods also swell. Whether the Humen Bridge can still be walked, collapsed, and have design defects has become a hot search on the Internet for a long time. There are also some doubts that lack scientific knowledge and factual basis, including imagination. Some commentators do not know what "water horse" is, but are actively making speculative remarks that "the bridge has building quality problems."
After research and consultation by well-known domestic bridge experts, the main reasons for the vibration of the bridge have been clarified. The popular explanation of the "storm" of Humen Bridge is: the "water horse" set up by Humen Bridge for construction and maintenance turns the originally air-ventilated railing into two rows of solid low walls, which is equivalent to changing the appearance of the bridge and changing the resonance frequency of the bridge. At this time, a suitable wind speed happened to be encountered, which triggered vortex vibration.
It should be noted in particular that the suspension bridge design adopted by Humen Bridge, as a flexible structure with a large span, is very sensitive to the effect of wind loads and is prone to wind vibration response. This is the weakness of suspension bridges, but its advantages are also very clear: suspension bridges are the form of bridges with the largest leap capability in the world; there is relatively high passage space under the bridge deck; it has strong adaptability to deformation and is suitable for areas with complex geological structures, etc. Therefore, suspension bridges are economical and appropriate choices in a construction environment that spans the strait.
"Maybe everyone is shocked from the video, but it seems very normal in our opinion." , professor of the Department of Bridge Engineering of Tongji University, said in an interview with reporters on May 6 that judging from the monitoring data, the vortex amplitude of the Humen Bridge this time will definitely not exceed the design standard, and it is much lower than the standard. "The bridge has no structural safety issues, nor has durability issues."
At present, the Humen Bridge bridge has basically stabilized, and nearby waters have also resumed navigation. After a comprehensive inspection of the bridge's main cable steel wire, main cable slings, support and other structures, all parts were in good condition. The preliminary analysis results of the Guangdong Provincial Earthquake Bureau also show that the main structure of the bridge box girder was not significantly affected in this incident.
Ge Yaojun is a famous bridge structure expert in China, chairman of the International Association for Bridges and Structural (IABSE), and the first Chinese scholar to be elected as chairman of the International Bridges Association. After abnormal movements occurred on Humen Bridge, he participated in a video conference on collective analysis held by 12 bridge experts that night.
Recently there was a video circulating on the Internet, which was a speech by Ge Yaojun. He started with his teacher and the "Bridge Family" of Tongji University, and reviewed the difficult journey of China's independent bridge construction. It mentioned the Shanghai Nanpu Bridge , which was built in 1988, is the "first shout" of Chinese bridge experts to the whole of China's independent bridge construction.
At the end of 1991, the same year that the Nanpu Bridge was completed, Li Guohao, the supervisor of Professor Ge Yaojun and academician of the two academies, learned that Guangdong Humen would invite British companies to bring funds to build the Humen Bridge, and wrote a letter to Ye Xuanping, then governor of Guangdong Province, saying that Humen is the national humiliation for Lin Zexu to ban smoking, and it is difficult for the Chinese people to accept the feelings of a British company to build the Humen Bridge. In 1997, the Humen Bridge built by the Chinese themselves took five years to complete, fully opening the history of "Made in China" of China's bridge. The name of this video is "After the completion of the Humen Bridge, there is no need to ask the source of the Chinese bridge."
Humen Bridge is not only a major transportation route across the Pearl River and connecting Guangzhou Dongguan , but also a tribute project for the return of Hong Kong, but also a symbol of the Chinese "stand up" in the field of bridge construction. If we know more about the birth process of Humen Bridge and the history of bridge construction in China, we will be more confident in it.
This cross-sea bridge standing on the Lion Ocean at the Pearl River Estuary is a national key project with an investment of nearly 3 billion yuan and is also my country's first large-scale modern suspension bridge in the true sense. Chinese engineers made innovative breakthroughs in design and construction, winning it with the Zhan Tianyou Civil Engineering Award, and several technologies won the Guangdong Provincial Science and Technology Progress Award and the National Science and Technology Progress Award. All of this established its special status in the history of our country's bridges.
The more important the project is, it will inevitably require scientific demonstration, careful design and strict construction. The design plan of Humen Bridge has undergone the most rigorous mechanical calculations and wind tunnel test verification. In 1993, the design department commissioned Peking University and Tongji University and other units to conduct experimental research on the cross-section wind tunnel of steel box girders, and the results showed that its aerodynamic performance was good.
Facts are better than words, and suspense is always answered in time. Nearly 23 years since its opening in June 1997, it has experienced many strong typhoons during this period, and the Humen Bridge has not experienced serious abnormal vibrations, which is enough to prove that the bridge design structure is safe and reliable.
So, the vibration brought by the water horse to the bridge is just a trouble of "the old revolution encounters new problems." But some clever logic often brings online speech to the edge. Some people mobilize their inertial thinking to raise questions about "whether tofu project is it?" Some self-media accounts sell pseudoscience in the name of popular science, and some netizens who "do not know the truth" spread rumors, which made people panic for a while. Some people even compare the Humen Bridge with the Tacoma Strait Bridge in the United States, which was blown down by the wind in 1940, which is very confusing.
In the online world where mud and sand are mixed, we must believe in science even more. Science and technology are real knowledge, and they cannot be faked or rumored. Bridge engineering and wind engineering involve multiple professional fields such as aerodynamics , engineering mechanics , materials mechanics, etc. The analysis and judgment of bridge experts and engineers can give more credible answers. Ignoring science and profession and unwilling to believe in authoritative experts and official releases, letting the gossip lead the nose will only keep us away from wisdom and reason and lose to paranoia and extremes.
Scientific explanation of the collapse of the Tacoma Bridge in the United States is because of flutter rather than vortex vibration, which is caused by the intricate aerodynamic and structural analysis, and is incomparable to the Humen Bridge.
can be more confident about China's bridges and China's infrastructure. The confidence of experts and engineers in the Humen Bridge comes from the history of Chinese bridge architecture that has been taken step by step, as well as the wisdom and courage poured into countless pioneers. Over the past 40 years of reform and opening up, China's bridge construction has been advancing rapidly. In recent years, the Hong Kong-Zhuhai-Macao Bridge , one of the "Seven Wonders of the Modern World", has stunned the world. With world-class bridges completed, China has also risen from a bridge power to a bridge power.
Today, my country has built more than 800,000 large-scale highway bridges and more than 200,000 large-scale railway bridges. Among the top ten large-span beam bridges, arch bridges, cable-stayed bridges and suspension bridges in the world, China occupies half of the world. Whether it is quantity, scale, technological content, whether it is domestic construction or overseas construction, China Bridge has become a well-known world brand with its high strength and majestic momentum. Faced with such a "report card", we can be more confident about China's bridge security.
The new crown epidemic in China is subsidence, and people's lives return to daily life. If we take stock of the experiences and lessons left by this arduous blocking battle, there are at least two things: one is to maintain awe of science, and the other is to remain vigilant about "habitually unconfident." When observing the "storm" of Humen Bridge, these two points also apply.
especially the second item. From a historical perspective, China has been undergoing profound changes, especially now. Although it still has shortcomings and can withstand the troubles of the thugs, time has changed, after all, it is no longer the poverty, weakness and difficulty that year. Whether it is the anti-epidemic war or the construction of bridges, it reflects the country's scientific and technological level and comprehensive strength. The strong social mobilization capabilities reflected in major natural disasters and major public emergencies are the unique resource endowment of this socialist power.If you realize this, you will not be frightened if you have any slight disturbance.
From then on, no source is asked. This is a pride and a kind of concentration.
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