Reporter

I began research on bridge ship collision impact and bridge seismic resistance during my doctoral studies. That was at the beginning of this century, when domestic research in the field of bridge ship collision had just started. In those years, China experienced several ship-bridge collision accidents, including the well-known 2007 ship collision accident at the Jiujiang Bridge in Foshan, Guangdong, and the ship collision accident at the Jintang Bridge, among others. These accidents attracted great attention from the engineering community at the time, and at that time China had no corresponding codes to guide design in bridge ship collision, so when I was writing my graduation thesis, my supervisor Professor Wang Junjie suggested that I conduct research in the field of bridge ship collision impact.

In my thesis, I mainly analyzed how to assess the ship collision risk of bridges, how to calculate the response of bridge structures under ship collision, and proposed corresponding active and passive protection measures to minimize losses. After starting work, I was also very interested in this direction and have been engaged in related research in this field ever since.

Reporter

Xiamen-Zhangzhou Sea-Crossing Bridge

In response to these characteristics, we conducted in-depth research on bridge vibration reduction and seismic resistance. At that time, domestic design experience for sea-crossing bridges in high-intensity seismic zones was not particularly extensive. Based on investigating the design, construction, and management experience of many similar bridges at home and abroad, especially in Japan, we adopted many seismic isolation measures for the bridge, including lead-core seismic isolation rubber bearings with a capacity of 2,500 tons, the largest tonnage in China at that time. These seismic isolation bearings have now been in use for 16 years, and their effect on enhancing the seismic resilience of the entire bridge is very good.

Lead-core rubber bearings

In addition, regarding bridge ship collision, because of the high navigation density, the planned navigable tonnage for the North Channel Bridge is about 30,000 tons, and for the South Channel Bridge it is 5,000 to 8,000 tons. The safe passage of such large-tonnage vessels poses a great challenge to bridge collision protection. Based on multiple considerations and practical needs, we developed a steel boxed cofferdam for both construction and collision protection, which was the first case in China at that time. This steel boxed cofferdam can be used during construction and can also be converted into a protective structure during operation, playing an important role in improving the bridge's collision resilience.

Reporter

"Resilience" is a term originally introduced from abroad. What is the connotation of "resilience"? For bridges, it means, first, the ability to resist disasters, and second, the ability of the bridge structure to recover quickly after a disaster. To enhance a bridge's ability to resist disasters, we can work on the structure, for example by installing seismic isolation devices or devices to prevent ship collision. We can also consider strengthening the structure or adding redundancy measures to ensure that after a disaster the bridge does not collapse or interrupt traffic and cause more serious consequences, and that traffic can be restored quickly.

China's infrastructure peak came later than abroad. Around the 1970s and 1980s, many developed countries abroad had already passed their construction peaks, while China's infrastructure peak came after 2000, especially between 2005 and 2020, when many large-scale infrastructure projects were built. In the early stage of China's infrastructure peak, many design concepts related to "resilience" were borrowed from European and American codes.

But now, with the continuous development of China's bridge technology, we also have many of our own development ideas and concepts.

After the construction peak, many bridges will enter the maintenance and operation stage. How to ensure the safe operation of existing bridges is a very important research direction. China has made relevant preparations in three aspects. First, the research and development of new materials, that is, developing and using new materials that are lighter, stronger, and more corrosion-resistant to improve the strength and durability of bridge structures and enhance their ability to resist natural disasters. Second, research on new structural systems, adding resilient structures or details in bridge structural system research so that bridge structures do not suffer cascading collapse when responding to disasters. Third, in the operation and maintenance process, introducing many monitoring and early warning methods related to artificial intelligence so that immediate response can be taken once an accident occurs, avoiding very serious secondary damage. These are all important aspects that we need to continue to focus on in the bridge field in the future.

Reporter

Intelligent construction is currently a very popular direction and also a future development trend. To better promote intelligent construction, I believe efforts are needed to achieve breakthroughs in three aspects.

The first is the policy level. National policy support or guidance is needed, because promoting intelligent construction requires substantial upfront investment, which may cause initial costs to rise, for example in building "intelligent construction factories" or "smart factories." But once scale or established patterns are formed, costs will drop significantly.

The second aspect is the standards and codes level. Corresponding technical specifications are also needed to support the adoption of prefabricated or intelligent construction. If we regard bridges as industrial products, the corresponding standards and codes need to be further improved and perfected; otherwise, it is still somewhat difficult to define by what standards products produced in factories should be introduced to the market.

The third aspect is the practical level. At present, many bridges have already adopted prefabricated structures during construction, and the use of these structures has achieved very good results. However, at the current stage of using prefabricated technology, one issue everyone is very concerned about is still cost. The situation may be better in the relatively economically developed areas of southeastern China. But in the western region, the application of prefabricated structures is lower, and without large-scale replication and promotion, it is very difficult to reduce costs. Therefore, if a province or a region can carry out overall planning and plan and build some standardized beam yards or factories to cover a certain range and bring down costs, prefabricated construction will have great room for development and application.

Intelligent beam yard of the Beijing-Hong Kong-Macao Expressway reconstruction and expansion Section 5 project

Reporter

The laboratory where I work was originally called the State Key Laboratory of Bridge Engineering Structural Dynamics. In 2019, in response to the requirements of the Ministry of Science and Technology, it underwent reorganization, which took three years to complete. After reorganization, it was renamed the State Key Laboratory of Bridge Engineering Safety and Resilience. The laboratory is led by China Merchants Chongqing Communications Research & Design Institute Co., Ltd., and jointly supported by Academician Chen Zhengqing's wind resistance team at Hunan University and Academician Du Xiuli's seismic resistance team at Beijing University of Technology. The three parties complement each other's strengths and form a full-chain system of industry, academia, research, and application. The institute represents "industry" and "research," and the two universities represent "academia"; doing this well together is "application." In the process, enterprises pose the questions and raise practical demand issues in bridges, and the laboratory solves them, jointly bringing the laboratory's scientific research results to the market and truly leveraging the advantages of the full-chain system of industry, academia, research, and application.

Innovative equipment system for bridge inspection and assessment

Relying on the operation of the laboratory, we have incubated many enterprises, covering cable development, steel bridge deck paving, bridge collision protection, bridge inspection, bridge monitoring, bridge maintenance and repair, and many other aspects. If the laboratory is a platform, then in the process we have professional R&D teams doing the corresponding R&D work. When subsidiary companies face the market, they feed back the problems they encounter, and then the laboratory conducts R&D and improvement to solve these practical problems. After technological upgrading and iteration, we then bring new products or new equipment to the market, thereby forming a virtuous cycle mechanism in which research promotes production and production supports research, ensuring the operation of the laboratory.

Reporter

Everyone has clearly felt that China's infrastructure market is now in a period of contraction, but the existing stock market is enormous. Take bridges as an example: China now has 1.2 million existing bridges, the largest number in the world. How to ensure the operational safety of these 1.2 million bridges is a very arduous task for the future. At the same time, China has a vast territory and complex service environments for bridges, such as the marine climate environment in the east, the permafrost environment of the western plateau, and the wind-blown sand environment of the northwestern Gobi. In addition, natural disasters occur frequently in some regions, and the probability of bridges being hit by strong earthquakes, strong winds, floods, and impacts is very high, all of which bring great challenges to bridge operation and maintenance.

The main positioning of our laboratory is to solve problems of disaster prevention and mitigation of bridges under typical dynamic loads such as earthquakes, strong winds, and impacts, as well as long-term performance monitoring and assurance throughout the life cycle.

The country is now formulating the "15th Five-Year Plan," and one important aspect is the operation and maintenance of transportation infrastructure. Our laboratory is actively making preparations in the two fields of intelligent disaster prevention and intelligent operation and maintenance. At the same time, our team is leading the compilation of many standards and codes, including the Ministry of Transport industry standards "Design Specifications for Highway Cable-Stayed Bridges" and "Specifications for Seismic Design of Highway Bridges." It can be said that these will play an important role in enabling China's bridge industry to make steady and long-term progress.