Hunan University Bridge Technology Innovation Helps National Major Engineering Construction

Hunan Daily All Media Reporter Yu RongIn recent years, Hunan University has made significant technological innovations and contributions in the field of bridge engineering, involving the theory and control technology of wind induced vibration of flexible bridges, new eddy current damping technology, and the new system of UHPC high-performance bridge structures. These innovations not only lead the development of industry technology, but also have been successfully applied in multiple major domestic and foreign projects, obtaining a series of domestic and foreign awards and recognition

Hunan Daily All Media Reporter Yu Rong

In recent years, Hunan University has made significant technological innovations and contributions in the field of bridge engineering, involving the theory and control technology of wind induced vibration of flexible bridges, new eddy current damping technology, and the new system of UHPC high-performance bridge structures. These innovations not only lead the development of industry technology, but also have been successfully applied in multiple major domestic and foreign projects, obtaining a series of domestic and foreign awards and recognition.

Focusing on Vortex Vibration of Suspension Bridges to Make Suspension Bridges "Calm Down"

There is no absolute rigid body in the world, and seemingly indestructible reinforced concrete bridges can also undergo deformation and vibration. The flutter and vortex vibration of bridges are the two most important issues in the wind resistance of large-span bridges.

How to make suspension bridges "calm"? Hunan University has made multiple innovative achievements in wind resistance theories and technologies such as bridge flutter and suspension bridge vortex vibration, solving various wind induced vibration problems. Among them, the suspension rod high angle of attack flutter theory fills the international gap, and the multi-stage vortex vibration theory and application of suspension bridges are at the leading international level.

In 1992, a multimodal single parameter automatic search method for three-dimensional flutter analysis was proposed internationally, and a fully CNC three degree of freedom forced vibration test system was developed that can accurately identify all flutter derivatives. This solved the problem of stable, fast, and accurate calculation of critical wind speed for flutter of large-span bridges; The corresponding core technologies have been introduced and applied by Tongji University. In 2006, a 3D flutter analysis module was further developed in ANSYS commercial software, which completely solved the problem of universality in flutter analysis and has been widely applied by peers both domestically and internationally; In 2008, the theory of large angle of attack wind induced flutter of rigid suspension rods for arch bridges was established, filling a gap in structural wind resistance design. The international peer evaluation results represent the latest level of wind resistance research on arch bridge suspension rods.

(Wuhan Yingwuzhou Yangtze River Bridge adopts a tower beam direct damping vibration reduction system for vortex vibration control)

(Multi modal Wind-induced Vibration Control Project for Extra Long Stay Cables of Sutong Yangtze River Bridge)

The achievements of Humen Bridge, Jiangyin Yangtze River Bridge, Sutong Yangtze River Bridge, Aizhai Bridge, Zhoushan Xihoumen Bridge, Hangrui Expressway Dongting Lake Bridge... have been successfully applied in a number of major bridge projects in China, and have won three second prizes of the National Science and Technology Progress Award, two second prizes of the Natural Science Award of the Ministry of Education, one second prize of the Technology Invention Award of the Ministry of Education, and one first prize of the Hunan Province Technology Invention Award, Three first prizes of the Hunan Provincial Science and Technology Progress Award have made important contributions to China's bridge and wind engineering research from technology introduction to gradual surpassing.

Stabilize Bridges with Eddy Current Damping Technology

As early as the early 21st century, research in the field of vibration reduction for large-span bridges in China was still in its infancy. Several early bridges spanning the Yangtze River were plagued by vibration problems to varying degrees, and domestic companies did not have the corresponding design and manufacturing capabilities for large dampers. All products could only rely on imports from German and American companies. However, these large oil pressure dampers imported from abroad often fail due to oil leakage due to mechanical friction after 3 to 5 years of use, which not only requires a large amount of money for maintenance and replacement, but also poses a threat to the safety of major infrastructure.

Oil dampers are a technology introduced from abroad and have encountered substantial difficulties in suppressing bridge vibration. We should seize the opportunity to develop new technologies with fully independent intellectual property rights, allowing the Chinese people to make a new contribution in the field of engineering structural vibration reduction. Aiming at this major issue that needs to be urgently solved in practical engineering, Chen Zhengqing from Hunan University led a team to embark on the "road to overcoming difficulties" through systematic and in-depth research, Successfully applied permanent magnet eddy current damping for vibration reduction and buffering of large structures.

(1000t eddy current damping TMD of Shanghai center Building)

They have developed a series of eddy current damping technologies, including plate type eddy current damping units, as well as various eddy current tuning mass damping devices such as large stroke, low frequency, and micro, to meet the performance needs of different industries. In addition, they also invented a rotating tube type axial permanent magnet eddy current damper, with a maximum damping force exceeding 2000kN and a maximum axial velocity exceeding 1m/s, meeting the seismic requirements of high intensity areas and reaching the highest international level. They also innovated various special forms of eddy current dampers, developed optimization design methods for eddy current TMD topology, and innovated electromagnetic thermodynamic dynamic coupling simulation and parameter optimization design methods for high-speed nonlinear characteristics of permanent magnet eddy current dampers, achieving the highest energy consumption density of eddy current damping devices internationally.

(Developed series of eddy current tuned mass dampers)

The team has jointly developed 12 series of eddy current dampers in 3 major categories, which are widely used in large engineering projects both domestically and internationally, and have gradually replaced high-end imported oil dampers. They have incubated the national high-tech enterprise that is the first domestic household appliance eddy current damping technology. The eddy current damping and vibration reduction technology has been successfully applied in major domestic and foreign projects such as the Jiangyin Yangtze River Bridge, Sutong Yangtze River Bridge, and Moroccan Noor III solar collector tower. In the past three years, the direct economic benefits have exceeded 400 million yuan, and it has won the first prize for technological invention in Hunan Province in 2020 and the second prize for technological invention in the Ministry of Education in 2014.

Using "trendy" high-performance technology to "treat" bridge diseases

Bridges connect the great rivers of China from north to south, playing an important role in promoting the improvement of China's transportation network and economic and social development.

However, after entering the year 2000, the problem of steel deck defects in long-span bridges has been frequent. For example, steel bridge decks are prone to fatigue cracking, which usually occurs within less than 10 years; The asphalt pavement on steel bridge decks is extremely prone to damage and requires frequent maintenance, leading to a surge in the cost of bridge deck renovation.

The R&D team of Hunan University has addressed this issue and, through years of research and engineering practice, adopted materials such as ultra-high performance concrete (UHPC) to develop innovative high-performance bridge structures represented by steel UHPC lightweight composite deck structures, steel UHPC low rib composite beams, unidirectional prestressed thin-walled UHPC box beams, and prefabricated UHPC bridges, solving key technical problems.

Ultra High Performance Concrete (UHPC) is a cement-based composite material with ultra-high toughness and ultra-long durability, which is expected to solve the problems of bridge deck cracking, huge energy consumption, and short service life. For the new bridge, this is the "vaccine" for the disease, while for the old bridge, it is the "good medicine" for the cure.

(New deck combination structure and engineering application of the Shanghai Sutong Yangtze River Bridge)

They first proposed a lightweight composite bridge deck structure of steel thin layer ultra-high toughness concrete (STC), which significantly improves the local bending stiffness of the bridge deck, effectively reduces the risk of fatigue cracking, and converts steel bridge deck asphalt pavement into economical concrete bridge deck pavement. This technology has been successfully applied to multiple domestic and international large-span steel bridge projects, achieving significant socio-economic benefits.

Hunan University has also independently developed STC materials specifically for steel bridge decks and established intelligent construction equipment, greatly improving construction efficiency. They conducted over a thousand model tests, providing theoretical and methodological support for the design and calculation of lightweight composite bridge deck structures.

(New deck combination structure and engineering application of Hangrui Dongting Bridge)

These innovative bridge structure new systems have been widely applied to more than 100 domestic and foreign bridge projects, including the Shanghai Sutong Yangtze River Bridge, the Hangzhou Rui Dongting Bridge, the Wuhan Junshan Yangtze River Bridge, the Yichang Yangtze River Bridge, the China Malaysia Friendship Bridge, and the Hanoi Shenglong Bridge in Vietnam. They have achieved huge economic benefits and saved a total life cycle cost of 16 billion yuan. The research and development achievements have won the first prize of the 2017 Ministry of Education Technology Invention Award and the first prize of the China Highway Society, and have been selected into the Major Science and Technology Innovation Achievement Database of the Ministry of Transport.

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