Meet the 93-year-old master bridge builder
NINETY-THREE-YEAR-OLD professor Sun Jun has dedicated his life to working on China’s giant construction projects, including the QinghaiTibet highway, Three Gorges Dam, Yangshan Deep-water Port and the Yangtze River Tunnel and Bridge.
In his latest project, the Tongji University academic served as a senior adviser on the construction of the Hong KongZhuhai-Macao Bridge, the world’s longest cross-sea bridge, which officially opened on Wednesday.
Under the guidance of Sun, 64-year-old Xu Wei, a professor with the College of Civil Engineering of Tongji and Sun’s student, took over technical assistance for the construction of the bridge. Xu helped to save an enormous sum of money which a foreign architectural company wanted to charge.
The 55-kilometer bridge connects China’s southern mainland province of Guangdong with the country’s two special administrative regions. The Y-shaped construction spans over the Lingding Channel in south China.
Shanghai’s Tongji University made a number of contributions to solve major difficulties during the bridge’s construction. The expertise of the university, which is famous for its civil engineering knowledge, was involved in the construction of two artificial islands and an underwater tunnel.
“All the tasks that Tongji received during the bridge’s construction were tough issues,” said Li Yongsheng, the former executive vice president of Tongji.
The scholars and experts at the university worked out many efficient construction measures through scientific research and numerous experiments at laboratories, according to the university.
“Every time I saw Sun and other professors with the Tongji University working on the bridge, I felt at ease,” said Lin Ming, the general project manager with the project.
Lin initially invited an experienced Dutch architectural company to serve as the technical assistant for the project. The company agreed to send 26 experts but wanted to charge 150 million euros (US$171 million), according to Lin.
He then asked for help from Xu, an old friend, along with the expert team from Tongji University.
China’s innovative island building skills developed by Tongji scholar Ma Xianfeng was used to build the east and west artificial islands, covering 100,000 square meters each, to connect the bridge and tunnel sections.
The method developed by Ma and his team shortened the islands’ construction schedule to seven months from at least a year and half with conventional measures.
The method also minimized the impact of the bridge on the Chinese white dolphin, which is under first class state protection.
Under the method, 60 steel cylinders, 40.5 meters tall and with a diameter of 22 meters, were set in the seabed of the Lingding Channel. Grit was then poured into the hollow cylinders which were vibrated to condense the material into solid supportive pillars. Seawater was then pumped out from the space inside the cylinders, which became the base for the islands.
The first cylinder was placed in the seabed on May 15, 2011 and the west island was completed about four months later. The construction process of the other island was only three months thanks to lessons learnt.
Another key challenge during the construction of the mega-bridge was the 6.7km underwater tunnel, the world’s longest and deepest undersea tunnel.
Thirty-three huge immersed tubes, each 180 meters long and 80,000 tons in weight, comprise the undersea tunnel of the bridge.
The tunnel section is the world’s only deep-buried tunnel featuring complicated construction conditions with no prior experiences, said Yuan Yong, a professor with the college of civil engineering with the university.
“Experts in Japan, Europe and United States have researched the safety of immersed tunnels during earthquakes, but no achievements have been made on such a gigantic project as the cross-sea bridge,” said Yuan, who led a team to conquer the challenges of the tunnel construction.
Yuan deployed a “secret weapon” at the college, a multi point vibration experiment center, the world’s largest of its kind,