Yangtze bridge stands the test of time

Nanjing structure has special meaning for Chinese.

In the more than three months since it reopened to the public after repairs, more than 70,000 vehicles a day on average have crossed the Nanjing Yangtze River Bridge in Jiangsu province.

The number of vehicles traversing the bridge, which reopened in December, is just half that for each of the other three structures spanning the river in Nanjing, while Line 3 of the city's subway system carries more than 800,000 people across the river every day.

But despite its relatively meeker traffic flows, people from across the country visit Nanjing just to see the bridge, especially during holidays. For many, it represents far more than just a river crossing.

For years, it has been featured on a variety of posters and in school textbooks. Many people have had their pictures taken at photo studios that use images of the bridge as backdrops.

Hotels, cinemas and daily necessities have been named after it. Parents have even named their children after the bridge, with some of those born in the 1960s and 1970s being called "Yangtze", "Bridge" or "Pier" in Chinese.

The national landmark has received thousands of visitors from China and overseas since it opened in 1968. Leaders from more than 70 countries and over 600 delegations from 150 nations have visited it.

During the three days it reopened to the public before taking road traffic in December, the bridge had more than 200,000 visitors.

The 4,589-meter-long structure reopened after 27 months of repairs. As China's first home-designed road and rail truss bridge, it has been praised and loved by many. A truss bridge is one whose load-bearing superstructure is composed of connected elements forming triangular units.

Liu Yong, 63, a retired teacher from Nanjing, said he was in elementary school when the bridge first opened. Without telling his parents and teachers, he and his classmates walked more than 10 kilometers to see it.

"It was the most magnificent structure I had ever seen. When our relatives visited Nanjing, we took them to see the bridge instead of visiting other well-known places of interest," Liu said.

Zhou Lei, who lives in a residential community near the bridge, said that when he was an elementary school student in Yancheng, Jiangsu, his father promised him that he would take him to see the bridge if he had high scores in his final exam.

"It was such a huge temptation that I studied like crazy to get such scores. I got extremely high marks in the end, but my father failed to keep his promise because the family could not afford the tickets to go to Nanjing," Zhou said.

"Visiting the bridge had been my dream for many years. Now, my two sisters and I have all moved to Nanjing, the provincial capital. It's a happy coincidence that my family lives near the bridge."

Lu Andong, a professor with Nanjing University's School of Architecture and Urban Planning, said the bridge represents the collective memory of several generations and has special meaning for Chinese.

"It employed the country's most advanced technologies and talented workers when it was built. It was unique in stimulating cohesion and pride in the whole country," Lu said.

In 1960, the bridge featured in the Guinness Book of World Records as the world's longest with dual road and rail functions.

In 2014, it was listed as an Immovable Cultural Relic under State Council-designated protection, and two years later as part of China's 20th century architectural heritage.

Yang Tao, director of the Nanjing Institute for Urban and Transportation Planning and Design, said it was extremely hard to build the rail section of the bridge because of limited skills and technologies.

"But many bridge-building technologies were subsequently invented and these have not become outdated, even today. Completion of the bridge has played an important role in the economic and cultural exchanges between areas north and south of the Yangtze, and even unified governance of the country," Yang said.

People had dreamed of building a bridge spanning the Yangtze for years.

In 1908, the rail line from Shanghai reached Nanjing. The rail link between Tianjin and Nanjing's Pukou district - the Tientsin-Pukow Railway - was completed in 1912. But the two lines could not be connected because there was no bridge across the river.

According to the Academy of Sociology, which was founded by scholars from Nanjing University, at least two structures - the Wuhan Yangtze River Bridge and the Chongqing Baishatuo Yangtze River Bridge - were built before the Nanjing structure. But neither was considered a landmark by the public.

In 1913, Zhan Tianyou, who was known as "the father of China's railways", traveled to Nanjing to inspect the Yangtze riverbed to build a bridge. However, he dropped his plan because the river had an average width of 1,500 meters, was more than 70 meters at its deepest and the water flow was 3 meters per second.

Zhan reportedly stayed for a few days, left without saying a word, and then decided to inspect the river in Wuhan, Hubei province, before completing the first design for the Wuhan Yangtze River Bridge.

Revolutionary leader Sun Yat-sen once suggested that an underwater tunnel should be built to connect the railways in Nanjing, but his dream was not realized for about 100 years. In 1929, Sun's casket was transported to Pukou district along the Tientsin-Pukow Railway before being ferried to downtown Nanjing.

In 1930, John Alexander Low Waddell, a 76-year-old Canadian who was a traffic consultant to the Chinese government, said the Yangtze in Nanjing was too deep and was flowing too fast to construct a bridge, according to the Academy of Sociology.

The government launched large-scale investigations in 1936 and 1946 before dropping the plan. In 1956, the State Council, China's Cabinet, proposed constructing the Nanjing Yangtze River Bridge.

To test the bridge's load-bearing capacity, Xu Shiyou, who commanded the Nanjing Military Region, ordered an armored regiment to drive 118 amphibious tanks on the newly built structure at 8 am on Sept 25, 1969.

The tanks lined up, were kept 50 meters apart and stretched for 10 km, making it a memorable scene for a generation.

In October 2016, the bridge was closed for repairs after being open for almost 50 years. The 100,000 vehicles it carried each day far exceeded its designed capacity of 8,000, causing many cracks to appear in the structure. It has been repaired 12 times since 2002.

Other problems it faced included falling mortar and metal fatigue. The government decided to spend more than 1.1 billion yuan ($164 million) on the repairs.

The structure's original concrete deck was replaced by a steel one, which is lighter and has greater durability. The replacement work was carried out above the 27,000-volt railway line. Any falling material, even a screw, would have caused a power failure and disrupted services on the busy Beijing-Shanghai Railway. Workers had to erect scaffolding and protective nets when no trains were passing.

The diameter of the lamp bases on the bridge were reduced by 5 centimeters, making the sidewalk wider and more convenient for pedestrians.

Broken and missing cast iron sculptures have also been repaired and replaced. Some 202 of them, including images of sunflowers, landscapes, workers and soldiers, have been placed on the two sets of railings on the bridge to maintain its original appearance.

Guo Jian, deputy director of the Nanjing Center of Public Project Construction, said the bridge could be used safely for another 100 years if properly maintained.

"The comprehensive examination before the bridge was closed showed that it was in its prime," he said. "The bridge has been reliable for years, even after several ships collided with the piers. The flow of traffic and the speed of vehicles have far exceeded the original design but have not affected its solidity."

Yang, from the Nanjing Institute for Urban and Transportation Planning and Design, said the bridge will continue to serve as a major road, rail and marine structure.

"It has been a witness to and participant in the country's 40 years of fast development. It will greatly help the economic and traffic development of Nanjing, the province and the country," Yang added.