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China’s 640-Ton ‘Iron Monster’ Can Erect Colossal Bridges In a Few Days

China is bridging the world.

China’s 640-Ton ‘Iron Monster’ Can Erect Colossal Bridges In a Few Days
The SLJ900/32, aka Iron Monster, at work. Wow Joint

Launching the Belt and Road initiative in 2013, China has proven to be the heir to the tradition of the Silk Road. The project comprises land-and-sea routes that link about 70 countries, approximately two-thirds of the world.

What enabled China to initiate and carry out this project was the developed construction machines that not only expedite the construction processes but resulted in cost and resources efficiency. SLJ900/32, locally known as the Iron Monster, is a step forward in bridge construction that lifts, carries, and sets prefabricated and full-length track sections at the loaded speed of 3.1 mph (5 km/h), leaving no place for the prolonged on-site assembling process.

More than 2,000 years ago, the Han Dynasty established the Silk Road, a network of land-and-sea routes that built a bridge between the east and west transforming China into a geoeconomic center. Inspired by the Silk Road, the People's Republic of China commenced the Belt and Road initiative to link Asia, Africa, and Europe. The Silk Road Economic Belt, the on-land routes of the project, links East Asia, South Asia, Central Asia, Russia, and Europe while the Maritime Silk Road connects China's coastlands to Europe.

As the need for more land and nautical routes to complete the Belt and Road project increased, there was a demand for more progressive machines to increase the pace of this large-scale project. Therefore, Iron Monster, alongside other machinery, was invented to fulfill the goal of connecting three continents throughout a marine and land network.  

Even though critics claim this project forces Chinese debts on poorer countries setting the Chinese World Order, these inventions are still of high importance in construction engineering. Designed by the Shijiazhuang Railway Institute and manufactured by the Beijing Wow Joint Machinery Company, SLJ900/32 constructs long bridges with numerous spans at a notable speed.

One of the real-life instances of SLJ900/32 is the longest road-rail steel arch bridge project in the world: the Yibin Jinsha River Railway Bridge. Before the Yibin Jinsha, it took 12 hours to travel between Sichuan and Guizhou provinces in China, but now, the estimated travel time dropped to three hours. Another example, which is one of the several high-speed rail projects, is the one linking Inner Mongolia and the rest of the country as part of China’s vision of an 18,641.1-mile-long (30,000 km) high-speed rail.

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The bridge girdling machine moves via its 64 fully rotating wheels divided into 4 blocks. The construction process begins as it carries the beams all the way from the very edge of the bridge to the installation point, where it will be connected to a predetermined pillar. Then, using a pneumatic structure, the machine is moored to the first pillar to extend to the second one, anchoring to it, and place the beam. Afterward, SLJ900/32 continues the same steps with the new segment in tow.

Requiring much less human resources in comparison with crane-used bridge constructions, Iron Monster still requires a crew to overlook the entire process besides cleaning and maintaining its various parts. The crew's job starts as the machine sets the segment and the whole procedure repeats till the completion of the bridge.

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The machine has proven to be efficient, specifically in larger construction projects including the Belt and Road, due to the frugal use of human resources, eliminating the cost of expensive scaffolding, and the increased pace of project performance. Moreover, its 640-ton (580 tonnes) weight requires the bridges to bear more than the maximum load, which is accounted as an unexpected added value and results in more safety for the bridges constructed using this machinery.

Unfortunately, the money and technology used to build these machines should be repeated every four years for their lifespan allows them to lay about 700 to 1,000 bridge spans- the distance between two intermediate supporters for the bridge- which gives them longevity of approximately four years.

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