Known as “The Roof Of The World”, the Tibetan Plateau covers 970,000 sq miles in Central and East Asia. It is the world’s highest and largest plateau, and until recently traveling through the region has been very difficult. The roadways that wind through the mountain ranges were poorly made. Qi Quanliang was a veteran bus driver along the Sichuan-Tibet highway. He recalls just how difficult traveling along the roads could be. He said, “The roads were either paved by dirt or small stones, which made the bus very bumpy and prone to bursting tires. Sometimes we had to spend the night in the middle of nowhere.” A trip that should only have taken a few hours could take nearly a day to complete. But as the Tibet Autonomous Region has become more reliant on tourism and goods from the rest of the world, highway conditions have greatly changed. Quanliang commented, “Only veteran drivers dared to challenge the highway in my time. But today, even a fresh hand is not afraid of it.”

Besides providing the region with better paved highways, more bridges have been built to connect the plateau to the rest of China. Perhaps one of the most famous bridges from this part of the world is the Luding Footbridge that was built during the Quing Dynasty and opened in 1701. In 1935 soldiers of China’s Red Army used the Luding Bridge to cross the Dadu River, securing it as a vital crossing point against the Chinese Nationalist Forces. Today the bridge remains a historical landmark connecting the provinces of Guizhou and Sichuan. But just as Tibet’s Yakang (Ya’an to Kangding) Expressway needed to be modernized, the bridge system needed an update too. And it is only fitting that one of the most unique regions of the world will have built a truly unique suspension bridge.

The new bridge crossing the Dadu River is called the Xingkang Bridge or Luding Yaye Expressway Bridge. Construction on the bridge began in 2014 and was opened to the public in 2018. With a deck that reaches 935ft above, and spanning 3,600 ft across the Dadu River it is both one of the tallest and longest bridges in the world. Building this massive suspension bridge was an engineering feat, and to assist in getting things done the engineering team decided to use a tool that had already been used successfully in the completion of two other bridges in China. Construction on the Longjiang Bridge in Yunnan was completed in 2016, and in 2017 construction was completed on the Xingkang Bridge in Sichuan. To see that these two bridges were completed in a timely and reliable manner engineers trained construction teams to use drones.

One of the most critical aspects of building a suspension bridge is in the laying of the support cables. Typically to do this construction teams will transport cables by boats with cranes, helicopters, or mini rockets launched from one point to another to connect the cables. But engineers knew there was a better way to connect the 34,034 cables needed for the Xingkang Bridge. They connected a length of cable to a drone and flew it from one support to the next where a worker could simply reach up to grab the hovering drone, disconnect the cable, and send the drone back to go again. Each cable the drone carried, a pilot cable, had a diameter of 2mm and weighed just over 6lbs. This cable is then used to easily pull over a thicker cable. The process is repeated until a cable that is thick and strong enough to support the bridge’s weight load is assembled.

This method proved an excellent choice as it saved the construction team countless hours and money. Each drone trip took only 3 minutes to complete, allowing the construction team to spend 80% less than average in the cost of cable laying. For a bridge that cost £117 million to build, that 80% goes a long way. Chief engineer for the construction of the Xingkang Bridge, Tang Zhongbo said that using drones to lay cables is “100 times more efficient” than the traditional methods by boat, helicopter, or rocket.

With the bridge completed, commuters can now travel through the region with greater ease. Traffic congestion has been reduced from 6 hours down to 3 hours. Though it is not a perfect system yet, it is still a start. After finding just how quickly, safely, and efficiently drones could help in building a bridge to this magnitude there will surely be further road planning projects in the future. Though vastly different than the original Luding Bridge with whom it shares a name, the Xingkang Bridge or Luding Yaye Expressway Bridge is serving a similar purpose. Bringing accessibility to people throughout Central and Eastern Asia.

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