As China impresses the world with its efficiency in building massive bridges, builders have found a new way to construct overpasses even faster. Workers who are building the 4,629-foot-long Xingkang Bridge in Sichuan Province have used a drone to help them install cables.
A video has emerged showing how an unmanned device flew over the raging Dadu River while carrying a pilot cable towards the bridge’s other tower.
The bridge, which costs one billion yuan (£117 million) to construct, is situated over a dangerous terrain. It crosses the fast-flowing Dadu River and is built above a valley on the edge of the Tibetan Plateau in south-west China’s Sichuan Province.
Last December, workers started putting cables on the mega structure. On April 5, the first main cable backstay of the bridge was installed, according to Xinhua News Agency.
Spanning 1,100 meters, the cable backstay is at least 269 meters (880 feet) above the Dadu River.
The speedy construction process is brought to reality thanks to an innovation method workers have used.
The video captured the moment how workers used a six propeller drone to carry a pilot cable from one side of the bridge in Kangding County to the other in Ya’an City. It took the drone three minutes to get to the other side.
The pilot cable, with a diametre of just two millimetres, was barely visible. However the thin thread, weighing 6.6 pounds (3kg), played a vital role in cable laying.
After the pilot cable reached the other side of the valley, workers attached a thicker cable to the end of the pilot rope and pulled the thicker rope over.
They repeated the process a number of times and increased the thickness of the rope each time until the rope had the strength to carry the weight of a bridge cable, which had a diameter of 54 milimetres.
According to the bridge’s chief engineer Tang Zhongbo, using a drone to lead the pilot cable has saved the team significant amount of time.
Mr Tang told Sichuan Daily that a drone is ‘100 times more efficient’ than the traditional method, which is to use a boat, a manned helicopter or a mini rocket. Furthermore, by using a drone, the workers could control where the pilot cable landed more precisely, according to Mr Tang.
The construction team also saved more than 80 per cent of the cost in laying the pilot cable, said Xu Guoting, a manager from the Sichuan Road and Bridge Group, in an interview with China Central Television Station.
The Xingkang Bridge has two cable backstays, each of them comprising 187 steel ropes. Each of the 187 ropes are made with 91 steel cables.
The installing of the first backstay this week marked the beginning of the construction of the main structure.
The Xingkang bridge is a part of an expressway that links Tibetan Plateau and Sichuan Basin.
The suspension bridge is scheduled for completion in August 2018. It will have a dual carriageway with four lanes of traffic in each direction allowing the vehicles to travel at 49.7 mph (80kmh).
Some 34,034 cables will be used in the construction, with the total length reaching 37,282 miles (60,000 kilometers) if all the cables were laid along in a single line.
Source: Daily Mail