Major Structure of Pingtan Bridge Completed on 25th

At 10:28 on September 25, China's another super project - the Pingtan cross-strait road-rail bridge's major structure was officially completed. As China' first cross-strait railway bridge, the Pingtan Bridge has been much anticipated by the world because of its extremely special construction environment. The bridge is located at Pingtan Strait, one of the world's three major wind gaps as well as one of the world's famous storm tide sea areas.

According to meteorological data, every year, here, there are 314 days with winds of force 6 or above, about 220 days with force 7 winds, and about 125 days with force 8 winds.

Cheng Xiping, who was born in the 1980s, is the chief engineer of Comprehensive Work Area, First Division, Fuzhou-Pingtan Railway Project Department. He has participated in the construction of the Pingtan cross-strait road-rail bridge. Beginning from Songxia Town, Changle City, Fujian Province, the bridge passes through Renyu Islet, Changyu Islet, Xiaolian Islet and Dalian Islet, crosses Yuanhong Waterway, Guyumen Waterway, the waterways of Dalian and Xiaolian Islets, and Beidongkou Waterway successively, and ends at Pingtan Island in Su'ao Town. With a full length of 16.34 km, the bridge has a six-lane expressway on the top which is designed to support vehicles traveling as fast as 100 km/h, and a high-speed railway at the bottom, which is designed to support trains traveling as fast as 200 km/h.

In the industry, there is such a saying: "A visit to the Pingtan Bridge renders visits to other bridges unnecessary." It is talking about the high difficulty of the construction of Pingtan Bridge. The Pingtan cross-strait road-rail bridge is China's first cross-strait railway bridge. Its construction environment extremely special, as the bridge is located Pingtan Strait, one of the world's three major wind gaps as well as one of the world's famous storm tide sea areas. Here, there are 314 days with winds of force 6 or above, and typhoons visit six or seven times every year. According to Wang Donghui, the deputy chief engineer of China Railway Major Bridge Engineering Group Co., Ltd, the unit in charge of the construction, they fight against winds every day. "Every year, there are a lot of days with strong wind. According to meteorological data, there are 314 days with winds of force 6 or above. Since the construction started, from 2013 to 2019, typhoons visit six or seven times every year. Because of the special wind environment of Pingtan Strait, it is really difficult to build the bridge."

It is China's first time as well as the world's first time to build a cross-strait bridge in such a complex environment with strong winds and surging waves. Wang Donghui says: "The scale of the bridge construction is especially large. For this section of China Railway Major Bridge Engineering Group Co., Ltd, the volume of concret is 1,640,000 cubic meters and the total weight of steel used is 850,000 tons, surpassing the weight of steel used for every single bridge during their construction. The bridge is equal to four road-rail bridges of the same size across the Yangtze River. Such a big scale and such a complex and special sea area lead to unprecedentedly high construction and technical difficulty. It is one of the major difficulties in the history of China's bridge construction. This bridge, after its completion, will become a milestone of railway bridge construction."

Speaking of which, many people may ask, to build a bridge in the "bridge construction restricted zone," how to guarantee the safety of cars and trains and how to make them smoothly cross the bridge when there are strong winds? As for this question, Duan Xuewei, the person in overall charge of the design of the Pingtan cross-strait road-rail bridge and deputy director of Second Institute of China Railway Major Bridge Reconnaissance & Design Institute Co., Ltd, says: "In terms of bridge structure, we make thick piers and pile supported foundation. For example, bridges across the Yangtze River generally have a largest pile diameter of 2.8 to 3 meters, but the pile diameter of Pingtan Bridge reaches nearly 5 meters. Besides, the piers are over 40 meters deep in the sea, which can make sure the foundation is more stable and reliable. In addition, all the structures have stood wind resistance dynamic analysis test and wind tunnel test. Thus, even when there are strong winds which cause deformation of bridge structures, the track deformation and driving conditions can meet the demand of the driving comfortability. "

After Pingtan Bridge is completed, safe operation can be maintained even there are force 10 winds on the surface. Being able to finish the construction of the road-rail bridge in the "bridge construction restricted area" where there are strong winds, deep water, high waves, and inclined and exposed rock surface at the sea bottom is something really cool. Liu Ziming, the secretary of the party committee and chairman of China Railway Major Bridge Engineering Group Co., Ltd, says that the bridge looks not only cool, and importantly, its completion will make a new level of China's bridge construction technology.