On September 25, 2019 (August 27, 2019 lunar calendar), our country's first cross-sea highway and railway dual-purpose bridge closed. At 10:28 on September 25, 2019, the last section of the steel truss with a length of 17.5 meters, a width of 36.8 meters, a height of 15 meters and a weight of 473 tons was steadily lifted to the design elevation by the girder crane. The successful closure of the Guyumen Channel Bridge, one of the three main channel bridges of the Pingtan Strait Highway and Railway Dual-purpose Bridge, marks the world's longest cross-strait highway and railway dual-purpose bridge designed by the China Railway Bridge Institute and constructed by the China Railway Bridge Bureau, and the first cross-sea highway and railway dual-purpose bridge in our country - the Pingtan Strait Highway and Railway Dual-purpose Bridge. It is understood that the Pingtan Strait Road-Rail Dual-purpose Bridge has a total length of 16.34 kilometers. It starts in Songxia Town, Changle City, Fujian Province, passes through Renyu Island, Changyu Island, Xiaolian Island, and Dalian Island. It crosses Yuanhong Waterway, Guyumen Waterway, Big and Small Lian Island Waterway, and North Dongkou Waterway in turn. It arrives at Pingtan Island in Su'ao Town. There are three steel truss combined girder cable-stayed waterway bridges, including Yuanhong Waterway, Guyumen Waterway, and Big and Small Lian Island Waterway. Among them, Yuanhong Waterway Bridge and Big and Small Lian Island Waterway Bridge have been closed on June 5, 2019 and December 28, 2018, respectively. According to Gao Zongyu, the chief engineer of the China Railway Bridge Institute, the Taiwan Strait where the bridge site is located is one of the three famous storm waters in the world. The sea environment is complex, with strong winds, high waves, rapid currents, and hard rocks. The wave force is more than 10 times that of the Yangtze River and other inland rivers. The annual wind above level 6 exceeds 310 days. The construction conditions are harsh, the effective operation time is short, and the construction is extremely difficult. It can be called a "bridge construction restricted area". In the construction of the Pingtan Strait Road-Railway Dual-Use Bridge, the China Railway Bridge Bureau has successfully solved a series of problems in bridge construction under harsh and complex marine environment conditions, accumulated experience in design, construction, supervision and construction management, and formed a complete set of technologies for the construction of road-railway dual-use bridges in complex sea areas. This has important reference significance for similar bridge projects in the future, and also makes the Pingtan Strait Road-Railway Dual-Use Bridge a new milestone in the history of bridge construction in our country. It is understood that the Pingtan Strait Road-Railway Dual-Use Bridge started construction in November 2013 and is expected to be fully opened to traffic in 2020. It is a key control project for the new Fuzhou-Pingtan Railway and Changle-Pingtan Expressway. The upper layer is designed as a six-lane expressway with a speed of 100 kilometers per hour, and the lower layer is designed as a double-track I-class railway with a speed of 200 The closure of the Pingtan Strait Highway and Railway Bridge has laid a solid foundation for the opening of the Fuzhou-Pingtan Railway and the Changle-Pingtan Expressway. After the bridge is opened to traffic, the time and space distance between Fuzhou and Pingtan will be greatly shortened, and Ronglan will form a half-hour "economic life circle", which is of great significance for speeding up the connection between Binhai New Town and Pingtan Comprehensive Experimental Island, which integrates the three national-level strategies of "Free Trade Zone, Pilot Zone and International Tourism Island", and promoting the economic development of Haixi. (Zhang Jingyu, correspondent of Huang Jin, China Traffic Radio correspondent, China Central Radio and Television Station)