Thirty-four years ago today, on January 2, 1991 (November 17, 1990 in the lunar calendar), the Nanpu Bridge in Shanghai was completed. Nanpu Bridge is the first bridge across the Huangpu River in Shanghai, and it is also a cable-stayed bridge with double towers, double cable planes and superimposed beams designed and built by China. Construction of Nanpu Bridge started on December 15, 1988, and the bridge was completed on January 2, 1991. On November 19, 1991, the inauguration ceremony of the bridge was held in Shanghai. The main bridge of Nanpu Bridge was 846 meters long, and its span was the longest in the country at that time. The lower floor of the bridge deck is made of a large "I-beam" frame, and the upper floor is a reinforced concrete bridge deck. The steel frame and the bridge deck are welded by electric welding, and concrete is poured at the joint to make the two integrated. This new type of structure in which the superimposed bridge deck and steel frame are stressed together is called superimposed beam structure. This is the first time that it has been adopted in China, which is the first in the history of bridge construction in China and a pioneering work in the history of bridge construction. Nanpu Bridge has set many firsts. There are 438 steel beams in the steel frame of the main bridge deck, one of which weighs 80 tons, the highest in the country at that time; The thickest steel plate used to make steel beams is 80mm, and its thickness is the highest in the country. The diameter of more than 100,000 sets of high-strength bolts used to assemble steel frames is 30 mm, and the size of the bolts is a record in the history of bridge construction in China. All 180 steel cables were fixed on the main tower after being pulled by jacks. The pulling force of each jack reached 600 tons, which was also the highest in the country at that time. Nanpu Bridge started construction on December 5, 1988, and it took only three years to be completed and opened to traffic in 1991. It took three years to build a long-span Nanpu cable-stayed bridge. Its grand scale, strict technology, complex technology, high construction difficulty and short cycle have created a miracle in the history of bridge construction in the world.