不良人研究所引航官网_激情综合五月天丁香婷婷狠狠插_亚洲va中文字幕不卡无码_欧美日韩综合视频专区在线观看_小荡货芊芊小辣文NP_国产精品高中生第一次频_被强奷很舒服好爽好爽视_久久精品成人免费国产_黄色三级片免费_日韩免费中文字幕专区

Steel structure engineering is a steel-based structure and is one of the main types of building structures. Steel structure engineering is one of the more common structural forms in modern construction engineering. China was the first country to use iron to build a load-bearing structure. In the Qin Shihuang era (246-219 BC), iron was used as a simple load-bearing structure, and Western countries began to use metal load-bearing structures in the 17th century. In the 3rd-6th centuries AD, the clever and industrious Chinese people used iron chains to build iron suspension bridges. The famous Sichuan Duding River Bridge, the Yuanjiang Bridge in Yunnan and the Panjiang Bridge in Guizhou were examples of the early iron-bearing structures in China. .

Although China had outstanding achievements in iron structure in the early days, due to the shackles of the feudal system of more than 2,000 years, science was underdeveloped, so it stayed at the level of iron buildings for a long time. It was not until the end of the 19th century that China began to adopt modern steel structure engineering. After the founding of New China, the application of steel structure engineering has been greatly developed, far exceeding the past in terms of quantity or quality. It has reached a high level in the design, manufacture and installation of technologies, mastered the design and construction technology of various complex steel structure engineering buildings, and has built many large-scale and complex steel structure workshops throughout the country. Large-span steel structure civil buildings and railway bridges, steel trusses of the Great Hall of the People in China, steel grids of stadiums in Beijing and Shanghai, three-hinged steel arches of the Qin Shihuang Emperor's Horse and Horse Ware Exhibition Hall in Shaanxi and the Bird's Nest in Beijing.