Steel structure with light weight, short construction period, adaptable, attractive appearance, convenient maintenance, etc., its application more widely. The development of steel and steel production are closely related. China has become the world's major steel producing countries, steel production in China in 2005 has exceeded 300 million tons, of which the output of steel up to 1.4 million, energy, transportation, metallurgy, machinery, chemicals, power, construction and infrastructure areas such as steel industry has become the backbone of the national economy.
Since the 80s from the 20th century, the Chinese construction steel structure has been an unprecedented development, construction steel structure construction in the national economy plays a very important position. Basis to evaluate the amount of steel in 2005, about 11,550,000 tons of steel building steel structure, compared to 836 million tons in 2002, 38%%. At present, China's steel structure, steel structure, bridge steel structure, light steel structure residential steel and other industrial and civil construction, are springing up all over the country. According to statistics, so far, China has built more than 60 high-rise buildings high-rise steel buildings; large span steel structure in a variety of stadium, exhibition centers, theaters, terminals, hangars and a number of industrial plants in the application; steel bridge in the ascendant, 90 years after the last century, according to incomplete statistics, only to Shanghai in the Yangtze River in Yibin, the number has reached more than 50 已建和在建 Tower Bridge, where more than half a bridge, "a lot has been among the 'world class' bridge, demonstrating the contemporary construction of the bridge has reached the world advanced level of technology "; After several years of further research and development into the steel structure house has a new stage of development, a group of the Ministry of Construction of the demonstration project, pilot projects and The key technology research projects have been completed and made achievements in scientific research, in the "recycling economy" "green building" and other policy guidance, the future of steel residential construction will flourish.
Characteristics and difficulties of steel welded construction
Looking at the current status of building steel structure engineering and development trend, more and more with modern architectural style and architectural features of high technology, and its main features are:
1. Novel and unique shape, structure, system range, the node structure is complex, multi-form welded joints, component production and field installation of the welding technology more and more difficult. For example: the National Stadium "Bird Nest" a large number of complex steel structure truss columns, the main truss, secondary structure of welded joints, weld criss-cross, the construction is very difficult.
2. Building height high, large span structures, earthquake resistance design of the main steel structure, high quality requirements. Such as: frame beam and column connection weld connecting the shear plate and column weld, the beam web connection with the column and the column weld seam stitching, are the main parts of the structure, basically Singapore population penetration level of weld, 100% ultrasonic testing, welding quality requirements are very high.
3. Use of varieties of steel specifications, and more and more tend to use high-strength low-alloy structural steel and large thickness of the steel, iron and steel production process level with the continuous improvement of cast steel, stainless steel, composite steel has also been more An increasing number of applications. Therefore, the required on-site before the construction of the steel used for the delivery of state of affairs, a new real-time test for welding steel, welding parameters to explore science, welding technology to develop appropriate measures.
4. Factory production and field installation link to many factors, many different types of cross-operation, on-site installation difficult.