Let the world further understand Made in China! The new version of Chinese standards has attracted international attention!

It is the 2nd anniversary of the official release of the new version of the national standard for prestressed steel strand GB/T 5224-2023 "Steel Strand for Prestressed Concrete"!

This batch of national standards involves multiple fields such as intelligent manufacturing, basic raw materials, urban construction, and ship environmental protection. The release of this batch of important standards will play a positive guiding role in promoting the intelligent green upgrade of the industry, consolidating the foundation for industrial development, and promoting high-quality economic and social development. The national standard GB/T5224 "Steel Strand for Prestressed Concrete" was first released in 1985. For more than 30 years, it has accompanied the development of the prestressed products industry. It is the guiding basis for product production inspection, engineering design, and construction acceptance. It is an irreplaceable and important basic standard in the prestressed steel strand industry.

Prestressed concrete strands are the core material of prestressed concrete structures and play an important role in bearing. The products are widely used in national railway and highway bridges, water conservancy and hydropower, rock and soil anchoring, coal mine support, high-rise buildings and other national key engineering fields. In recent years, they have also been widely used in new energy fields such as nuclear power, LNG, and wind power.

The current national standard has been revised for nearly 10 years. During this period, prestressing technology has developed rapidly, and higher requirements have been put forward for the use span and material strength of prestressed concrete structures in engineering. In particular, Europe, the United States, Japan, South Korea and other countries have continuously strengthened their research on ultra-high-strength prestressed concrete structure technology. In 2020, the new version of the international standard ISO 6934-4:2020 "Steel Strand for Prestressed Concrete" also included ultra-high-strength prestressed steel strands in the standard scope. In recent years, some manufacturers in my country have also successfully developed 2160MPa, 2230MPa and 2360MPa grade steel strands and applied them in projects on a trial basis. At present, my country has made breakthrough progress in the research and development and production of ultra-high-strength steel strands, and the market demand for low-strength steel strands of 1470-1670MPa in the current national standard is already very small. Therefore, improving the strength level of prestressed steel strands has become an important direction for the revision of this national standard. Including ultra-high-strength steel strands in the scope of national standards is conducive to promoting the joint research and development of engineering design units and raw material wire rods, anchors and other production enterprises, and will have a positive impact on promoting the overall improvement of the industrial chain, promoting the technical quality of ultra-high-strength steel strands, and realizing the engineering application of larger spans and lighter structures, and will achieve huge economic and social benefits. In addition, 1×19 structural steel strands were included for the first time in the 2014 version of the national standard. After nearly 10 years of development, the application of this product in the field of coal mine support has formed a scale advantage. The current standard for the tensile strength and test methods of 1×19 structural steel strands can no longer fully meet the user's demand for the product. The new version of the standard has revised and improved the size measurement method, lay length, tensile strength and other contents of 1×19 structural steel strands.

At the same time, the new version of the standard also adds the variety and specification of "1×7 structural spiral rib steel strand" and "fatigue performance of steel strand for inclined cables", reflecting the concept of "product innovation standards first". In combination with the use of users, the elastic modulus of prestressed steel strands and the minimum effective clamping length of tensile tests are stipulated, and the provisions of test methods such as "correlation coefficient for calculating 1000h relaxation rate" and "measurement method of nominal weight deviation per meter" are added. The national standard "Steel Strand for Prestressed Concrete" has a very high industry influence. This revision work has been highly valued by the Wire Rod and Steel Wire Sub-Technical Committee of the National Steel Standardization Technical Committee, and has also received strong support and active participation from the Metallurgical Industry Information Standards Research Institute, prestressed steel strand manufacturers, engineering design units, and raw material wire rods and anchor manufacturers. Together, efforts have been made to improve the standard level of products and fully meet user needs. The new version of the standard fully reflects the experience of my country's prestressed product industry in the production and use of prestressed steel strands. The technical indicators of the standard are advanced and reasonable, scientific and operational. After review and evaluation by the expert group, it has reached the international advanced level.