Welded steel mesh is the first steel mesh product welded in factories abroad in the early twentieth century. After nearly a hundred years of application and development, it has been widely used in the construction industry abroad, and is considered as a new, efficient, time-saving, energy-saving, reinforced concrete structure building materials.
It is mainly used in multi-storey and high-rise buildings, concrete highways, Airport runways, tunnels, concrete pipes, bridges, water conservancy, power dam foundations, wharfs, warehouses, fences and other fields. Especially in the United States, Germany, Japan, Singapore and other countries have been widely used. In addition to making prefabricated members on reinforced concrete, welded steel mesh is mostly used in cast-in-place concrete structures, and is widely used in wallboard, floor, roof and other fields of industrial and civil buildings.
2. Welded steel mesh
Welded steel bar net is a smooth or ribbed steel bar, which is made of common low carbon steel hot-rolled disc rod or low carbon steel non-twist controlled cold-rolled hot-rolled wire rod as raw material and is reduced by cold rolling or cold drawing. After straightening, leveling, leveling and cutting, steel meshes of different specifications are welded at a certain distance, as shown in Fig. 1 and Fig. 2 (abbreviated). Generally, single or double steel bars can be used for longitudinal reinforcement of steel mesh, while single steel bar can only be used for transverse reinforcement.
The welded net of steel bar can be divided into two kinds according to its shape: the welded net of steel bar and the welded net of steel bar. The spacing and diameter of steel bar of the welded net of steel bar can be different in two directions, but in one direction there are the same diameter of steel bar, the same spacing of steel bar and the same length of steel bar. The shape and size of the welded net of steel bar should be determined according to the requirement of the demander through consultation between the supplier and
Compared with the traditional bonded steel bar, the welded steel bar net has the characteristics of accurate spacing size, high strength, good stiffness, uniform load-bearing, strong crack resistance, steel saving, fast installation speed and low labor intensity. It combines the advantages of reinforcing steel bar with the factory production, so that the material properties can be brought into full play, and at the same time, the steel bar engineering can be changed from manual operation to factory production. It is understood that the original design of the maintenance project of Puji River overpass in Tianjin was the ordinary grade I steel bar binding and rolling net with a diameter of 010.0111lB and a spacing of 10mm. The comprehensive cost of the project is 1525,000 yuan, while the comprehensive cost of the project using welded steel bar net is only 1352,000 yuan, which saves the cost of the project by 170,000 yuan, 30% of the steel, 90% of the construction period and 70% of the labor.
In 1995, the Ministry of Metallurgy approved the issuance of the industry standard for welded steel mesh for reinforced concrete with YB/T076-95, and in 1997, the Ministry of Construction approved the issuance of the technical regulations for welded steel mesh concrete structures with JGJ/T114?97. In 1998, the Ministry of Construction listed welded steel mesh as the key building materials and construction industry to be popularized in the Ninth Five-Year Plan. One of the 10 new technologies applied. The above regulations provide a broad space for the development of welded steel mesh and provide a strong guarantee for improving the quality of welded steel mesh.