Analysis of the advantages and application prospects of large aperture square tube
Author: | Date:2017/6/16 16:05:58 | Sources:
In the construction of the workers and people in our country, the large caliber square tube has been using reinforced concrete for many years. The construction period of the project is long and the pollution is great. In recent years, with the promotion of market of hot rolled H steel, Maanshan Iron and steel products, large diameter square tube structure used in the construction industry continues to expand, a variety of experimental steel structure building, housing, buildings have been introduced, the design and construction standards and norms have begun to enter the stage of gradual improvement, the steel structure industry Chinese in recent years is a step forward. But at present our country the construction of large diameter square tube structure is mainly used for hot rolled H steel and welding of various steel structures, hot-rolled H steel in China's production capacity has reached 3 million tons, light steel H and welding steel structure production also has hundreds of thousands of tons, China about 7000000 tons a year of production of welded pipe among them, the construction steel structure with rectangle pipe and a variety of cold-formed steel production in less than 5% of the total production of cold-formed steel. The application of cold-formed steel in China's industrial building steel structure is in the initial stage. The cold-formed square rectangular welded pipe instead of hot-rolled H steel as the column of steel structure has just started, and other cold-formed steel has less application in construction industry.
The allowable deviation of the caliber of the large diameter rectangular tube should not exceed 10% of the nominal wall thickness when the wall thickness is not greater than 10mm. When the wall thickness is greater than 10mm, the positive and negative 8% of the wall thickness is, except for the corner thickness and the thickness of the weld area. The large size cold-formed large diameter rectangular pipe market has larger market space, and the reasonable number of floors of steel structure residence is 10~18 storeys. Such high-rise structure also has certain requirements for the specifications of cold-formed large-diameter rectangular pipe. A square steel tubular has obvious advantages, the same length and diameter, round tube, square tube bearing capacity and seismic better, according to the test on the three layer two cross pipe and pipe concrete column was conducted at a university in Tianjin, square tube column length 150mm, diameter 150mm, the test results before the anti lateral force the yield capacity and ultimate bearing capacity of 80% more than the latter, the seismic index is about two times of the latter.
The usual length of a large aperture square tube is 4000mm-12000mm, with the majority of 6000mm and 12000mm. The large diameter rectangular pipe allows the delivery of short and non calibre products which are not less than 2000mm, and can also be delivered in the form of interface pipe, but the demand side should remove the interface pipe when using. The weight of products with short and non calibre products is no more than 5% of the total delivery volume. For large diameter rectangular pipe whose theoretical weight is larger than 20kg/m, it should not exceed 10% of the total delivery volume. The bending degree of large diameter rectangular pipe should not exceed 2mm, and the total bending degree should not be greater than 0.2% of the total length. The construction of large square square tube is convenient, and the circular pipe concrete column in steel structure needs further construction, and the circular section is changed into square type. It is difficult to deal with the connection of circular pipe concrete and beam. In the future steel structure market in our country, the cold-formed rectangular tube will have an important share.
