Concrete is concrete poured into the steel pipe and tamped to increase the strength and rigidity of the steel pipe. In general, we have concrete strength steel in concrete C50 or less as ordinary steel concrete; concrete strength steel in the concrete above C50 called steel high strength concrete; concrete strength CFT C100 above called steel high strength concrete.
As we all know, high compressive strength of concrete. But bending is weak, and steel, especially steel strong bending resistance, good plasticity, but when pressed easily instability and loss of axial compression capabilities. Concrete and steel in the structure will be able to combine the advantages of both, can make concrete is laterally compressed state, the compressive strength can be doubled. At the same time due to the presence of concrete, improve the rigidity of the steel pipe, which together play a role, thus greatly improving the carrying capacity. As a new steel concrete composite structures, mainly in the axial compressive force and a smaller compression eccentric member-based, is widely used in the frame structure (such as factories and high-rise).
Part of the concrete column is less and less welds, simple structure, the pedestal reserved cup often used in concrete foundation plug-foot column, which manufacturing plant is relatively simple, while the smaller component weight, lifting and transportation are more easy, very simple construction, steel and concrete columns were rolled sheet, plate thickness is not large, generally less than 40mm, and regardless of the factory site butt welding, have no difficulty. At the same time, compared with reinforced concrete columns, steel sheath having a reinforced concrete column function, the role of both the longitudinal and transverse reinforcement stirrups, so no steel tube, steel cutting and saving a series of steel banding process, and Since the column jacket pipe itself is resistant to lateral pressure template, but also save the formwork and form removal processes. In recent years, quite common pumping concrete, poured on-site no difficulty, and the creation of widely used high Paola not vibrated concrete method of construction, more streamlined site - concrete steps, simple construction. In the lower portion of the column is also open temporary watering hole with a bottom-pouring of concrete pump concrete way, not only fast, but also to ensure the quality of watering. Moreover, after pouring, steel pipe is fairly stable humidity conditions, water can not evaporate, eliminating the need for water conservation processes, simplifying the process of curing concrete.
