Control And Study On Cracking And Deformation Of Ladder-Reinforce Steel Concreted Beam

Ladder-reinforced referring to double reinforcement is also called modern strengthening reinforcement, which is formed to ladder-framework by two parallel longitudinal reinforcement and short transverse reinforcement plumbing longitudinal reinforcement. In theory adopting bi-steel technique can improve bonding function between reinforcement and concrete and decrease width and space of cracks of bending member, which makes cracks appear slight and dense. Applying bi-steel can saves steel and concrete.In recent years, experimental research on different bi-steel concrete beams and plates are carried in more than twenty regions in china, which widely extends the using areas of bi-steel technique. The advantages of cooperating between bi-steel and concrete have been primarily accepted. As a result, many houses introduce bi-steel and gain economic benefits.However, at present bi-steel is made from cold-drawn wire or cold-rolled ribbed steel, which can't be used in large structure with large reinforcement ratio. But be used in some structural such as small span one-way concrete slab, lintel and stairs. The study on bi-steel made ofâ…¢grades big-diameter hot rolled ribbed steel has been blanked at present in china, also in other countries. In order to take enough advantage of bi-steel and extend application, this paper generally study on the problem of welding big-diameter bi-steel withâ…¢grades hot rolled ribbed steel of diameter of 14 mm.Based on the capability of bi-steel, it still accords with work of common reinforced concrete structure. The calculation of strength can refer to current reinforced concrete standard. However the calculation of rigidity and cracking should differ from the common ones. This paper emphasizes on rigidity and cracking of bending structure with big-diameter bi-steel. Besides, the author analyzes work mechanism of bi-steel from angles of bonding mechanism, and explains the characteristic of crack developing of bi-steel structure. The calculating formulas of crack width and rigidity are presented.