Study On New Composite Reinforced Concrete Structure And New Crack Controlling Method On "Release-Prevent" Principle

The reinforced concrete (RC) beam has poor anti-crack property, as a result its rigidity and durability are weakened and spanning ability limited. In order to improve the RC beams'performance, the new composite concrete beam based on fracture mechanics is proposed, which contains interface-bonded anti-crack reinforcing GFRP layers as well as embedded steel rebars. Massive tests and study, as well as the mathematical simulating method make it clear that the crack properties are improved, the ultimate carrying capacity is promoted extremely higher than that of the RC beam, the new beam's after-cracking rigidity is enhanced obviously in comparison with the RC beam and the failure ductility also improved.For the sake of exploring mechanic performance of the new structure, and the engineering application, the large size beams were tested to validate the excellent mechanic performance.The core content of the thesis is to validate the excellently mechanic performance, at the same time, based on the anti-crack enhancing mechanism of the new composite concrete structure and the"release-prevent"principle of the crack controlling, a new structure concept is proposed.The experimental and finite analysis show that the size effect on the new composite concrete beams is weak and the optimal scheme of the new structure is the beam with GFRP anti-crack enhancing layers in U type, which apply the hard-steel rebar.