Experimental Study On Shear Behavior Of High-strength Concrete Beams With High-strength Steel Under Concentrated Load

High-strength concrete has the advantage of high-strength,small deformation and good durability.Replacing ordinary concrete with high-strength one in buildings could reduce the use of concrete resource,decreasing carbon-emission,which meets the requirement of energy-saving and emission-reduction.The size of components made of high-strength concrete,such as beams and columns,is usually smaller than ordinary one,making it possible to reduce the structure’s weight and increase the functional space.It is worth to promote high-strength concrete in building structures.China began to study on the preparation of high-strength concrete in 1970 s.Not until 1980 s,the research and application of high-strength concrete was done widely in China.Compared to other countries,our country have fewer achievements of high-strength research as well as its engineering application.It is suggested that we should have more research results of high-strength concrete to improve the concrete structure design code and to promote the use of high-strength concrete in civil engineering.Due to the complexity of the shear failure of reinforced concrete beams,has not yet formed a recognized shear failure theory system,at present most countries(including China)specification formula mostly in the ordinary concrete beams on the basis of the experimental data obtained,when using high-strength steel and high-strength concrete,Whether the current specification is safe for high-strength reinforced concrete beams,to be further study,And then put forward a proposal for the shear failure of high-strength reinforced concrete beams.In this paper,the shear failure of 5 root high-strength reinforced concrete beams is tested,through centralized load down test to observe the crack development process of beam,and according to the failure modes of experimental phenomena and data of the beam to analyze inclined crack,deflection and steel stress,also discussed the effect of different concrete strength and reinforcement ratio on the ultimate bearing capacity,coMPared the test of bearing capacity with softened truss model theory value and between Chinese and American codes of the calculated values.The results show that the failure process of high-strength concrete beam is similar to ordinary concrete beam,that of load-carrying capacity with the increase of concrete strength is a certain proportion of the increase,the stirrup ratio increase can increase the load-carrying capacity and ductility of beam;shear compression failure test beam bearing force and softening truss model theory value and the standard calculation values are close,bending shear failure test beam bearing capacity is higher than the calculated value,when the shear span ratio was 2.6 of high-strength concrete(C100)beam for standardization of our country on the whole still apply,the United States standard security reserve were higher than the norm.Based on the data of this experiment and the relevant test data,A formula for the failure of high strength concrete beams with high strength and high strength is presented.Finally,ANSYS software was used to carry out nonlinear finite element analysis of 5 specimens of this experiment,and the results of simulation and experiment were coMPared,and the results were in good agreement.