Study On Impact Mechanical Properties Of Stainless Steel Reinforced Concrete Beams

Port wharf is a mobile hub for cargo loading and unloading,safe access and berthing of ships,in which the reinforced concrete structures in the splash and tide zones are seriously affected by corrosion.And in the course of service,it will suffer the impact of cargo drop and ship docking,which will lead to structural damage.Because of the high strength and good corrosion resistance of stainless steel,replacing ordinary steel bar with stainless steel bar can not only guarantee the bearing capacity of structure,but also solve the corrosion problem of steel bar.However,the research on impact resistance of stainless steel reinforced concrete structure is not perfect enough.In this paper,the impact mechanics of stainless steel reinforced concrete beams is studied by means of theoretical analysis,experimental study and numerical simulation.The performance of stainless steel reinforced concrete beams is studied to provide technical support for anti-impact design of stainless steel reinforced concrete beams.The main research work of this paper is as follows:1.The cumulative impact test of 12 reinforced concrete beams was carried out.The impact force,mid-span deflection,measuring point steel bar and concrete strain and other impact time-history signals were collected in the test.The crack derivation and development during impact are recorded by high-speed camera,and all kinds of data are analyzed in depth.The nonlinear dynamic finite element software LS-DYNA is used to simulate and analyze the impact of drop hammer on the reinforced raviolite beam.The numerical simulation can well verify and expand the experimental results.2.By studying the influence of reinforcement ratio on impact mechanical behavior of reinforced concrete beam,it is found that the increase of reinforcement ratio can improve the overall stiffness of the beam,reduce the deformation of the beam,and reduce the cracks and damage in a certain range of reinforcement ratio,and the influence of the reinforcement ratio on the impact mechanical behavior of the reinforced concrete beam is studied.But at the same time,there is a tendency of concrete failure from flexural failure to shear failure.3.Under the same impact energy,it is found that under the same impact energy,the impact effect of reinforced concrete beams is affected by changing the mass or impact velocity of the impact body.The impact effects of different mass and impact velocity of impact body on reinforced concrete beam are obviously different.In a certain range,with the increase of impact mass,the peak value of mid-span deflection increases first and then decreases.Compared with the impact quality,the impact velocity has a great influence on the peak value of the impact force.4.Through the study of the impact mechanical properties of reinforced concrete beams replaced by stainless steel bars,it is found that the replacement of stainless steel bars can effectively improve the overall stiffness of the beams,and the reinforcement ratio of the beams is small,and the overall stiffness of the beams can be improved effectively.The stiffness loss under cumulative impact is reduced,the elastic recovery ability is improved,the damage is reduced,and the impact resistance of beam is improved.When the reinforcement ratio is large,the strain rate effect of stainless steel bar under impact load is more obvious than that of ordinary steel bar,the bending deformation capacity of the beam is weakened,the impact energy is too late to release,and the shear failure is more serious.It is not conducive to the bearing capacity of the structure.