Study On Seismic Test For Seismic Damage Concrete With Prestressed Steel Strand Reinforced Concrete

The rapid maintenance and reinforcement of bridge pier after the earthquake and the emergency recovery of shear bearing capacity,the necessary research content of seismic reinforcement is to be restored as soon as possible.The prestressed steel strand reinforcement method is used in the repair and reinforcement of bridge pier with its construction speed and economic advantages.At present,the research on the seismic reinforcement effect of prestressed steel strand is mainly carried out on the intact pier,while the reinforced pier column in the actual project has a certain amount of damage.Therefore,it is needed to further study the seismic performance and shear design theory of reinforced concrete pier with prestressed steel strand.The research contents and corresponding research results of this paper mainly include the following aspects:(1)Quantitative pre-loss and reinforcement of reinforced concrete specimens:according to the existing model of Park-Ang classic damage model,some parts of the specimens are pre-damaged to varying degrees.The concrete column specimens are strengthened by a new set of prestressed steel strand reinforcement with the same research team.(2)To different damage degree of the reinforced concrete columns of the comparison of the seismic performance: the damage of concrete column strengthened with different methods in the pseudo-static test failure pattern,hysteresis curve,bearing capacity,deformation,stiffness of the test result analysis,get the following conclusion: the effect of any: compared with the ordinary unreinforced columns,the failure modes of reinforced column from the shear failure to bend shear type damage;When the bearing capacity of the damaged column can be restored to the undamaged,the shear bearing capacity decreases with the increase of the damage degree.Any defined according to the experiment,the D?6.0 secondary damage specimens using(S=100,a=0.1)way of reinforcement can overcome the influence of damage on seismic attenuation performance of specimens,and for any higher specimen,can increase prestress degree to improve the reinforcement effect.The influence of the spacing of the steel strand: due to the influence of the height of the plastic hinge area,the change of the spacing of the steel strand has little impact on the bearing capacity.The influence of prestress degree: prestress degree is an important factor influencingthe effect of seismic reinforcement.The ductility of the specimen,carrying capacity and energy dissipation capacity increase with the increase of prestress degree.(3)The damaged concrete column strengthened with prestressed steel strand of shear bearing capacity of the theoretical study: sorting the existing nondestructive concrete column strengthened prestressed steel strand calculation method and formula of shear bearing capacity,combining with the test data,the formula of shear bearing capacity of prestressed steel strand reinforcement column is optimized,the damage of steel strand work and influence coefficient is put forward.The calculation formula of shear bearing capacity of reinforced damaged concrete columns with prestressed steel strand is obtained.