Research On The Deterioration Of The Seismic Performance Of Corroded Reinforced Concrete Columns

Structures in coastal areas or in long-term acidic environments are prone to corrosion damage due to corrosion of components such as natural corrosion,resulting in weakening of structural resistance.This is due to the presence of a large amount of chloride ions in seawater.After the concrete protective layer is carbonized,the steel bars are seriously rusted under acidic conditions.As a result,the bearing capacity of the components is greatly weakened,so that it becomes brittle and the seismic performance deteriorates.In this paper,eight reinforced concrete inverted T-pillars were designed.The artificial test was used to accelerate the corrosion method to obtain the components.The combination of experiments and simulations was used to study and analyze the anti-seismic performance degradation characteristics of the flexural members under rust.It mainly includes the following aspects.Test on Stirrup Accelerated Corrosion of Reinforced Concrete Inverted T-pillar.Considering the factors such as the spacing of stirrups and the corrosion rate of stirrups,nine reinforced concrete column specimens were designed and fabricated,and the stirrups were electrified and accelerated to corrode,which in turn promoted the corrosion of longitudinal reinforcement and simulated the mechanism of natural corrosion as much as possible.The test meticulously observed the state of corrosion of the steel bar and found that the overflowing location of the corrosion product was distributed along the stirrups.The amount of rust began to increase rapidly and then tended to be gentle.The overflow of the rusted product causes the protective layer to crack,and the corner forms a major rust crack along the longitudinal tendons and a fine horizontal crack along the stirrups.The corrosion of stirrups is uneven,and the corrosion at the corners is serious.The rust in the straight section is nearly uniform,the rust in the longitudinal reinforcement approaches uniform,and the corrosion rate is small.Low-cycle reciprocating test of corroded reinforced concrete column specimens.The quasi-static reciprocating loading method was used to analyze the failure process,damage morphology,hysteresis,and energy-dissipation capability degradation of rust corrosion pressure components of rust corrosion pressure components and stirrup spacing.The results show that due to the damage of the corrosion of the stirrups to the concrete in the core region,the seismic performance of the concrete columns is degraded;when the corrosion rate is less than 15%,the bearing capacity is increased,and the shock resistance is delayed and the seismic performance is better;the corrosion rate is greater than With 30%of the components,the amount of rust in the stirrup increases,and the hysteresis curve changes from the spindle shape to the bow shape.The phenomenon of pinching is obvious,the degree of strength reduction and stiffness attenuation increase,the ductility and energy dissipation capacity decrease,and the cumulative energy consumption.It also decreases,and the above-mentioned variable increases with the increase of the amount of corrosion of the steel bar,which increases with the decrease of the stirrup interval.The corroded reinforced concrete column ABAQUS simulates low-cycle reciprocating action.According to the experimental model,the finite element modeling was carried out.The appropriate material properties,constitutive model and connection method were selected.Through the simulation analysis,the failure modes and hysteresis curves of the reinforced concrete columns and columns were obtained and compared with the data in actual experiments.Verify the feasibility of numerical simulation.