Seismic Damage Analysis Of Steel Fiber Reinforced High Strength Concrete Mid-Rise Shear Wall

Reinforced concrete shear wall is a common lateral force resisting component against earthquake that has been widely used in high-rise and super-high-rise buildings.The characteristics of ordinary reinforced concrete shear walls,such as small ductility and poor energy dissipation,have been difficult to meet the requirements of seismic fortification of building structures.How to improve the seismic performance of shear walls is one of the key problems in seismic design of high-rise buildings.In earthquakes,the structure of the shear walls will have different degrees of damage,and with the repeated effects of the earthquake,the damage will continue to accumulate until the structure is destroyed.The theoretical basis of structural seismic design,damage prediction and post-earthquake repair is provided by reasonable damage models.In this paper,the damage model of steel fiber reinforced high strength concrete mid-rise shear wall was established through the low-cycle repeated load test and damage analysis of six shear walls.The main research in this thesis as follows:(1)Effects of steel fiber volume ratio and concrete strength grade on the seismic performance of shear wall members were analyzed through the low-cycle repeated load tests of six steel fiber reinforced high-strength concrete mid-rise shear wall.The results revealed that with the increase of fiber volume fraction ratio,the ductility,energy dissipation and bearing capacity of the components are significantly improved,and the stiffness degradation was delayed.With the increase of concrete strength,the bearing capacity of the component was obviously improved,the energy consumption capacity was slightly improved,but the ductility was reduced and the stiffness degradation was accelerated.(2)Based on the test results of six steel fiber reinforced high-strength concrete shear walls,the effects of steel fiber volume ratio,loading cycles,loading methods and concrete strength grade on the damage performance of steel fiber reinforced high-strength concrete mid-rise shear walls were studied.The results showed that steel fiber could effectively delay the damage development,the increase of loading cycles increased the damage,the increase of amplitude accelerated the damage development,and the increase of concrete strength increased the damage under the same cumulative deformation.(3)The two-parameter damage model of steel fiber high strength concrete mid-rise shear wall was established with the comprehensive consideration of the influences of first super deformation damage and cumulative damage(cumulative energy dissipation,cumulative inelastic deformation)based on the existing damage model.The proposed model can reasonably represent the damage evolution characteristics of shear walls,which can be used to describe the damage evolution process of shear walls.