Experiment And Numerical Analysis Of Reinforced Concrete Shear Wall Out-of-plane Impact Resistance

Reinforced concrete structure may suffer from all kinds of impact load in the process of using,such as gas explosions,vehicle impact buildings and collisions of bridges or offshore facilities.The behaviors of reinforced concrete structures under impact load are not fully understand in the field of study,so studying the behavior of reinforced concrete structures under impact load is of great significance.In the present study,there are very few studies for reinforced concrete shear wall,as the key part of the vertical load bearing components,reinforced concrete shear wall generally does not take into account in the design of the out-of-plane stress,once wall damage may cause serious consequences.In this paper,under the impact load the dynamic response of the reinforced concrete shear wall out-of-plane was studied by means of test,finite element simulation and parameter analysis,the main research work is as follows:(1)The pendulum impact tester which the hammer weight and hammer speed can be adjusted was designed,and using the impact pendulum tester for reinforced concrete shear wall out-of-plane impact test.The design of this experiment conducted four specimens,including two cast-in-situ wall and grouting sleeve connection of prefabricated wall,the wall reinforcement keep the same reinforcement ratio.Experimental study on the dynamic response characteristics of the cast-in-situ wall and prefabricated wall under impact load,the test variable of the same wall is the impact block mass.Each measuring point of displacement,impact and each measuring point of steel and concrete strain were measured in the test,and using high-speed cameras respectively video on the central back wall,side wall and front bottom wall,exploring the development of the wall cracks under the impact load.Finally analyzed the the experimental phenomena,and summarized the characteristics of the reinforced concrete shear wall out-of-plane under impact load.(2)Based on test data and test results of other researchers,using ls-dyna software to establish the three-dimensional finite element model of multiple tests.The finite element simulation results compared with the test results,and the results show that the simulation results are in good agreement with the experiment datum,it verified the suitability and effectiveness of the subsequent numerical simulation method in this paper.(3)Using ls-dyna software analysis parameters.The 28 finite element model of 7 group reinforced concrete shear wall under impact load was established using LS-DYNA in the same method as before.The analysis of the influenced factors include the impact energy,the impact block mass,axial force compression ratio and reinforcement ratio.The results indicate that: under the condition of the same impact block mass,a linear relationship between the impact energy and the biggest displacement of the wall will be displayed.Under the condition of the same impact energy,the energy distribution proportion between the reinforcement and the concrete will be influenced by the change of the impact block mass.When the velocity of the impact block increases with the decrease of the impact block mass,concrete local damage is aggravating,reinforced absorbed energy decreases,and the decrease of deformation energy result in the displacement decreases.When the axial compression ratio is less than 0.3,axial force will increase the impact resistant ability.So under the condition of little axial compression ratio,we can ignore the axial force in the design,the results should be safe.Finally,the design based on energy is discussed,in this paper we put forward the design train of thought that using the static design method based on yield line method to resist the impact of the corresponding energy function,we summed up the design process and gave the recommended values of the parameters in the formula.