Research On Deformation Recoverability Of Fe-based SMA-reinforced Concrete Shear Walls

Concrete shear wall structure due to its excellent stiflness to resist lateral force,good stability,occupies very an important position in high-level structures.The shear wall structure deformation ability has directly and greatly influence on the seismic performance of the entire structure.However,many shear wall structures are questioned due to weak deformation performance and poor recoverable ability.How to improve the recoverable deformation ability of concrete shear wall structures is a kind of challengeable issue and possible research development direction in the field.The recoverable function structure system is a new type of seismic vibration control structure,which has the characteristics of quick recovery without repair after the earthquake or just with a small amount of repair.The recoverable deformation shear wall structure is one of the typical recoverable function structures.According to the review of superelastic shape memory alloy(SMA)at home and abroad and the characteristics of shear wall structure,the dissertation aims at proposing a new kind of SMA concrete shear wall structure with a good recoverable deformation capacity through summarizing the working mechanism and advantages as well as disadvantages of the SMA-based concrete beam,column and shear wall structures,and designing a superelastic SMA-based concrete shear wall structure considering the characteristics of shear wall structures.Iron-based SMA(Fe-SMA)has a low material cost and it can play an important role in concrete beam,column and shear wall structure,etc.The Fe-based SMA may have a wide application prospect in the recoverable deformation structure field.Through placing two groups of vertical Fe-SMA reinforcement in edge components of the shear wall structure,four Fe-SMA based concrete shear walls and two ordinarily reinforced concrete(RC)shear walls were designed and tested under quasi-static loading,aiming at investigating the working mechanism and influencing law of different Fe-SMA reinforcement ratio,stirrup ratio and other parameters on the recoverable deformation performance and the seismic performance.By means of the concept of the restoring force ratio at the balance position,the recoverable deformation property of shear wall structure can be well represented.The test results show that the recoverable deformation of the Fe-SMA based shear wall specimen increased 21.7%by compare of the ordinary steel shear wall specimen,and the recoverable deformation performance can be increased by appropriately placing the Fe-SMA reinforcement in concrete shear wall.The finite element method(FEM)was adopted in this dissertation to further study the recoverable deformation performance of the Fe-SMA based concrete shear wall structure.First of all,several kinds of common SMA superelastic constitutive relation were introduced in this paper,and the history of the various models and the derivation process was preliminarily described.Then,the superelastic SMA constitutive relation proposed by Liang and Rogers was written into the ABAQUS by using FORTRAN.Finally,the Fe-SMA reinforced concrete shear wall structure was numerically analyzed by using ABAQUS under the quasi-static loading.Both of the experimental results and simulation ones proved that the recoverable deformation ability of the shear wall structures can be effectively improved by appropriately placing the Fe-SMA reinforcement in concrete shear wall by compare of common reinforced concrete shear wall structure,and the SMA reinforcement ratio and the stirrup ratio in edge components of the shear wall has a great influence on the recoverable deformation ability.