Study On The Mechanical Properties And Restoring Force Model Of Innovative Resilient Rocking Columns

To achieve performance restoration of structures after major earthquake,an innovative resilient rocking column(IRR column)technology is proposed.Previous experimental studies have shown that the IRR column has excellent seismic performance and can be quickly repaired after damage.In order to further understand the force transfer mechanism of the IRR column and propose the corresponding design method,research based on finite element analysis was carried out.The main work completed is as follows:(1)Refined three-dimensional finite element model of the IRR column was established using FE software ABAQUS.Data of IRR columns tested before were used to verify the established FE model through the comparison of strength,stiffness,ductility,hysteresis characteristics and stress-strain state of the specimens.(2)The verified FE model was used to carry out parameter analysis of the IRR columns.The influence of the damper thickness t and the axial compression ratio n to the strength,stiffness,deformation performance,hysteretic performance and self-centering performance of the IRR columns was studied.It was shown that,with the increase of the damper thickness and axial compression ratio,the load carrying capacity of the specimens increased linearly.The residual deformation of the IRR column decreases rapidly with the increase of axial compression ratio,and the self-centering performance is thus significantly enhanced.(3)The load transfer mechanism of the steel slit dampers is closely related to horizontal loading direction.The dampers arranged parallel to the loading direction mainly resisted the horizontal load through tension,compression,flexure and shear of the damper struts.This is the main resource of the column strength,stiffness and energy dissipation capacity,with the proportion of the strength contribution being 82.3% to 90.8% of the total.The damperperpendicular to the loading direction is mainly subjected to flexure and torsion on the damper struts,which makes the contribution of the dampers to the column strength,stiffness and energy dissipation capacity much more less than that of the aforementioned dampers.The proportion of strength contribution is only 4.2% to 12.7%,approximately.(4)The maximum load carrying capacity of the IRR column was calculated by a simplified method and the plastic limit analysis method.The comparison with the FEM results shows that the results of the plastic limit analysis method are in good agreement with the FE results,and the simplified method is much conservative.However,considering the simplification of the equation,this simplified method is used and modified based on FE analysis for the use of engineering design.(5)Based on the results of FE analysis,the load transfer mechanism and hysteresis characteristics of the IRR column are analyzed.Restoring force model of the IRR column is finally proposed.The hysteretic curves calculated by this model agrees well with the test and FE results.