Research On The Seismic Behavior Of Corroded RC Columns Under The New Restoration System

The seismic performance of the reinforced concrete(RC)structure in coastal area is seriously degraded by chloride erosion.Common SS technology cannot prevent further corrosion of steel,and ICCP can effectively prevent the further corrosion,but can not recover the influence of corrosion.Therefore,this study combined ICCP with SS,proposed a new dual repair system using C-FRCM as reinforcement material,and explored the repair effect by pseudo-static test and finite element analysis(FEA).In the test part,14 corroded RC columns were designed for quasi-static test.The main variables included axial-load ratio(0.3,0.6)and different repair methods(ICCP,SS and ICCP-SS).The hysteretic curve,skeleton curve and the ultimate strength of the repaired and unrepaired RC columns were obtained through quasi-static tests.The ultimate strength,ductility,stiffness degradation and energy consumption of RC columns with different repair methods and axial-load ratio were compared and analyzed to verify the effectiveness of the ICCP-SS repair system.Based on the test results,DIANA software was used to establish the 3D model of repaired and unrepaired columns,and the finite-element model(FEM)was compared with the test results to verify the accuracy of the FEM.Then validated FEM was used for an extensive parametric study with different corrosion rate(0%,5%,10% and 15%),C-FRCM layer(0,1,2,3,and 4)and axial-load ratio(0.3,0.4,0.5 and 0.6).According to the parametric study results,the axial-load ratio of RC columns in the coastal area should be between 0.489 and 0.652 during serviceabi lity state,and the maximum should not exceed 0.815.C-FRCM should be reinforced by layers 1,2 and 3,and should not be reinforced by layers 4 or above.Theoretical part based on the results of the tests and FEA.First verify the calculation formula of normal section bearing capacity of circular RC column is put forward by Chinese Code(GB50010-2010(2015)).And then based on the Chinese Code,the research results and the FRCM reinforcement codes AC434 and ACI549.4R,a formula for calculating the ultimate strengths of the corroded RC columns strengthened by C-FRCM is proposed.Finally,the restoring force model of C-FRCM reinforced corroded RC columns is proposed,and the accuracy of the restoring force model is verified by the test results.