Elasto-Plastic Behavior on Seismic Retrofitting for Circular Steel Bridge Pier by Externally Bonded Carbon Fiber Sheets

Abstract

AbstractIn this study, the retrofitting effect of carbon fiber (CF) sheet wrapping method on circular steel piers subjected to cyclic loading was evaluated quantitatively using finite element analysis. To verify the accuracy of the finite element analysis model, the analytical results were compared with the experimental results obtained from the previous study. The circular steel specimen was subjected to an axial force equivalent to 10% of yield axial force and a gradually increasing cyclic horizontal load at the top of the specimen. Two retrofitting method were considered, first is the wrapping of seven layers of CF sheet before the loading of the specimen (reinforced specimen) and the latter is the wrapping of CF sheets after the specimen has undergone ultimate failure (repaired specimen). For the finite element analysis model, the column specimen was modeled as 4-node shell elements while CF sheet was modeled as 2-node truss elements. The validity of the analysis model was verified by considering the appropriate constitutive law for the steel specimen and by investigating the mode of application of the vertical loading. For the CF sheet elements, the capacity to resist compressive forces and presence of initial stresses were considered. The results showed that the reinforcement model can quantitatively evaluate the horizontal loading capacity and the buckling mode. For the repaired model, the horizontal loading capacity can be approximately evaluated as well, but is limited to the range where the horizontal displacement is small.KeywordsCarbon fiber sheetCircular steel bridge pierRehabilitationBucklingFinite element analysis