?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F37840%2F&rft.title=Numerical+Study+of+Repair+Strategies+for+Earthquake-Damaged+CFST+Bridge+Columns&rft.creator=Bumstead%2C+James&rft.description=Concrete+filled+steel+tubes+(CFSTs)+provide+a+unique%2C+economical+alternative+to+traditional+reinforced+concrete+(RC)+columns+in+highway+bridges+for+their+ease+of+construction+and+efficient+structural+properties.+The+steel+tube+provides+optimal+flexural+resistance+and+continuous+confinement+to+the+infill+concrete%2C+while+the+concrete+fill+improves+stiffness+and+strength+of+the+column%2C+and+prevents+inward+local+tube+buckling+of+the+steel+tube.+Recent+research+has+developed+a+practical+and+structurally+robust%2C+column-to-foundation%2Fcap-beam+connection+for+use+in+mid-to-high+seismic+regions.+This+connection%2C+referred+to+as+the+embedded+ring+(ER)+connection%2C+is+a+full-strength+connection%2C+where+well-detailed%2C+ER+CFST+columns+exhibit+local%2C+outward+tube+buckling+directly+above+the+foundation%2Fcap-beam+when+subjected+to+reverse-cyclic%2C+lateral+loadings.+This+typical+ductile+failure+mode+is+readily+identifiable+post-earthquake+events%2C+and+is+uniquely+advantageous+compared+to+typical+RC+columns+due+to+limited+concrete+spalling+and+the+availability+of+the+steel+tube+for+welded+connections.+%0D%0AThe+main+objective+of+this+research+was+to+develop+practical+repair+strategies+for+ER+CFST+columns+which+exhibit+this+ductile+failure+progression%2C+with+the+goal+of+reestablishing+the+original+column+strength+and+stiffness.+Two+strategies+were+developed%3A+(1)+a+traditional+plastic+hinge+relocation+method+that+utilizes+an+enlarged%2C+CFST+pedestal+that+surrounds+the+damaged+region%2C+and+(2)+a+performance-based+repair+that+implements+external+energy+dissipators+and+column-rocking+to+limit+damage.+A+non-linear%2C+numerical+analysis+approach+was+adopted+to+assess+the+hysteretic+response+of+these+repair+methods+in+comparison+to+that+of+an+undamaged%2C+CFST+column.+Results+indicated+that+both+repair+strategies+successfully+restored+lost+stiffness+and+strength%2C+specifically+peak+strength+values+of+1.26Mp+and+1.02Mp+for+the+traditional+and+performance-based+methods+were+observed%2C+respectively%2C+where+Mp+represents+the+plastic+moment+of+the+original+column.+Additionally%2C+a+limited+experimental+study+was+carried+out+on+the+proposed%2C+bucking+restrained%2C+energy+dissipator+where%2C+under+cyclic-compressive+loadings%2C+compressive+yielding+(1.12Fy)+and+inelastic+strains+(9.0%CE%B5y)+were+measured+within+the+laterally-restrained%2C+structural+fuse+of+the+dissipator.&rft.date=2020-01-28&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F37840%2F1%2FBumstead_Thesis_11.20.19.pdf&rft.identifier=++Bumstead%2C+James++(2020)+Numerical+Study+of+Repair+Strategies+for+Earthquake-Damaged+CFST+Bridge+Columns.++Master's+Thesis%2C+University+of+Pittsburgh.++++(Unpublished)++