PERFORMANCE OF UWRAP AS AN ANCHORAGE SYSTEM IN EXTERNALLY BONDED FRP REINFORCED CONCRETE ELEMENTS

Open Access
Author:
Lee, Jae Ha
Graduate Program:
Civil Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
February 16, 2010
Committee Members:
  • Dr Maria Lopez De Murphy, Dissertation Advisor
  • Maria Lopez De Murphy, Committee Chair
  • Andrew Scanlon, Committee Member
  • Bohumil Kasal, Committee Member
  • Charles E Bakis, Committee Member
  • Ivica Smid, Committee Member
Keywords:
  • Finite Element Model
  • Rehabilitation
  • Concrete
  • FRP
  • Anchor
  • Fracture mechanics
Abstract:
During the past decades, numerous studies for flexural and shear strengthening using FRP have shown good strengthening effects and durability. Many of these studies,in particular those related to concrete structures, however, have also reported a lack of ductility in the strengthened element due to premature debonding failure at the concrete-FRP interface. The possibility of preventing or delaying the premature debonding of concrete-FRP interfaces has lead to the investigation and development of new anchor systems for externally bonded FRP applications. In this study, performance of Uwrap as an anchorage system was studied. Experimental and numerical procedures were proposed to characterize the effect of the Uwrap in the performance of externally bonded FRP reinforced concrete elements (EBFS). Two key factors were found pertaining to the externally bonded FRP system with the Uwrap. The first factor is the stress concentration at the corner of the Uwrap. The stress concentration at the corner region of the Uwrap was the main cause of the rupture failure of the Uwrap. The second factor is the frictional effect between the debonded surfaces under the region of the Uwrap after the onset of the debonding. Based on these two key factors, a frictional bond-slip model of the concrete-FRP interface was proposed in this study in order to predict the anchor effect of the Uwrap. The developed FE analysis with the proposed frictional bond-slip model well predicts the bond behavior under the Uwrap locations.