Experimental and numerical study on CFRP-lined prestressed concrete cylinder pipe under internal pressure

摘要

Prestressed concrete cylinder pipe (PCCP) has been widely used for water conveyance projects. However, prestressing wire breaks may result in the rupture of a pipe and cause a serious catastrophe. Application of carbon fiber reinforced polymer (CFRP) liners adhered to the inner concrete core is an effective method of internal repairing and strengthening of PCCP. In this study, a full-scale experimental test and corresponding finite element model evaluation were conducted to investigate the structural performance of CFRP-lined PCCP. In particular, the complex CFRP-concrete bonded interface was simulated by a cohesive element layer with a bilinear traction-separation response. In addition, the failure risk analysis method was introduced to determine the required number of CFRP layers for the distressed PCCP. The experimental results showed that the watertightness of liner can be improved by painting polyurea coating on the surface of CFRP laminate. It was shown by the simulation that for each additional layer of CFRP, the threshold value for the design pressure increases by 7 broken wires under the damage limit state and by 20 broken wires for the working pressure. The research presented in this paper can provide technical recommendations for the application of CFRP-lined PCCP and help utilities to better strengthen the distressed PCCP pipelines.