LRFD Approach to CFRP Renewal of Prestressed Concrete Cylinder Pipes

Carbon fiber reinforced polymer (CFRP) composites are being used increasingly for renewal of prestressed concrete cylinder pipe (PCCP), due primarily to its easy and speed of installation requiring no excavation of the pipe. Experience in developing probability-based limit states design (PBLSD) criteria for common construction materials points the way forward for making similar advances in guidelines for design and evaluation of PCCP renewal using CFRP composite materials. This paper is aimed at providing technical basis to support such a standard development. The paper reports progress made on developing the PBLSD approach for CFRP renewal of PCCP. Reliability tools and supporting databases that are available for developing the load and resistance design (LRFD) criteria are summarized. A set of load combinations for underground pipe design that are consistent with the modern probability-based load modeling concepts are proposed. The LRFD design formats for pipe strength limit states are presented in a relatively simple, practical and familiar form to facilitate the implementation of CFRP composites in concrete pipeline renewal practices.