Evaluation of pipe rehabilitation

For this example application, the objective is to evaluate the long-term performance of FRP rehabilitation on a fully deteriorated, pressurized pipe in terms of likelihood of failure. In particular, the effects of manufacturing quality on failure probability of the as-built and service life are considered, including 

Composite thickness variation resulting from fabrication quality. 

The FRP composite is expected to resist both internal and external pressures without any contribution to the structural integrity of the system from the host pipe. It is also assumed that the pipe component is uniformly loaded and supported along its length, and the circumferential stresses are considered more critical than axial stresses (Ahmmad and Melchers, 1994 Toutanji and Dempsey, 2001 Sadiq et al., 2004). Furthermore, it is assumed that the pipe will remain at constant and uniform temperature. The total circumferential stress in the pipe wall includes the bending stresses induced by soil pressure and vehicular traffic as well as the hoop stress produced by internal fluid pressure. The total circumferential stress in the pipe wall due to loading, ag, is given as follows (Ahmaad and Melchers, 1994 Amirat et al., 2006)  

Rehabilitation of Pipelines Using Fiber-reinforced Polymer (FRP) Composites 

In this analysis a Monte Carlo simulation is conducted, where random numbers are generated for each identified random variable according to its respective probability distribution. The limit state function or performance equation for circumferential stress in FRP-composite pipes is provided as follows  

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