Buckling Strength of a Thin-Wall Stainless Steel Liner Used to Rehabilitate Water Supply Pipelines

Stainless steel liners are being used with increasing frequency for the trenchless rehabilitation of damaged water supply pipelines in China. At present, there is little research on the buckling resistance of stainless steel liners that takes into account the realities of the insertion process into water pipelines after years of service. In this paper, the buckling strength of stainless steel pipe liners has been studied by laboratory testing of lined pipe samples. The results show that the fold-and-form method used with stainless steel liners in practice is difficult to apply and resulted in inadequate installations. Comparing the test results against existing methods for the theoretical prediction of liner buckling strength, it was found that the predictions varied considerably from the test results and they could not be applied directly to the stainless steel liners. In keeping with the results found by previous authors for different liner materials, the gap present between the stainless steel liner and the host pipe is the most significant factor decreasing the critical buckling strength. The results from the Lagrange interpolation method based on strength curves involving the gap between the liner and the host pipes as proposed in the literature were found to fit well with the test data. It is believed that, with proper estimates of the annular gap expected, this approach could be used for the design of stainless steel liners used for water pipe renewal.