| The ultimate limit state of circumferential buckling of plastic manholes or pipes under ground and fluid loads was previously unknown. A new test facility was constructed and experimental procedures were developed to test high-density polyethylene (HDPE) pipes under external ground and fluid pressures up to circumferential buckling failure.; Results from six experiments conducted with ground and fluid loads applied in the radial direction are reported. The observations and recorded data included applied earth and fluid pressures, radial deflections of the pipe and images of the buckled shape of the pipe. The results showed that as fluid pressures were increased, the effective stresses acting on the pipe decreased. Buckling of the pipe occurred essentially with only fluid pressures and very little soil support, even with very high magnitudes of effective stresses applied at the external boundaries of the soil. |
