Seismic Simulation Testing of PVC-U Pipe and Proposed Design Prediction Tool for Joint Performance

Abstract

Prior to the 2010–2011 Christchurch earthquake sequence in New Zealand, buried pipes were thought to be tested with respect to all expected significant loadings as specified by material standards, such as AS/NZS 1477 for PVC pipes. However, the amount of damage to pipe joints observed in the field led the authors to believe that adding an axial joint load to the tests already mandated would greatly enhance the seismic design of pipes. For this purpose, an experimental investigation was completed on diameter nominal (DN)225 mm PVC-U pipe joints to ascertain the serviceability and ultimate limit state allowable loads when a pipe joint is subjected to axial seismic-simulated actions. The experimental results were able to replicate reported pipe earthquake damage by incorporating forces simulating peak ground accelerations in both the horizontal and vertical directions in the testing and by subsequently deriving relevant formulae. This research suggests that the existing compliance pipe standards can be easily modified to better replicate the observed seismic pipe damage, and the derived formulae could be used to improve decision support system models used by buried infrastructure asset owners to provide better postdisaster functionality information on their pipelines. The formulae presented herein are first-order checks and do not account for ground strains, ground displacements, or tensile actions. However, the proposed approach allows simplistic multiscenario comparative analysis to be done with relative ease.