Plastic deformation behaviour of polyethylene pipes under displacement : polyethylene pipeline systems survive the great Hanshin-Awaji earthquake without failures

Polyethylene pipe satisfies the displacement absorption requirement of 5 cm, which is specified in the seismic design guidelines. Displacement causing plastic deformation has been applied to polyethylene pipes and the molecular structure of plastic deformed parts was studied to evaluate the short term and long term strength of polyethylene pipes. The result shows that polyethylene pipes have no problem in practical use. PRCPA/1529.