COLLAPSE OF LARGE WATER SUPPLY PIPELINES DUE TO INTERACTION BETWEEN LONGITUDINAL AND CIRCUMFERENTIAL RESPONSE

Abstract

Two large water supply pipelines collapsed at Osaka in 1997 and at Kyoto in 1998. Investigation on the site conditions and collapsed structures of cast iron pipes in both cases suggested that the reaction forces against the earth pressures acting along the longitudinal axes of the pipelines concentrated onto particular supporting points of the pipelines. Centrifuge model tests and FE elastic analysis revealed that the longitudinal deformation of the pipelines increased the circumferential deformation of the pipelines at the supporting points, and this interaction between the longitudinal and circumferential response was the critical factor to cause the collapse of the pipelines.