EARTHQUAKE DAMAGE FACTOR OF LARGE-DIAMETER PIPE BASED ON SIZE EFFECT OF SEISMIC RESISTANCE FOR THE TRANSVERSE DIRECTION OF WATER PIPE

Abstract

 Referring from the case where several pipes with large diameter had damaged with cracks by the earthquake in northern Osaka in 2018, it is considered that not only factors such as insufficient strength and deterioration but also that the pipes with larger diameters is more vulnerable than those with small diameters for the seismic resistance in the transverse direction, which is a so-called size effect. In this study, the more accurate calculation method using soil-and-pipe FEM model and giving inertial force without using soil spring. The influence of the diameter on the seismic response for water pipes with small to large diameters are made clarified. Furthermore, the seismic resistance was compared under various conditions with regard to the damage factor of the 900 mm diameter pipe during the last earthquake. As a result, it was found that the reduction in pipe thickness due to corrosion deterioration contributes more as a damage factor than the increase in hydraulic pressure during the earthquake.