Seismic Pressure Surges in Liquid-Filled Pipelines

Abstract

Observed damage and analytic studies indicate that earthquakes may cause destructive pressure surges in liquid-filled piping. Most studies have concerned buried piping that could be assumed to move with the ground. However, pressure surges also would be expected in above-ground piping, where they would affect the displacement response and, hence, the amplitude of flexural stress in the piping. Current aseismic design practice is to simplify this effect by treating the contained liquid as incompressible mass. This paper describes a technique for computing pressure and relative displacement that incorporates elasticity of both the piping and the liquid. Seismic responses of an example pipeline are predicted. It was found that assuming the piping to be rigid produced an upper-bound estimate of pressure, but assuming the liquid to be incompressible resulted in underestimating displacement of the piping.