Longitudinal response of buried pipeline under non-uniform seismic excitation from multi-point shaking table tests

Abstract

The spatial variability of ground motion has a significant influence on the seismic response of long infrastructure and is considered the primary cause of pipeline damage during earthquakes. In this study, a series of three-dimensional shaking table tests were carried out to investigate the influence of non-uniform seismic excitation on the pipeline response using a scaled pipeline model installed in sand. The pipeline-soil model was enclosed in a suspension continuum soil box situated on three shaking tables that can induce uniform and non-uniform seismic excitations. Accelerometers were distributed along the soil profile, and strain gauges and accelerometers were attached to the pipeline to monitor the dynamic response of the pipeline-soil system during the shaking. The pipeline-soil model was subjected to a series of uniform and non-uniform excitations with gradually increasing intensity. The testing results demonstrated that the pipeline experienced tensile and compressive strains due to the longitudinal seismic excitation because the phase and waveform of the seismic waves were almost the same at the strain measuring points around the pipeline profile. The acceleration response of the pipeline under non-uniform seismic excitation was larger than that of the surrounding soil. The pipeline strain response under non-uniform seismic excitation was approximately twice that under uniform seismic excitation. The soil-pipeline interaction exhibited complex behavior; sliding may occur with the increase of loading intensity, and more likely to occur under non-uniform seismic excitation. These results indicate that the dynamic response of the pipeline-soil system is sensitive to non-uniform ground motion, which should be properly considered in the seismic design of pipeline.