Physical modelling of the seismic response of gas pipelines in laterally in homogeneous soil

This paper reports on results from a series of 1-g, reduced-scale, shake table tests of a 216mlong portion of an onshore steel gas transmission pipeline embedded in horizontally layered soil. A set of first-order set of dynamic similitude laws was employed to scale system parameters appropriately. Two sands of different mean grain diameter and bulk density were used to assemble a compound symmetrical test soil consisting of three uniform blocks in a dense-loose-dense configuration. The sandpipe interface friction coefficients were measured at 0.23 and 0.27. Modulated harmonic and recorded ground motions were applied as table excitation. To monitor the detailed longitudinal strain profiles in the model pipe, bare Fiber Bragg Grating cables were deployed. In most cases, the pipe response was predominantly axial while bending became significant at stronger excitations. levels. Strain distributions displayed clear peaks at or near the block interfaces, in accord with numerical predictions, with magnitudes increasing at resonant frequencies and with excitation level. By extension to full-scale, peak axial strain amounted to approximately 10-3, a demand half the yield strain, but not negligible given the low in-situ soil stiffness contrast and soil-pipe friction