Seismic and dynamic response characteristics of flax fiber-reinforced epoxy pipes

Abstract

Dynamic and seismic response characteristics of free-spanning above-ground flax fibre-reinforced epoxy (FFRE) pipes with various diameters of 38, 60, 100, 160, and 205 mm and different fabric layers of 2, 3, and 4 (thickness of 3.4 mm–6.65 mm), and a free span of 3870 mm were investigated experimentally and numerically. The FFRE pipes were subjected to harmonic ground motions with peak ground acceleration of 0.1g, 0.2g, and 0.3g, vibration frequency of 2, 4, and 6 HZ, and a duration of 40 s, and a record from the 2011 Christchurch earthquake when the pipe was empty, half-filled or completely-filled with water to establish the effect of peak ground acceleration, vibration frequency, pipe water content, diameter and thickness on pipe displacement, acceleration, strain, and internal pressure. FFRE pipes underwent larger displacements and strains and higher transverse accelerations when the pipe was completely-filled, while the pipe underwent higher vertical acceleration and higher internal pressure when the pipe was half-filled. The pipe strain increased by up to 719% by increasing the peak ground acceleration from 0.1g to 0.3g, up to 452% by increasing the vibration frequency from 2 to 6 Hz, and up to 1358% by increasing the pipe water content from empty to completely-filled. FFRE pipes remained below their material ultimate limits, and no service or structural failure in the form of seepage or excessive deformation was detected in the pipe body, indicating great potential for using FFRE pipes as an alternative option to conventional pipes at seismic zones.