Seismic response analysis and damage assessment of urban water supply networks considering influences of crossing pipelines

Based on a buried water supply network in Beijing, the two-dimensional finite element models for the network are developed in this study. The influences of the critical parameters, such as the pipe diameter, joint type, site condition, intensity level of ground motion and incident angle of seismic wave, on the axial and bending deformations of pipe joints are systematically investigated, and the seismic damage status of the water supply network under different intensity levels of earthquakes is evaluated. Moreover, the criteria for damage assessment of the pipelines based on joint deformation are developed through the statistical analysis of the test results of the worldwide pipeline joints. These criteria are subsequently used for the seismic damage assessment of different types of pipeline joints. A seismic damage database of typical pipeline joints buried in different engineering sites is established. Finally, according to the pipeline properties, engineering site conditions and seismic damage database of typical pipeline joints, the seismic damage distribution maps of water supply networks are developed using the GIS. It is found that the peak deformations of the joints at the pipeline cross junctions are about 1.5 to 2.0 times those of the joints in a straight pipeline under the same intensity of earthquake ground motions. Besides, sudden changes of the peak seismic deformations occur at the push-on joints adjacent to the flange joints. The pipeline network suffers much more severe seismic damage under the considered maximum earthquake than under the design level of earthquake. The seismic damage mainly concentrates in the site class Ⅳ and the cross junction of the pipelines.