Evaluating the Effects of Earthquake Wave Propagation on Buried Curved Pipes Using Static Analysis

Abstract

Pipelines as lifeline play a key role in water, gas, and oil delivery. One of the effective factors in the design of buried pipes is fault existence on its path. One of the other effective factors in the pipeline design is the propagation of earthquake waves along it. Wave propagation means that the different parts of the pipes are vibrating with different values of accelerations due to earthquake wave propagation. This phenomenon can cause great stress and strain in the pipes. For determining the response of the burial pipelines due to wave propagation, a specific time history analysis is necessary using an earthquake accelerogram, which is highly complicated. The present study was conducted to evaluate the effects of earthquake wave propagation on the seismic response of curved buried pipes using simple method. In this method, it is assumed that during the earthquake, the burial pipe in the soil is deformed the same as its surrounding soil. Therefore, for seismic analysis of the pipe, the displacement record is used instead of acceleration record. The results showed that the earthquake wave propagation affect the seismic performance of buried pipelines considerably. Hence, it can be claimed that a decrease in the wave velocity in the soil would result in an increase in the longitudinal component of strain in the pipeline. Moreover, it was found that the curvature angle of 30° would have the greatest effect on the seismic response of pipelines. Finally, it was demonstrated that the longitudinal component of vibration has a greater effect on pipeline design compared to other components of the vibration.