Nonlinear Pushover Analysis of Buried Water Pipelines under Faulting

Nonlinear Pushover Analysis of Buried Water Pipelines under Faulting

An earthquake is one of common natural disasters in Taiwan. When the earthquake occurred, underground structures such as buried water pipeline and foundation may be damaged. Because water supply is the public utility required day to day, when it cannot provide services, it must cause livelihood and health problems. It might even cause secondary disasters like fire and plague. So the damage to the pipeline caused by earthquake cannot be ignored. When continuous buried water pipeline is subjected to fault movement, damage is inevitable and water supply may be affected. In order to investigate the local buckling behavior of buried water pipelines under faulting, a sophisticated finite element method may be adopted and the pipeline is simulated by using the shell element. However, in practice, numerical analysis of buried pipelines under faulting with shell element is too complicated and time consuming for engineers. Hence, a method for nonlinear pushover analysis of buried water pipelines under faulting is proposed in this study. Nonlinear moment and axial plastic hinges are developed for the pipelines. Described in terms of plastic hinges, the nonlinear behavior of the pipelines can be simply simulated by using beam elements. In addition, restoring force provided by the surrounding soil is simulated by nonlinear link. Given angle of faulting relative to the pipeline, nonlinear pushover analysis can be conducted. From the result of the analysis, the failure mode of the pipeline and the corresponding allowable faulting movement can be achieved. This information is useful for the design of buried pipelines in seismically active areas.