An equation for estimating the maximum normal strain of buried steel pipes in bend area under propagating waves in sands
نویسندگان
1 School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran, P.O. Box 16765-163, Iran
2 Department of Civil Engineering, East Tehran Branch, Islamic Azad University, Tehran, Iran
3 The Centre of Excellence for Fundamental Studies in Structural Engineering, Iran University of Science and Technology, Narmak, Tehran, P.O. Box:16765-163, Iran
4 Department of Civil Engineering, Parand Branch, Islamic Azad University, Parand, Iran
5 Department of Civil Engineering, East Tehran Branch, Islamic Azad University, Tehran, Iran
doi
10.24200/sci.2021.55694.4356چکیده
The possible vulnerability of pipelines under propagating waves especially at bend area emphasizes the need of studying in this context. In the presented studies in this field the beam and beam-shell hybrid models were usually used but in this study a continuum model is examined. For this purpose, the bent pipe is modeled by shell elements and suitable boundary conditions are considered to simulate the infinite length of the pipe away from the bend. The soil around the pipe is modeled by 3D elements obeying the Mohr-Coulomb rule of behavior. Also, equivalent boundary conditions are used at the boundaries of the soil domain where it is truncated. By varying the properties of the pipe-soil model, it is investigated under seven different ground motions and the maximum axial strain is calculated at the bend area. Effects of different parameters including incidence angle of seismic waves, bend angle, pipe diameter to wall thickness ratio, and physical properties of soil are investigated. Using the results of analysis and regression, an equation is proposed for estimating the maximum normal strain of buried pipes at the bend area with good accuracy.
