Document Type : Original Article
Authors
1
Associate Professor, Department of Civil Engineering, Faculty of Engineering, Azarbaijan Shahid Madani Universiy, Tabriz, Iran.
2
Assistant Professor, Department of civil Engineering, Faculty of Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran
3
Graduated MsC Student in Civil Engineering-Structure, Department of Civil Engineering, Faculty of Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran.
10.22065/jsce.2024.425356.3275
Abstract
In recent years, the use of offshore pipelines in the Persian Gulf has increased greatly. With the increase in the use of offshore pipes, the need to check the safety and the possibility of damage of these pipes during an earthquake has increased. In this research, numerical modeling of non-buried offshore gas pipelines using SAP2000 V.14 software is considered and the effect of seismic wave propagation and responses of offshore pipelines with free and fixed end conditions on different soil textures. It has been discussed and investigated in two ways lying on the sea bed and open mouth. Seismic reliability analysis of the pipeline using OpenSees software to find the reliability index (β) and the annual failure probability of the marine pipeline based on the FORM, SORM and FOSM reliability analysis methods for different seismic limit states respectively. Design level earthquake (DEQ), operational level earthquake (SEQ), maximum level earthquake (MEQ) and maximum probable earthquake (MPE) have been conducted and investigated. The results showed that in the case of free opening due to the free opening of the pipe with a length of 80 meters, the displacement caused by the seismic movements of the earth is maximum. The maximum seismic displacements of the pipeline in the state of open mouth are about 4 times compared to the state of the pipeline lying on the sea bed. In terms of the design of a marine pipeline with a free opening with a fixed end state, it is reliable in terms of operation when the annual probability of marine pipeline failure related to service conditions is less than or equal to 0.01 and the seismic reliability index β is greater or be equal to 2.
The findings can be instrumental in improving the safety and reliability of offshore pipelines.
Keywords
Main Subjects
)