Strength and ductility level earthquake design for Gulf of Suez oil platforms

摘要

Gulf of Suez area which characterized by a moderate seismic activity is consider as a very important area in Egypt. Nearly 75 of the national oil production is covered from this area. Seismic hazard (both probabilistic and deterministic) was carried out to study the possibility of earthquake damage in the area; a new seismic model was used taking into account the seismo-tectonic framework of the region. The hazard calculations utilized at strength and ductility level periods at the whole area of the Gulf of Suez. Fundamentally, the hazard calculations were performed at bedrock conditions, and the spectrum was estimated over the period range of 0.001-12s. At Abou Zeniama area, where many oil platforms exist, the hazard was calculated at the sea floor, at depth 4.7m and at depth 26.0m. The maximum spectral accelerations at strength level earthquakes (SLEs) are found to be 0.260 (g), 0.203 (g), and 0.156 (g) for 90.48 chance, of non-exceedance in 50years (return period 500year) at sea floor, at depth 4.7m and at depth 26m, respectively. While the ductility level earthquake (DLE) are found to be 0.30 (g), 0.23 (g), and 0.18 (g) for 95.12 chance of non-exceedance in 50years (return period 1000year) at sea floor, at depth 4.7m, and at depth 26m, respectively. The deterministic hazard calculation was estimated at 50th and 84th percentile levels for the median peak ground acceleration. The study target initiated from the importance of studying the seismic hazard, SLE, and DLE in the area which contain most of the Egyptian oil industry with many off shore platforms.