AINNILLAH, SHAILLA (2017) ANALISA ULTIMATE STRENGTH STRUKTUR JACKET PLATFORM BERBASIS KEANDALAN PASCA SUBSIDENCE. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Efek penurunan tanah pada offshore structure akan sangat berbahaya terutama pada ekofisik jika penurunan tanah terjadi 6 meter. Dari dampak negatif tersebut maka dilakukan perhitungan besar nya penurunan tanah yang dapat digunakan sebagai basis dalam mendesain bangunan lepas pantai sebagai proteksi yang penting. Oleh karena itu, perlu dilakukan analisa dampak subsidence yang berakibat penurunan kekuatan struktur secara keseluruhan yang sudah berbeda dari rancangan awal. Pada tugas akhir ini dilakukan analisa keandalan pada jacket well and production tetrapod platform KLB PHE ONWJ dalam kondisi ultimate dengan variasi kedalaman subsidence. Analisa ultimate dilakukan dengan meningkatkan beban lingkungan kondisi badai secara bertahap hingga struktur mengalami keruntuhan karena terbentuknya member-member pada keadaan plastis. Member dengan plastisitas 100% akan digunakan dalam analisa keandalan, dimana peluang kegagalannya diperoleh dengan simulasi Monte Carlo yang menggunakan Random Number Generator (RNG). Sedangkan keandalan sistem diperoleh dengan metode Reliability Block Diagram (RBD). Berdasarkan analisa kekuatan struktur diperoleh kedalaman subsidence maksimum agar tetap memenuhi API RP 2A WSD adalah kedalaman 5 meter dengan unity check of member terbesar mencapai 0,86. Pada analisa keruntuhan diperoleh hasil RSR terkecil 2,141 pada kondisi subsidence 6 meter akibat arah pembebanan 00. Analisa keandalan sistem dilakukan untuk kondisi non subsidence hingga kondisi subsidence 6 meter dengan keandalan terkecil mencapai 0,454646 dan PoF terbesar 0,545354.
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The effect of decreasing soil on offshore structure will be very dangerous, especially on eco-physics if subsidence occurs 6 meters. The negative impact of the calculation of its large land subsidence can be used as a basis in the design of offshore building as an important protection. Therefore, subsidence analysis that a commodates subsidence, collapse analysis need to be done, because the structure is different from initial design. Reliability analysis in this final project will be done on KLB PHE ONWJ jacket well and production tetrapod platform in the ultimate conditions with subsidence depth variation. Ultimate analysis is done by increasing gradually the environmental storm condition until structure collapse due to the defotmation of the members in to plastic condition. Member with 100% plasticity is used in the system reliability analysis, where the probability of failure are obtained using Monte Carlo simulation. Whereas, the reliability of the system obtained by the Reliability Block Diagram (RBD) method. Based on structural strength analysis, the result of maximum subsidence depth in order to comply with API RP 2A WSD standard is 5 meters depth of subsidence, with the largest unity check of member reaches 0,86. On the collapse analysis, the result of smallest RSR is 2,141 with the subsidence condition 6 meters due to loading direction 00. The system reliability analysis was done for non-subsidence condition until 6 meters subsidence with the smallest reliability reaches 0,454646 and the largest probability of failure is 0,545354.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Uncontrolled Keywords: | Monte Carlo, Reliability Block Diagram, Subsidence, Ultimate |
| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) > TA645 Structural analysis (Engineering) T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Shailla Ainnillah Agawijaya |
| Date Deposited: | 27 Jan 2017 01:57 |
| Last Modified: | 08 Mar 2019 06:31 |
| URI: | http://repository.its.ac.id/id/eprint/3614 |
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