Yunas, Dimas Alif (2015) Analisis Resiko Keruntuhan Jacket Pasca Subsidence Akibat Modifikasi Ketinggian Deck. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Umumnya diperairan Indonesia saat ini banyak platform yang sudah termasuk dalam
struktur tua. Dengan demikian perlu dilakukan risk assessment, terlebih jika platform
tersebut telah mengalami subsidence sehingga kemudian dilakukan penaikan dek
seperti platform L-COM milik PT.PHE-ONWJ. Analisis keruntuhan struktur
bertujuan untuk mengetahui kegagalan member apakah termasuk dalam sistem seri
ataupun pararel. Analisis dilakukan dengan bantuan software pemodelan elemen
hingga. Metode pushover digunakan untuk menganalisis kekuatan struktur untuk
mendapatkan nilai reserve strength ratio (RSR) dan system redundancy (SR). Dari
hasil analisa diperoleh nilai RSR terkecil adalah 5.65 pada arah pembebanan 0
derajat. Sedangkan nilai SR terkecil adalah 1.071 pada arah pembebanan 90 derajat.
Peluang kegagalan member (PoF) dilakukan dengan metode simulasi monte carlo
dengan 100.000 kali simulasi. Dari hasil simulasi diperoleh PoF sistem terkcil adalah
2.15 x 10-8 pada arah pembebanan 90 derajat. Berdasarkan matriks resiko ISO 2000,
PoF sistem struktur secara kualitatif tidak menyebabkan kerusakan yang signifikan
terhadap struktur jacket (negligible). Untuk kategori keamanan personil termasuk
dalam kategori E, untuk kategori lingkungan termasuk dalam kateogri D (major
effect), dan untuk kategori bisnis termasuk dalam kategori D (major damage).
Dengan demikian berdasarkan matriks resiko, struktur L-COM masuk dalam ALARP
(As low As Reasonably Practicable).
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Issues regard to continued usage of aging jacket platforms affecting the aged
fixed jacket platforms owned by PT. PHE-ONWJ in Indonesian waters was
studied. The jacket structure was experienced subsidence and then to remains the
operation deck-raising with hydraulic jack-up method is used. Therefore risk
assessment is necessary to be performed. Collapse analysis is used to determine
types of member failure, either in series or parallel system. This analysis was
performed by finite element software. Pushover methods was used to check the
structural strength and to obtain value of reserve strength ratio (RSR) and system
redundancy (SR). The result of analysis is found the minimum RSR is 5.65 for 0
degrees loading direction. Whereas the minimum SR is 1.071 for 90 degrees
loading direction. Probability of member failure (PoF) was performed with monte
carlo simulation method with 100.000 iterations. From the result of simulations is
obtained the smallest value of PoF system 2.15 x 10-8. Qualitatively PoF of
structural system is not significant to structural damage. Consequence of failure
(CoF) category of safety is included in category E (negligible), for CoF category
of environmental is included in category D (major effect), and CoF category of
business is included in category D (major damage). The conlusion based on risk
matrix, L-COM platform is included in ALARP (As Low As Reasonably
Practicable).
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSKe 363.102 Yun a |
| Uncontrolled Keywords: | risk assessment, subsidence, pushover, Reserve Strength Ratio, System Redundancy, monte carlo. |
| Subjects: | H Social Sciences > HD Industries. Land use. Labor > HD61 Risk Management T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures |
| Divisions: | Faculty of Marine Technology (MARTECH) > Marine Engineering > 36202-(S1) Undergraduate Thesis |
| Depositing User: | Mr. Tondo Indra Nyata |
| Date Deposited: | 19 Jun 2017 01:38 |
| Last Modified: | 24 Aug 2018 07:52 |
| URI: | http://repository.its.ac.id/id/eprint/41724 |
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