Analisis Resiko Keruntuhan Jacket Pasca Subsidence Akibat Modifikasi Ketinggian Deck

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). =============================================================================================== 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--Models
Divisions: Faculty of Marine Technology > Marine Engineering > (S1) Undergraduate Theses
Depositing User: Mr. Tondo Indra Nyata
Date Deposited: 19 Jun 2017 01:38
Last Modified: 19 Jun 2017 01:38
URI: http://repository.its.ac.id/id/eprint/41724

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