Analisa Kekuatan Ultimate Struktur Jacket dengan Pendekatan LRFD dan Berbasis Keandalan

Wijaya, Arief Santoso (2006) Analisa Kekuatan Ultimate Struktur Jacket dengan Pendekatan LRFD dan Berbasis Keandalan. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

[img]
Preview
Text
4301100006-Undergraduate Thesis.pdf - Published Version

Download (19MB) | Preview

Abstract

Analisa struktur merupakan salah satu bagian penting yang harus dilakukan dalam proses perancangan bangunan lepas pantai. Penambahan peralatan-peralatan pada struktur jacket akan dapat mempengaruhi kekuatan dari struktur itu sendiri. Untuk menghindari keruntuhan struktur yang diakibatkan penambahan peralatan, maka struktur harus dianalisa ultimate strength (push over) terlebih dahulu. Pada awal analisa design level, struktur APN-D tidak mengalami suatu kegagalan pada seluruh member. Selanjutnya dilakukan analisa push over dengan penambahan beban lingkungan (gelombang, arus) dan beban vertikal (selfweight, deck load, dan lain-lain) sebagai beban konstan. Pembebanan yang dilakukan menurut API RP 2A LRFD I 51 edition dimana pembebanan ini lebih besar dari API RP 2A WSD 21 51 edition. Dari analisa ultimate strength (push over) yang telah dilakukan maka didapat nilai RSR (Reserve Strength Ratio) dari struktur APN-D. RSR minimum 2.4 diperoleh untuk beban gelombang arab 330°,dan SR sebesar 1.2, sedang untuk harga ini masih di atas aman sesuai dengan ketetapan API RP 2A WSD 21 51 edition, yakni sebesar 1.6. Selanjutnya untuk mengetahui keandaan sistem struktur APN-D ini perlu dianalisa keandalan. Tegangan ultimate member (56 ksi - 80 ksi) disimulasikan dengan tegangan ultimate member pada saat kondisi ultimate dengan metode AFOSM. Sehingga didapat level reliability berupa Keandalan sistem sebesar 0.9999. Dari nilai RSR, SR dan level reliability struktur APN-D dalam batas aman sehingga tidak perlu mitigasi. ========================================================================================= Structural analysis is one of the most important factor that should be performed in the design process of anoffshore structure. Modification in the form of additional facilities is often carried out on existing platformthat affect the structural strength. To avoid the collaps of structure caused by facilities addition to the structure must be performed ultimate strength analysis. In the design level analysis of APN-D platform failed member was not found. After design level was performed, the next analysis should be performed is push over analysis by setting up enviromental load as an incremental load and payload was set as a constant load. Loading by API RP 2A LRFD larger than API RP 2A WSD. Ultimate strength analysis needs to be carried out to determine the structural reserve strength ratio of APN-D platform. Results of this analysis show the minimum RSR (Reserve Strength Ratio) value of the APN-D structure is 2.4 caused by wave load directions of 330°. This value eventually is higher than the minimum requirement of API RP 2A WSD, which is 1.6. The Ultimate Strength Reliability Analysis needs to be performed to assure the system reliability of APN-D structure, by using Advanced First Second Order Moment (AFOSM) method. The Ultimate Stress from material (56- 80 ksi) simulated with ultimate stress material in Ultimate Limit State condition. The structural system reliability of APN-D is 0.9999. The value of Reserve Strength Ratio, System Redudancy and system reliability of APN-D structure are found to be in the safe range, is so it doesn't require any mitigation.

Item Type: Thesis (Undergraduate)
Additional Information: RSKe 627.98 Wij a
Uncontrolled Keywords: increment, assessment, design level, Push Over, RSR, stress, tegangan
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 > Ocean Engineering > (S1) Undergraduate Theses
Depositing User: Eny Widiastuti -
Date Deposited: 13 Jul 2018 07:30
Last Modified: 13 Jul 2018 07:30
URI: http://repository.its.ac.id/id/eprint/52145

Actions (login required)

View Item View Item