Analisis On Bottom Stability Pada Jacket Platform yang Mengalami Kemiringan Pasca Settlement

Ramadhan, Reynaldi Rovi (2018) Analisis On Bottom Stability Pada Jacket Platform yang Mengalami Kemiringan Pasca Settlement. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Permasalahan operasi pada struktur jacket platform apabila terjadi ialah kemiringan struktur. Daya dukung tanah yang kurang dapat menyebabkan struktur mengalami penurunan (settlement). Akibat kemiringan struktur, segala kegiatan operasional pada platform tersebut dapat diberhentikan sementara. Pada tugas akhir ini dilakukan analisis on bottom stability struktur platform dalam kondisi miring. Tujuan dari analisa on bottom stability ialah memperoleh nilai safety factor dari daya dukung tanah (bearing capacity), momen guling (overturning moment), dan sliding stability pada pondasi akibat beban lingkungan dan vertikal terhdap nilai safety factor yang diijinkan (API RP-2A WSD). Metoda yang digunakan dalam analisis ini ialah permodelan dengan Finite Element Method (FEM) dengan menggunakan software SACS ver. 5.6. Struktur dianalisa dalam kondisi kemiringan sampai dengan 3 derajat dan ketinggian gelombang sampai dengan 12 ft. Pada kemiringan 3 derajat diperoleh hasil akhir nilai safety factor terhadap stabilitas on bottom stability struktur. Untuk struktur dengan 3 mudmat nilai safery factor terhadap bearing capacity : 13.223, sliding : 2.10, dan overturning : 1.95. Sedangkan untuk struktur dengan full mudmat nilai safety factor terhadap bearing capacity : 13.333, sliding : 2.51, dan overturning: 2.02. Untuk struktur tanpa pondasi mudmat nilai safety factor bearing capacity : 12.705, sliding : 0.57, dan overturning : 1.54. Pada kemiringan 3 derajat ada parameter yang tidak memenuhi kriteria analisa on bottom stability API RP-2A WSD yaitu sliding stability (SF : 0.57) dan overturning stability (SF : 1.54). Sedangkan untuk analisa bearing capacity telah memenuhi kriteria API RP-2A WSD. ========== The most problematical operation of offshore fixed structure is tilting condition of the structure. A poor bearing capacity of the foundation can cause settlement of the structure. Due to the tilt of the structure, all operational activities on the platform could be suspended. The main purpose of the on-bottom stability analysis is to obtain factor of safety from bearing capacity, overturning moments, and sliding stability of the foundation due to environmental and lateral loads allowed on (API RP-2A WSD). Finite Element Method (FEM) software SACS will be used to perform modeling of the structure. The result of this final project is to obtain the minimum safety factor of the structure stability from the on bottom stability analysis consists of bearing capacity, overturning moments, and sliding stability up to 3 degree tilt and 12 feet wave height. Thus, factor of safety is obtained from the on bottom analysis of 3 mudmat structure with bearing capacity factor of safety : 13.223, sliding stability factor of safety : 2.10, overturning stability factor of safety : 1.95. While for the on bottom stability analysis of full mudmat whereas bearing capacity factor of safety : 13.333, sliding stability factor of safety : 2.51, overturning stability factor of safety : 2.02. Then, for the on bottom stability analysis of structure without mudmat with bearing capacity factor of safety : 12.705, sliding stability factor of safety : 0.57, and overturning stability factor of safety : 1.54. It concludes that the structure with full mudmat fulfil all the criteria of on bottom stability analysis as from the recommendation on API RP-2A WSD due to tilt. Whereas structure without mudmat could not fulfil 2 of 3 parameters on bottom stability analysis due to sliding stability (SF : 0.57) and overturning stability (SF : 1.54).

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: Kemiringan Struktur; On Bottom Stability; Settlement; Bearing Capacity; Overturning Moment; Jacket Platform
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA347 Finite Element Method
T Technology > TA Engineering (General). Civil engineering (General) > TA645 Structural analysis (Engineering)
Divisions: Faculty of Marine Technology > Ocean Engineering > (S1) Undergraduate Theses
Depositing User: Ramadhan Reynaldi Rovi
Date Deposited: 22 Jan 2018 02:20
Last Modified: 22 Jan 2018 02:20
URI: http://repository.its.ac.id/id/eprint/49855

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