Analisis Stabilitas Dasar Dan Penurunan Tanah Pada Struktur Pondasi Skid Frame Subsea Valve Studi Kasus Perairan Indramayu

Fitri, Charlizze Coral Nabila (2026) Analisis Stabilitas Dasar Dan Penurunan Tanah Pada Struktur Pondasi Skid Frame Subsea Valve Studi Kasus Perairan Indramayu. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Struktur subsea yang ditempatkan langsung di dasar laut tanpa sistem pondasi tiang menghadapi tantangan stabilitas akibat beban lingkungan berupa gelombang dan arus, serta potensi penurunan tanah akibat beban permanen struktur. Penelitian ini membahas analisis stabilitas dasar dan penurunan tanah pada struktur pondasi skid frame subsea valve (SSV) yang berlokasi di perairan Indramayu, Laut Jawa, sebagai bagian dari pengembangan fasilitas Ardjuna Marine Terminal. Pemodelan struktur dilakukan menggunakan perangkat lunak SACS 2025 dan divalidasi terhadap hasil material take off, dengan diperoleh selisih sebesar 1,87%. Analisis stabilitas dasar mengacu pada API RP 2A-WSD, meliputi pemeriksaan daya dukung tanah, stabilitas geser, dan stabilitas guling pada kondisi gelombang 1 tahun dan 100 tahun dari delapan arah pembebanan. Hasil analisis menunjukkan nilai faktor keamanan minimum sebesar 13,02 untuk daya dukung tanah, 14,30 untuk stabilitas geser, dan 10,68 untuk stabilitas guling, seluruhnya melampaui kriteria minimum API RP 2A-WSD. Perhitungan penurunan tanah dilakukan menggunakan tiga metode, yaitu API RP 2A-WSD, Janbu, dan Terzaghi, dengan hasil berturut-turut sebesar 5,70 mm, 6,29 mm, dan 6,98 mm, menunjukkan konsistensi antar metode dan nilai penurunan yang tergolong kecil. Evaluasi kekuatan struktur melalui analisis in-place pada SACS menghasilkan unity check maksimum sebesar 0,117 pada elemen struktur, sedangkan pemeriksaan pelat mudmat dan skirt plate masing-masing menghasilkan unity check sebesar 0,259 dan 0,028. Berdasarkan hasil tersebut, dapat disimpulkan bahwa struktur skid frame subsea valve pada kondisi eksisting memiliki kestabilan dan kekuatan yang memadai untuk menahan beban lingkungan dan beban operasional selama masa layanannya.
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Subsea structures placed directly on the seabed (on-bottom) without a piled foundation system face stability challenges due to environmental loads from waves and currents, as well as the potential for settlement caused by the permanent loads of the structure. This research addresses the on-bottom stability and settlement analysis of the foundation structure of a subsea valve skid frame (SSV) located in Indramayu waters, Java Sea, as part of the Ardjuna Marine Terminal facility development. The structure was modeled using SACS 2025 software and validated against material take-off results, yielding a discrepancy of 1.87%. The on-bottom stability analysis was conducted with reference to API RP 2A-WSD, covering bearing capacity, sliding stability, and overturning stability checks under 1-year and 100-year wave conditions from eight loading directions. The results show minimum safety factors of 13.02 for bearing capacity, 14.30 for sliding, and 10.68 for overturning, all of which exceed the minimum criteria required by API RP 2A-WSD. Settlement calculations were performed using three methods, namely API RP 2A-WSD, Janbu, and Terzaghi, yielding values of 5.70 mm, 6.29 mm, and 6.98 mm respectively, indicating consistency among the methods and a relatively small settlement magnitude. Structural strength evaluation through in-place analysis in SACS produced a maximum unity check of 0.117 on the structural members, while the mudmat plate and skirt plate checks resulted in unity checks of 0.259 and 0.028, respectively. Based on these results, it can be concluded that the subsea valve skid frame structure in its existing condition possesses adequate stability and strength to withstand environmental and operational loads throughout its service life.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	stabilitas dasar, penurunan tanah, pondasi dangkal;on-bottom stability, settlement, shallow foundation
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA660.F7 Structural frames. T Technology > TA Engineering (General). Civil engineering (General) > TA681 Concrete construction T Technology > TA Engineering (General). Civil engineering (General) > TA749 Soil stabilization T Technology > TA Engineering (General). Civil engineering (General) > TA775 Foundations.
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Charlizze Coral Nabila Fitri
Date Deposited:	23 Jul 2026 01:33
Last Modified:	23 Jul 2026 01:33
URI:	http://repository.its.ac.id/id/eprint/136242

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