Asrul Mariadi, Asrul Mariadi (2023) Studi Alternatif Struktur Abutment dan Oprit Jembatan Diatas Tanah Lunak Di Area Food Estate Belanti, Kabupaten Pulang Pisau, Kalimantan Tengah Studi Kasus: Jembatan Muara Tahai (Sta. 0+100). Masters thesis, Institut Teknologi Sepuluh Nopember.
![[thumbnail of 6012201081-Master_Thesis.pdf]](http://repository.its.ac.id/style/images/fileicons/text.png) |
Text
6012201081-Master_Thesis.pdf - Accepted Version Restricted to Repository staff only until 1 April 2025. Download (7MB) | Request a copy |
Abstract
Salah satu program Proyek Strategis Nasional (PSN) yaitu peningkatan jembatan yang berada di jalan akses menuju kawasan tersebut. Jembatan Muara Tahai yang terletak di Sta. 0+100 pada Ruas Simpang Tiga (Sp.3) Janas – STI merupakan salah satu jembatan yang akan ditingkatkan. Panjang jembatan adalah 50 m, berada diatas sungai DIR Basarang yang terletak di Desa Tarung Manuah. Tinggi ruang bebas jembatan dari muka air banjir tertinggi sekitar 2,47 meter. Kondisi eksisting pangkal jembatan (abutmen) yang terletak diawal dan akhir jembatan tidak memiliki timbunan tanah (oprit) dibelakangnya; jadi ketinggian dari abutmen rata dengan muka tanah asli. Jembatan ini hanya dapat dilalui satu arah untuk kendaraan roda empat. Lebar sungai eksisting 32.0 m dan muka air banjir tertinggi dari dasar sungai sebesar 2,28 m.
Abutment dari jembatan Muara Tahai yang akan ditingkatkan tersebut terletak diatas tanah lunak jenis lempung kelanauan yang berwarna abu-abu kecoklatan; ketebalan lapisan tanah tersebut sekitar 25 meter dengan nilai N-SPT berkisar 0-13. Pada kedalaman lebih dari 25 m, jenis tanahnya didominasi oleh pasir halus berwarna abu-abu dengan konsistensi sangat padat dengan nilai N-SPT nya lebih besar 50. Perencanaan abutment eksisting memiliki lebar 3.0 m dan tinggi 2.50 m (termasuk tebal pile cap 1.0 m) dengan ditopang oleh pondasi tiang diameter 50 cm dan panjang 28 m sebanyak 8 buah. Sedangkan oprit direncanakan tinggi 0.95 meter, panjang 9.0 meter, dan lebar 10 m; oprit diperkuat dengan 400 buah cerucuk yang masing-masing memiliki ukuran panjang 4.0 m dan diameter 0.1 m.
Perencanaan eksisting abutment tersebut akan dianalisis dan juga akan didesain ulang dengan menggunakan floating foundation. Analisis perencanaan didasarkan pada beban yang harus dipikul oleh abutment yaitu beban akibat konstruksi jembatan dan tanah yang ada dibelakang abutment. Jembatan yang direncanakan tersebut harus stabil dan tidak turun akibat pemampatan tanah dasar dibawah abutment.
Hasil analisis menunjukkan bahwa tebal pile cap cukup hanya 0.70 m saja sehingga tinggi total abutment 2.2 m; lebar abutment tetap 3.0 meter. Jumlah pondasi tiang yang diperlukan tetap sebanyak 8 buah dengan diameter 50 cm dan panjang 20 m (lebih pendek 8.0 m dari desain eksisting). Apabila digunakan floating foundation menggunakan Floaton yang memiliki ukuran lebar 0.5 m, panjang 0.5 m, tinggi 0.4, dan berat 60 kg, maka diperlukan box sebesar 11.0 m x 3.2 m x 1.5 m sebagai wadah dari 528 buah floaton yang diperlukan.
Perkuatan cerucuk dibawah timbunan oprit, ternyata membutuhkan tambahan sebanyak 44 buah cerucuk untuk meningkatkan perlawanan geser terhadap kelongsoran akibat adanya beban gandar; total cerucuk menjadi 444 buah. Apabila dipakai Geotextile sebagai perkuatan untuk menerima beban gandar pada oprit, maka diperlukan 2 lembar geotextile dengan kuat tarik 150 kN/m yang dipasang dengan jarak 0.3 m sebagai pengganti dari 44 buah cerucuk.
================================================================================================================================
The improvement of the bridge on the area's access road is one of the National Strategic Project (PSN) programs. One of the bridges that will be improved is the Muara Tahai Bridge, which is located at Sta. 0+100 on the STI Simpang Tiga (Sp.3) Section Janas - STI. The bridge spans the DIR Basarang river in Tarung Manuah Village with 50 m long. The free space height of the bridge from the highest flood water level is approximately 2.47 meters. Because the bridge abutments at the beginning and end of the bridge do not have piles of land (oprit) behind them, the height of the abutment is level with the original ground level. Four-wheeled vehicles can only pass through this bridge in one direction. The existing river is 32.0 m wide, with a maximum flood water level of 2.28 m from the river bed.
The abutment in the Muara Tahai bridge, which will be upgraded, is situated on the soft soil of the silty clay type, which is gray to brown in color; the soil layer thickness is approximately 25 meters, with N-SPT values ranging from 0 to 13. The soil type at depths greater than 25 m is dominated by fine gray sand with a very dense consistency and an N-SPT value greater than 50. The existing abutment plan is 3.0 m wide and 2.50 m tall (including a 1.0 m thick pile cap). As many as 8 pieces are supported by a pile foundation with a diameter of 50 cm and a length of 28 m. While the oprit is expected to be 0.95 meters high, 9.0 meters long, and 10 meters wide, it is reinforced with 400 cones, each of which is 4.0 meters long and 0.1 meters in diameter.
The existing abutment plan would be analyzed and redesigned to make use of a floating foundation. The planning analysis was based on the load that the abutment must bear, specifically the load caused by the bridge construction and the soil behind the abutment. The planned bridge must be stable and not sink due to subgrade compression beneath the abutments.
The analysis results showed that the thickness of the pile cap was only 0.70 m, resulting in a total height of 2.2 m and an abutment width of 3.0 meters. The required number of pile foundations was still eight pieces of 50 cm diameter and 20 m length (8.0 m shorter than the existing design). If a floating foundation with a width of 0.5 m, length of 0.5 m, height of 0.4, and weight of 60 kg was used, then a box 11.0 m x 3.2 m x 1.5 m was required as a container for the 528 pieces of floaton required.
Reinforcement of the piles under the oprit piles revealed that an additional 44 pieces of piles were required to increase shear resistance against sliding due to axle load; the total number of niches was 444. If geotextile was used as reinforcement to receive axle loads on the oprit, then two sheets of geotextile with a tensile strength of 150 kN/m must be installed at a distance of 0.3 m to replace 44 pieces of cones.
Keywords: abutment, compression, floating foundation, floaton, geotextile, oprit, pile, soft soil
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | abutment, cerucuk, floating foundation, floaton, geotextile, oprit, pemampatan, tanah lunak === abutment, compression, floating foundation, floaton, geotextile, oprit, pile, soft soil |
| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) T Technology > TG Bridge engineering |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis |
| Depositing User: | ASRUL MARIADI |
| Date Deposited: | 13 Feb 2023 03:36 |
| Last Modified: | 13 Feb 2023 03:36 |
| URI: | http://repository.its.ac.id/id/eprint/96996 |
Actions (login required)
 |
View Item |