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All Journal Jurnal Teknik Sipil dan Perencanaan Collegium Studiosum Journal Journal of the Civil Engineering Forum Jurnal Pengadaan Barang dan Jasa
Zakariya, Ali
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Humanities Civil Engineering, Building, Construction & Architecture Law, Crime, Criminology & Criminal Justice Social Sciences

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The Correlation of Liquefaction Potential and Probability on Excess Pore Water Pressure in Kretek 2 Bridge Area Zakariya, Ali; Rifa'i, Ahmad; Ismanti, Sito
Journal of the Civil Engineering Forum Vol. 10 No. 1 (January 2024)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jcef.7002

Abstract

Liquefaction is soil condition associated with the drastic increase in pore water pressure of uniform sandy soil due to an enormous earthquake. Therefore, this study aimed to investigate the correlation of liquefaction potential with excess pore water pressure ratio in nine boreholes located at Kretek 2 Bridge area using empirical and numerical methods. Liquefaction potential was estimated based on a semi-empirical method simplified by Idriss and Boulanger (2008), and safety factor (SF) value of <1.0 was used to represent the existence of its potential. The result showed that liquefaction potential was dominant at depths of 1.5 to 6.0 m, with the exception of BH-9 with 16.5 m and BH-4. Furthermore, the excess pore water pressure ratio was estimated using empirical method developed by Yegian and Vitelli (1981) as well as Serafini and Perlea (2010). Numerical analysis was also conducted for comparison purposes and the process focused on using Deepsoil v7.0 to generate excess pore water pressure by considering soil conditions and dominant seismic sources in Kretek 2 Bridge area. The result showed that the ratio of excess pore water pressure was greater or equaled 0.8. Both empirical and numerical methods produced similar values for BH-1, BH-2, BH-8, and BH-9 at a depth of 1.5–3.0 m, 3–4.5 m, 3.0 m, and 16.5 m, respectively. This showed a correlation between excess pore water pressure ratio and liquefaction potential values at the same depth. However, numerical method tended to overestimate the ru value, necessitating the use of empirical method to obtain a more reliable result.
Behaviour of Axial Bearing Pile under Liquefaction Condition Based on Empirical and 3D Numerical Simulation Zakariya, Ali; Rifa’i, Ahmad; Ismanti, Sito
Jurnal Teknik Sipil dan Perencanaan Vol 25, No 1 (2023)
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jtsp.v25i1.42954

Abstract

The liquefaction phenomenon affects to bearing capacity losses of building foundations. When liquefaction occurs in loose sandy soils, the pore water pressure increases, and the effective soil stress decreases significantly. This study deals with the bored pile foundation of Kretek 2 bridge, which is located in an area with high vulnerability to liquefaction. The study aimed to estimate the axial load-bearing capacity of the foundation of Kretek 2 bridge under liquefaction conditions. This study compares the results of calculations using empirical approaches with 3D numerical simulation modeling using MIDAS GTS NX. The results of the empirical calculations show a reduction in the axial bearing capacity of the foundation under liquefaction conditions of 2.88-8.16% and 2.63-7.23% for the approach of Reese and Wright 1977 and O’Neill and Reese 1989, respectively. While using 3D numerical modeling, although there was a decrease in skin resistance, there was no significant decrease in the total bearing capacity, and it was still above the design load (3632.563456.02 kN). Based on these results, the bearing capacity of the installed Kretek 2 Bridge foundation is still capable of receiving loads during static and liquefaction states.
Percepatan Pengadaan Jembatan Gantung sebagai Infrastruktur Penghubung antar Desa melalui e-Purchasing Zakariya, Ali; Priyadi, Panji Arrie; Widhatra, Hendra
Jurnal Pengadaan Barang dan Jasa Vol. 3 No. 1 (2024): Jurnal Pengadaan Barang dan Jasa, Edisi April 2024
Publisher : Ikatan Fungsional Pengadaan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55961/jpbj.v3i1.46

Abstract

Negara Indonesia memiliki wilayah dominan berkontur pegunungan dengan sungai yang membelah mengakibatkan banyaknya akses pedesaan yang terisolir. Pembangunan infrastruktur jembatan gantung pejalan kaki dapat menjadi penghubung antar Desa sesuai dengan visi misi Presiden Republik Indonesia 2019-2024 dalam membangun daerah tertinggal, terdepan, dan terluar dalam rangka Negara Kesatuan. Pada tahun 2022, pengadaan jembatan gantung pejalan kaki di Direktorat Pembangunan Jembatan, Direktorat Jenderal Bina Marga telah menggunakan sistem e-purchasing melalui e-katalog sektoral LKPP menggantikan sistem lelang. Penggunaan e-purchasing di Kementerian Pekerjaan Umum dan Perumahan Rakyat bertujuan untuk menerapkan prinsip pengadaan dan mengakomodir kemajuan teknologi. Penerapan sistem ini juga didorong oleh Peraturan Presiden Nomor 16 Tahun 2018 beserta turunannya. Penelitian ini mengungkapkan hubungan antara perubahan sistem pengadaan terhadap durasi pengadaan. Perubahan sistem menjadi e-purchasing mengakibatkan penyederhanaan business process pengadaan jembatan gantung pejalan kaki dari semula melalui sistem lelang dan tahapan desain menjadi sistem pemilihan penyedia melalui e-katalog dengan desain telah terstandar. Penyederhanan ini memangkas durasi pengadaan dari sebelumnya lebih dari 5 (lima) bulan menjadi kurang dari 4 (empat) bulan. Selain itu, sistem e-purchasing memungkinkan keikutsertaan penyedia barang semakin banyak dengan peningkatan produktifitas mencapai 0.9 unit/hari. Dengan menurunnya durasi pengadaan maka akan berdampak pada percepatan pemerataan infrastruktur di pelosok daerah.
PERAN KOMISI PENGAWAS PERSAINGAN USAHA SEBAGAI WASIT SEKALIGUS HAKIM DALAM EKONOMI Dewi, Ratna; Timori, Helmin Porang; S, Moh. K. Aripin; Zakariya, Ali; Putri, Audrey Aulia; Taena, Markus; Ramadhanty, Andiera Eko
Collegium Studiosum Journal Vol. 7 No. 2 (2024): Collegium Studiosum Journal
Publisher : LPPM STIH Awang Long

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56301/csj.v7i2.1417

Abstract

The Business Competition Supervisory Commission (KPPU) is a state institution that has a crucial role in maintaining balance and fairness in the dynamics of the Indonesian market. As a supervisor of business competition, KPPU functions as a referee who ensures that all business actors play by the same rules. Its main task is to prevent monopolistic practices, cartels, and other unfair competition that can harm consumers and hinder economic growth. The purpose of this study is to determine the problems faced by KPPU in carrying out its duties. The research method used is normative juridical. The data analysis is by using the Qualitative method. The results of the study are that in carrying out its duties, KPPU still faces a number of challenges. One of the main challenges is the increasing complexity of business competition cases, especially along with the development of technology and globalization. In addition, KPPU also needs to continue to improve the capacity of its human resources in order to handle cases more quickly and effectively. The conclusion is that KPPU needs to continue to make various efforts, such as strengthening coordination with related institutions, increasing public awareness of the importance of healthy business competition, and developing information technology to support the supervision process. KPPU also needs to continue to conduct studies and research to understand the latest developments in market dynamics and business competition. In the increasingly developing digital era, KPPU also needs to pay attention to the development of digital technology and its impact on business competition. For example, KPPU needs to anticipate the potential for monopolies or cartels in digital platforms, and ensure that digital innovation does not hinder healthy competition. By carrying out its dual role as referee and judge effectively, KPPU can contribute significantly to realizing a fair, efficient, and competitive Indonesian economy.
Co-Authors Ismanti, Sito Priyadi, Panji Arrie Putri, Audrey Aulia Ramadhanty, Andiera Eko Ratna Dewi Rifa’I, Ahmad Rosyadi, Sasri S, Moh. K. Aripin Taena, Markus Timori, Helmin Porang Veithzal Rivai Zainal Widhatra, Hendra Yudhono, Giri