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All Journal Rekayasa Sipil Wahana Teknik Sipil: Jurnal Pengembangan Teknik Sipil Teras Jurnal Makara Journal of Technology Indonesian Geotechnical Journal
Prakoso, Widjojo Adi
Universitas Indonesia
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Earth & Planetary Sciences Electrical & Electronics Engineering Engineering Environmental Science Materials Science & Nanotechnology Mechanical Engineering Transportation

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Studi Numerikal Grup Fondasi Elevated Pile Cap Pada Tanah Pasir Fathia Handayani Kamal; Widjojo Adi Prakoso; Mulia Orientilize
TERAS JURNAL Vol 12, No 1 (2022): Volume 12 Nomor 1, Maret 2022
Publisher : UNIVERSITAS MALIKUSSALEH

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/tj.v12i1.682

Abstract

Abstrak Elevated Pile Cap (EPC) merupakan fondasi tertanam sebagian di dalam tanah yang rentan terhadap beban gempa karena momen fleksural yang terjadi lebih besar daripada jenis fondasi yang tertanam sepenuhnya. Studi numerikal dengan metode BNWF menggunakan aplikasi OpenSees berbasis eksperimen yang dilakukan peneliti lain dilakukan untuk mempelajari perilaku non-linear fondasi di tanah pasir. Fondasi berkonfigurasi tunggal, 2x2, dan 2x3 dimodelkan dan divalidasikan terhadap penelitian tersebut. Variasi nilai densitas pasir dan pemberian nilai p-multiplier yang berbeda diperhitungkan per baris fondasi grup. Analisis pushover monotonik dilakukan untuk mengetahui perilaku ineastik fondasi. Semua model membentuk sendi plastis pada sambungan dan di bawah tanah pada tiang leading row. Perbandingan respons individu tiap tiang dengan respons rata-rata fondasi per tiang digunakan untuk mengetahui distribusi gaya pada fondasi yang dipengaruhi oleh nilai p-multiplier. Kuat geser tanah divariasikan untuk mengetahui keelastisitasan tanah saat pembebanan di titik tertentu, di mana semakin padat tanah maka semakin cepat fase plastis tercapai. Secara keseluruhan, variasi kepadatan tanah dan nilai p-multiplier mempengaruhi perilaku inelastis fondasi. Kata kunci: EPC, fondasi grup, sendi plastis, p-multiplier, analisis pushover                                                Abstract Elevated Pile Cap (EPC), a partially-embedded foundation, is vulnerable under seismic loadings since it suffers more flexural moment than average foundations. A BNWF numerical study was performed using OpenSees based on an experiment conducted in China. The 1x1, 2x2, and 2x3 rectangular EPC groups were modeled and validated by the test result. Each model is embedded in sand with a varied density and A different value of p-multiplier for each pile rows was considered. Monotonic pushover analysis was performed, and its inelastic behavior were investigated. All models suffer double plastic hinges on the leading row, located in connection and underground, depending on the soil density. The ratio of each pile row response to the average pile group response is an indicator to examine the forces distribution, influenced by p-multiplier only. The soil shear strength was investigated to observe the elasticity of soil when it reach its yield, ultimate, and the formed of plastic hinges. The p-multiplier and varied soil density affects the soil strength for pile rows, the denser the soil, the faster it reaches its plastic state. Overall, both p-multiplier and soil density affect inelastic behavior of foundations. Keywords: EPC, group foundation, plastic hinge, p-multiplier, pushover analysis
Studi Numerik Sambungan Spun Pile Terhadap Pile Cap Dengan Dan Tanpa Beton Pengisi Akibat Pembebanan Siklik Vania Callista; Yuskar Lase; Widjojo Adi Prakoso; Mulia Orientilize
TERAS JURNAL Vol 12, No 1 (2022): Volume 12 Nomor 1, Maret 2022
Publisher : UNIVERSITAS MALIKUSSALEH

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/tj.v12i1.681

Abstract

Abstrak Berdasarkan SNI 8460, spun pile sebagai struktur bawah didesain belum menggunakan konsep performance-based design (PBD) karena pertimbangan sulitnya proses perbaikan, meskipun PBD sudah diperbolehkan di negara lain. Peta gempa tahun 2017 menunjukkan adanya peningkatan seismic demand di Indonesia yang menyebabkan desain fondasi yang tidak efisien jika perilaku inelastic pada pondasi akibat gempa besar tidak diperbolehkan. Untuk mempelajari perilaku inelastic pondasi, tiga sambungan spun pile berukuran full scale diuji dengan pembebanan siklik horizontal. Analisis lanjutan dengan finite element (FE) dilakukan menggunakan Abaqus. Karena kurangnya jumlah tulangan geser (spiral) pada spun pile yang ada di Indonesia, efek confinement dari pemodelan tulangan spiral dibandingkan dengan pemodelan jika spiral disederhanakan sebagai hoops. Analisis FE juga dilakukan untuk mempelajari perbandingan perilaku antara spun pile kosong dan dengan beton pengisi dalam hal kekuatan, daktilitas dan performance levels dari sambungan spun pile.  Kata kunci: sambungan spun pile, performance-based design, the effect of concrete infill, daktilitas                                                   Abstract According to SNI 8640, spun pile as part of lower structure is not designed with the concept of performance-based design (PBD) because of repair issues, although PBD has been allowed for lower structures in other countries. According to the 2017 seismic zone, the increasing seismic demand in Indonesia results in an inefficient foundation design if inelastic behavior of foundation due to a big earthquake is not allowed. Three full scales of spun pile connections were tested with lateral cyclic loading to explore the inelastic behavior of foundation. A finite element (FE) analysis using Abaqus was conducted for further study. Due to low number of spun pile’s shear reinforcement (spiral) produced in Indonesia, the confinement effect of spiral model is compared with hoops model. Finite element analysis was also done to investigate the behavior difference of hollow spun pile and spun pile with concrete infill in terms of strength, ductility, and performance levels of spun pile’s connection. Keywords: spun pile connection, performance-based design, the effect of concrete infill, ductility
Benchmark for Country-Level Earthquake Strong-Motion Instrumentation Program Prakoso, Widjojo Adi; Sukanta, I Nyoman
Makara Journal of Technology Vol. 16, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

An empirical study to develop benchmark models at country-level to assess the suggested number of earthquake strongmotion stations based on a framework encompassing geographic, demographic, and socio-economic parameters is reported. The models are to provide a working estimate of the required number of stations for improving the strongmotion instrumentation program of Indonesia. National earthquake strong-motion networks of New Zealand, Japan, Taiwan, Iran, Turkey, and Italy were used as the references. The parameter proposed is the number of stations in land area of 1,000 km2, and three models based on the exponential regression analysis are presented as functions of population density, Gross Domestic Product (GDP) per capita, and the Global Competitiveness Index (GCI) Basic Requirements Index. Using the models, it is suggested that Indonesia would require at least 750 stations.
Experimental and Numerical Analysis of Spun Pile-to-Pile Cap Connection with Reinforced Concrete Infill under Cyclic Loading Alfetra Henoch Tandita; Yuskar Lase; Widjojo Adi Prakoso; Mulia Orientilize
Rekayasa Sipil Vol. 16 No. 3 (2022): Rekayasa Sipil Vol.16. No.3
Publisher : Department of Civil Engineering, Faculty of Engineering, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.rekayasasipil.2022.016.03.8

Abstract

Numerical study was conducted by using ABAQUS software to investigate two issues on spun pile connections. The issues are usage of non-shrinkage concrete infill cast inside hollow of pile and ductility. An experimental test was carried out to investigate the effect of two different concrete infill types which were common concrete fc’ 35 MPa and non-shrinkage concrete fc’ 54 MPa. A finite element model was validated against experimental test. The results were compared in terms of hysteresis curve, ductility, and performance level. Ductility is one of the important parameters to describe performance of spun pile connections under seismic load. There are different approaches to calculate ductility and this leads to four different ductility values. Hence, ductility of spun pile with concrete infill is in the range of 3.2 to 4.8. Behavior of spun pile with non-shrinkage concrete infill is slightly improved although the results were almost similar.
Modelling Study of Pile Group Foundation by Including Lateral Load in Clay Soil Muhammad Reza Imansyah; Widjojo Adi Prakoso; Mulia Orientilize
Indonesian Geotechnical Journal Vol. 2 No. 1 (2023): Vol.2 , No.1, April 2023
Publisher : Himpunan Ahli Teknik Tanah Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56144/igj.v2i1.22

Abstract

 Indonesia’s geographical condition causes earthquakes to occur more frequently. This study aims to investigate pile group response under earthquake loading by performing pushover analysis. Since clay soil is dominant and widespread in Indonesia, the study focused on pile group embedded in single layer of clay. The undrained shear strength (Su) parameters of the clay are varied from 20 kPa, to 100 kPa with 20 kPa intervals. The pile and soil were modelled by Beam-on-Nonlinear-Winkler-Foundation (BNWF), and the soil was presented as a series of Winkler springs using the nonlinear p-y method. The analysis was conducted with a finite element method (FEM) software, OpenSees. The pile was modelled as a fiber section, where the transversal and longitudinal reinforcement can be considered. The research found that the soil’s Su affects the ductility and formation of plastic hinge. Greater Su resulted in higher ductility and occurrence of plastic hinge. Higher Su was also found to increase the internal force experienced in the pile, as well as lead to higher group efficiency factor. There was no shear failure detected in the results, but bending failure happened at the lead pile in Su 100 kPa. The overturning moment phenomenon occurred on the pile group in Su 20 kPa and 100 kPa. For Su = 20 kPa, this phenomenon is caused by the middle pile and rear pile, which did not have optimal performance. Bending failure at the lead pile led to the phenomenonin Su 100 kPa.
ANALISA STATISTIK HASIL UJI KAPASITAS METODE DINAMIS (PDA TEST) PADA PONDASI TIANG PANCANG SISTEM PANCANG TEKAN Didik Haryadi; Widjojo Adi Prakoso
Wahana Teknik Sipil: Jurnal Pengembangan Teknik Sipil Vol 28, No 1 (2023): Wahana Teknik Sipil
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/wahanats.v28i1.4558

Abstract

The use of HSPD (Hydraulic Static Pile Driver) in deep foundation can reduce the level of noise and vibration as a result of pile driving. When a pile is hydraulically driven into the ground to the required axial compression capacity as recorded by a manometer installed on the HSPD equipment, a failure in this capacity is frequently observed after a dynamic verification test (PDA test). The purpose of this study is to determine the root cause of discrepancies in the axial compression capacity between results monitored by the HSPD equipment and dynamic test verification. This research examined SQ25 and SQ30 piles of 295 and 94 numbers respectively in the period of January 2020 to July 2022. Dynamic verification test indicated that 11% SQ25 and 7% SQ30 piles were problematic. Based on the linear regression analysis, the embedment of pile (Lp), final settlement (DFN), and frictional resistance (Rs) contribute an effect on the mentioned above discrepancy. For the problematic SQ25 and SQ30 piles, values of ̅̅̅ and ̅̅̅̅ ̅̅̅ are less than the ones for non-problematic piles. In contrary, the value of ̅̅̅̅̅̅ for problematic piles is larger than the one for non-problematic piles.
Co-Authors Alfetra Henoch Tandita Didik Haryadi Fathia Handayani Kamal I Nyoman Sukanta, I Nyoman Muhammad Reza Imansyah Orientilize, Mulia Vania Callista Yuskar Lase, Yuskar