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"Seismic waves used for exploration of geological structures are mostly generated from blast sources. A new blasting vibroseis apparatus, which utilizes the homogeneity, isotropy, and incompressibility of water to reduce damage to adjacent rock from blast waves, was developed. This method overcomes the low repeatability and low control issues of traditional blast methods (downhole charge) while maintaining the advantages of high explosive power, sharp pulse signal, and a wide range of frequency domains. Blasting vibroseis and traditional blasting tests were implemented in the Three Gorges Reservoir Region, China. The finite element method (FEM) method was used to numerically calculate blasting vibroseis-induced dynamic ground pressures. Through a series of comparison tests, the characteristics of the seismic waves generated by blasting vibroseis were summarized and the repeatability and controllability of the blasting vibroseis test was validated. The blasting vibroseis apparatus was then used to detect geological structures below the surface of the Maoping landslide, China, and the results were very consistent with previous drilling exploration (89%), which reflects the practical value of the new blasting vibroseis for the exploration of geological structures. Blasting vibroseis can be used as a practical and cost-effective method to detect geological structures."

"ABSTRAKKombinasi beban gravitasi dan gempa pada desain struktur penahan gempa memberikan desain girder dengan kebutuhan tulangan tumpuan yang banyak dan tulangan lapangan sebaliknya. Hal ini dapat menimbulkan permasalahan, diantaranya adalah kesulitan pelaksanaan akibat padatnya tulangan pada tumpuan girder dan keretakan pada lapangan girder akibat sedikitnya tulangan terpasang. Salah satu solusi yang ditawarkan adalah melakukan redistribusi momen. ACI318 mengijinkan penerapan redistribusi momen dengan mengurangi momen negatif maksimum dan mendistribusikannya ke daerah momen positif maksimum, dengan derajat redistribusi maksimum adalah 20%. Penelitian ini bertujuan untuk menganalisis efek penerapan redistribusi momen terhadap kinerja global dan lokal struktur. Pada penelitian ini empat struktur bangunan tahan gempa didesain sesuai ASCE 7-16, yaitu: (1) model M8, struktur gedung 8 lantai dengan denah lantai simetris, (2) M8A, struktur gedung 8 lantai dengan denah lantai asimetris, (3) M12, struktur gedung 12 lantai dengan denah lantai simetris, dan (4) M8L, model 8 lantai dengan geometri denah berbentuk L. Dari setiap model dikembangkan 4 model berbeda, dengan variasi tingkat redistribusi momen dan lokasi penerapannya. Analisis nonlinear riwayat waktu sesuai dengan ASCE 41-17 dilakukan terhadap hasil desain elastis. Hasil yang didapatkan adalah terjadi penurunan kekuatan, kekakuan, dan kinerja struktur secara global serta lokal komponen struktur, namun kinerja global dan kinerja lokal struktur masih berada pada tingkat kinerja desain awal.

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ABSTRACTCombination of gravity and seismic loads on a reinforced concrete seismic resisting structure leads to the needs of large number of rebar at the support and small number of rebar at mid-section of a girder. This leads to potential problems such as congestion at the support and cracking at girder's mid-section. ACI318 allows the application of moment redistribution by reducing the maximum negative moment and distribute it to maximum positive moment with maximum allowed redistribution is 20%. This study is done to investigate the effect of moment redistribution to global and local components' performance. Four models designed in accordance to ASCE 7-16 are developed, that is: (1) 8-story reinforced concrete (RC) building with symmetrical floor plan, (2) 8-story RC building with unsymmetrical floor plan, (3) 12-story RC building with symmetrical floor plan, and (4) 8-story RC building with L-shaped floor plan. From each models four variations will be developed based on moment redistribution degree and its location. Nonlinear time history analysis in accordance to ASCE 41-17 is done to all models. The result obtained from this study shows that there is reduction in the strength, stiffness, and peformance level of the global and local component performances, yet the global and local components' performance is still inside the range of acceptable response."

"[Penelitian ini membahas mengenai analisis perilaku dinamik struktur bangunan tahan gempa dengan perletakan terisolasi dengan cara membandingkannya dengan bangunan dengan perletakan tetap. Bangunan dengan perletakan terisolasidimodelkan dengan menggunakan base isolation yang sesuai dengan yang digunakan oleh rumah sakit UI, sementara bangunan dengan perletakan tetap dimodelkan dengan menggunakan perletakan jepit. Beban gempa yang digunakanadalah beban gempa riwayat waktu northridge, kobe, dan el-centro yang telah diskalakan dengan respon spektrum Depok sesuai dengan SNI 1726:2012 Tata cara perencanaan ketahanan gempa untuk struktur gedung dan non gedung.Analisa yang digunakan yaitu nonlinear time history direct integration. Nonlinearitas dari bangunan didapatkan dari material dan geometri yang diwakilkan oleh sendi plastis pada bangunan dengan perletakan tetap dan base isolator yang telah berdeformasi melebihi batas lelehnya pada bangunan dengan perletakan terisolasi. Dari hasil penelitian menunjukkan penggunaan base isolator pada struktur bangunan tahan gempa meningkatkan peforma bangunan akibat beban gempa, serta memperkecil gaya dalam element-element struktur bangunan.

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This study discusses the comparison of the dynamic behaviour analysis of the isolated base seismic structure and fixed base structure. The isolator used in the mathematical model of the isolated base structure in this study is the same with the isolator that will be used in the real UI Hospital Building, while the fixed base structure modeled by rigid base. The seismic load used in this study are time history seismic load of Northridge, Kobe, and El Centro. The time history is scaled by the factor appropriate with SNI 1726:2012. Nonlinear time history direct analysis method will be performed in this study. The nonlinearity of the structure consists of geometrical nonlinearity and material nonlinearity gained

from the plastic hinge and the deformation of the isolator that exceed its yield deformation point. Result shows that isolated base structure has better performances than fixed base structure. It showed by the decreasing amount of the

internal forces of each elements of the structure.;This study discusses the comparison of the dynamic behaviour analysis of the isolated base seismic structure and fixed base structure. The isolator used in the mathematical model of the isolated base structure in this study is the same with the isolator that will be used in the real UI Hospital Building, while the fixed base structure modeled by rigid base. The seismic load used in this study are time history seismic load of Northridge, Kobe, and El Centro. The time history is scaled by the factor appropriate with SNI 1726:2012. Nonlinear time history

direct analysis method will be performed in this study. The nonlinearity of the structure consists of geometrical nonlinearity and material nonlinearity gained from the plastic hinge and the deformation of the isolator that exceed its yield deformation point. Result shows that isolated base structure has better performances than fixed base structure. It showed by the decreasing amount of the

internal forces of each elements of the structure.;This study discusses the comparison of the dynamic behaviour analysis of the

isolated base seismic structure and fixed base structure. The isolator used in the

mathematical model of the isolated base structure in this study is the same with

the isolator that will be used in the real UI Hospital Building, while the fixed base

structure modeled by rigid base. The seismic load used in this study are time

history seismic load of Northridge, Kobe, and El Centro. The time history is

scaled by the factor appropriate with SNI 1726:2012. Nonlinear time history

direct analysis method will be performed in this study. The nonlinearity of the

structure consists of geometrical nonlinearity and material nonlinearity gained

from the plastic hinge and the deformation of the isolator that exceed its yield

deformation point. Result shows that isolated base structure has better

performances than fixed base structure. It showed by the decreasing amount of the

internal forces of each elements of the structure., This study discusses the comparison of the dynamic behaviour analysis of the

isolated base seismic structure and fixed base structure. The isolator used in the

mathematical model of the isolated base structure in this study is the same with

the isolator that will be used in the real UI Hospital Building, while the fixed base

structure modeled by rigid base. The seismic load used in this study are time

history seismic load of Northridge, Kobe, and El Centro. The time history is

scaled by the factor appropriate with SNI 1726:2012. Nonlinear time history

direct analysis method will be performed in this study. The nonlinearity of the

structure consists of geometrical nonlinearity and material nonlinearity gained

from the plastic hinge and the deformation of the isolator that exceed its yield

deformation point. Result shows that isolated base structure has better

performances than fixed base structure. It showed by the decreasing amount of the

internal forces of each elements of the structure.]"

"Lapangan FM merupakan salah satu lapangan penghasil hidrokarbon yang terletak di Cekungan Jawa Barat Utara. Salah satu Formasi yang berpotensi sebagai penghasil hidrokarbon adalah Formasi Cibulakan berupa batupasir dan batugamping yang menjadi reservoar objektif. Untuk memprediksi penyebaran reservoar batupasir digunakan metode multi-atribut seismik. Metode multi-atribut merupakan metode untuk memprediksi reservoar. Prediksi tersebut didapat dari hubungan fisis diaplikasikan dengan properti atribut dari data seismik. Berdasarkan analisa crosplot diketahui bahwa log gamma-ray dan density merupakan parameter yang sensitif terhadap keberadaan reservoar batupasir. Metode multi-atribut digunakan dalam membuat volume pseudo gamma-ray dan density. Kombinasi antara gamma-ray dengan density dapat memisahkan dengan baik antara batupasir, batu gamping dan batu lempung. Hasil pemetaan menunjukkan reservoar batupasir terdistribusi pada daerah Tinggian. Hasil penelitian ini dapat digunakan untuk eksplorasi lebih lanjut dalam penyebaran reservoar pada Formasi Cibulakan di Lapangan FM.

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Field FM is one of the hydrocarbon-producing field located in the North West Java Basin. One of the potential formation of hydrocarbon-producing formations are sandstones and limestones Cibulakan form the reservoir objective. To predict the spread of reservoir sandstones research using multi-attribute seismic methods. Multi-attribute method is a method for predicting reservoir parameters. The predictions obtained from the physical relationship was applied to the property attribute of the seismic data.

Based on the analysis crosplot known that gamma-ray logs and density are parameters which are sensitive to the presence of reservoir sandstones. Multi-attribute method is used to predict the pseudo volume of gamma-ray and density. The combination of gamma-ray logs with density can separate well between sandstone, limestone and claystone.

Mapping results indicate reservoir sandstones in the area of distributed Tinggian. The results can be used for further exploration in the spread of the Formation reservoir in the Field Cibulakan FM."

"Penelitian ini membahas mengenai penggunaan Infrasonic Cleaner yang memanfaatkan gelombang infrasonik untuk membersihkan jelaga yang menempel pada pipa-pipa alat pemindah kalor pada boiler, yaitu economizer. Gelombang infrasonik diyakini mampu menimbulkan turbulensi pada sekitar partikel jelaga sehingga jelaga tidak mampu menempel kembali pada pipa. Skripsi ini akan menampilkan teori perpindahan panas dan efisiensi dari alat pemindah kalor, serta implementasi infrasonic cleaner pada boiler. Diperoleh hasil berupa peningkatan kinerja economizer sebesar 0,59 untuk unit A dan 0,57 untuk unit B. Untuk efisiensi boiler, terdapat peningkatan rasio ton uap dengan ton bahan bakar sebesar 0,70 0,38 menandakan kinerja yang lebih optimal.

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This thesis will discuss about the use of Infrasonic Cleaner that utilize infrasonic wave to clean ashes sticking on an economizer. This thesis will present the temperature input and output at economizer, so then a graphical presentation can be displayed. As the results, there is an increase of economizer efficiency up to 0,59 for unit A and 0,57 for unit B. There is also a noticeable increase of boiler efficiency by looking at the increase of ton steam and ton fuel ratio up to 0,70 0,38."

"Penelitian ini bertujuan untuk mengkarakterisasi kecepatan gelombang S sehingga dapat mengidentifikasi zona lemah pada zona produksi underground Grasberg Block Cave (GBC) dengan menggunakan metode Ambient Noise Tomography (ANT). Data yang digunakan berasal dari 11 sensor mikroseismik dengan frekuensi 15 Hz. Penelitian dilakukan dengan membandingkan data Ambient Noise Tomography (ANT) setelah 16 hari dilakukan proses produksi, yaitu data pada tanggal 1 April 2019 dengan data pada tanggal 16 April 2019. Selain mengkarakterisasi kecepatan gelombang S, hasil dari metode ANT ini dapat digunakan untuk melihat bahaya seismik jangka pendek dan jangka panjang pada tambang underground Grasberg Block Cave (GBC). Berdasarkan penelitian yang dilakukan, penulis mendapati terdapatnya perubahan kecepatan gelombang shear yang cukup besar pada zona produksi sebagai akibat dari proses penambangan pada area caving PB 1 tambang underground Grasberg Block Cave (GBC) yang berpotensi menyebabkan rockbrust.

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This research aims to characterize the S wave velocity for identify a weak zones in the production zone of the Underground Grasberg Block Cave (GBC) using the Ambient Noise Tomography (ANT) method. This research uses data from 11 microseismic sensors with a frequency of 15 Hz. The research was conducted by comparing the Ambient Noise Tomography (ANT) data after 16 days of the production process, that is data on April 1, 2019 with data on April 16, 2019. Apart from characterizing the speed of the S wave, the results of the ANT method can be used to see short-term and long-term seismic hazards at the Grasberg Block Cave (GBC) underground mine. Based on the research, the results show a large change in shear wave velocity in the production zone due to the mining process in the PB 1 caving area of the Grasberg Block Cave (GBC) underground mine and has the potential for rockbrust.

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"Migrasi Seismik merupakan salah satu proses akhir dalam prosessing seismik yang berfungsi untuk memindahkan kedudukan reflektor pada posisi dan waktu pantul yang sebenarnya. Migrasi yang digunakan dalam penelitian ini adalah migrasi geser-fase dan fourier split-step. Migrasi ini bekerja dalam domain frekuensi-bilangan gelombang dan mempunyai kemampuan untuk memigrasi struktur dip sampai 90o. Namun pada struktur yang memiliki perubahan kecepatan secara lateral, metode ini kurang mampu menanganinya. Metode geser-fase dan fourier split-step dicoba untuk melihat hasilnya dan ternyata metode fourier split-step mempunyai kemampuan yang lebih baik dalam menangani perubahan kecepatan secara lateral dibandingkan dengan metode geser-fase.

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Seismic migration is a part of final process in seismic processing that have a function to move the reflector to the true position. Migration method that is used in this thesis is phase-shift and split-step fourier migration. This migration works in frequensi-wave number domain and has the ability to migrate the structure that has dip until 90o. But for the structure that has lateral velocity variation, this method is less to handle it. Phase-shift and split-step fourier is used to migrate seismic data and the result is split-step fourier migration has the ability to handle lateral velocity variation more than phase-shift migration."