Dinamika Rekayasa (E-Journal - Engineering Departement Jenderal Soedirman University UNSOED)
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Penurunan Nilai Half Cell Potential Beton dengan Bahan Tambah FlyAsh dan Ca(C18H35O2)2
Get PDFSerangan korosi pada tulangan baja di dalam beton bertulang dapat diinisiasi oleh ion klorida. Semakin banyak ion klorida yang meresap ke dalam beton, laju korosi pada beton bertulang semakin tinggi. Tingkat Ke-potensi-an korosi ini bisa diukur dengan melakukan uji half cell potential. Fly ash merupakan bahan yang mempunyai butir lebih halus dibanding semen mampu memperkecil diameter kapiler beton. Sementara itu senyawa stearate bila diaplikasikan pada beton mampu meningkatkan ke-hydrophobic-an beton. Studi ini meneliti tentang pengaruh penggunaan fly ash dan calcium sterarate / Ca(C18H35O2)2 pada beton. Investigasi ini menggunakan benda uji balok beton bertulang ukuran 11.4 x 15.2 x 28.0 cm sebanyak 15 buah. Baja tulangan yang digunakan merupakan baja ulir diameter 16 mm. Dua buah tulangan dalam balok beton bertulang yang terletak dibawah berfungsi sebagai katoda dan satu buah tulangan yang terletak di atas berfungsi sebagai anoda. Hasil uji half cell potential menunjukkan bahwa beton dengan kandungan fly ash dan calcium stearate dapat menurunkan tingkat kepotensian beton dari serangan korosi.Â
Perilaku Sambungan Balok-Kolom Pracetak Bataton Berdasarkan Metode Eksperimental
Get PDFKonstruksi pracetak banyak digunakan di Indonesia karena memiliki beberapa keunggulannya. Sistem pracetak bataton memiliki keunggulan pengurangan global warming karena mengurangi pemakaian bekisting. Sistem pracetak memiliki kelemahan pada sambungan sehingga sambungan didesain agar berperilaku dengan baik dalam mentransfer beban. Tujuan penelitian ini untuk mengetahui karakteristik sambungan balok-kolom akibat beban siklik dengan program pembebanan berdasarkan ACI T1.1-01 yang mensimulasikan beban gempa. Hasil pengujian diperoleh beban lateral maksimum rerata sampel monolit sebesar 26,45 kN, sedangkan pracetak terjadi penurunan 17,58%. Kekakuan rerata sampel monolit pada saat leleh sebesar 0,52 kN/mm, sedangkan kekakuan pracetak terjadi penurunan 32,69%. Hysteretic loop sampel monolit lebih besar dibandingkan dengan pracetak, hal ini menunjukkan sampel (M) memiliki disipasi energi yang lebih besar. Hubungan antara hysteretic energy (HE) dan potential energy (PE) terhadap siklus pengujian menunjukkan sampel monolit memiliki HE dan PE lebih besar jika dibandingkan pracetak. Nilai rerata EVDR monolit dan pracetak berkisar antara 6% -14%. Menurut Pas (1990), rasio redaman pada sistem struktur biasanya teredam
Penyelesaian Permasalahan Penjadwalan Aktivitas Proyek dengan Batasan Sumber Daya Menggunakan Metode Cross Entropy
Get PDFProject scheduling is essential to be planned before activities. Standard methods of project scheduling based on precedence constraints scheduling events and the assumption that resources are not unlimited capacity. But in fact the project activity has resource limits. The main objective is to minimize the total duration of the project with precedence constraints and resource constraints for all project activities. Many optimization methods are used to improve the quality of scheduling and speed up the calculation time. This paper proposed the use of Cross Entropy (CE) method to solve resource constraints project scheduling problem, as well as comparing the advantages and disadvantages between the CE methods with Differential Evolution (DE) method. The purpose CE method consist of four critical steps including generating a sample of random solution, calculating the performance according to the specific fitness function, selecting elite sample and finally updating the previous parameters to get a better sample in the next iteration. To speed up the computation time, in this study decrease the number of samples for each iteration in Cross Entropy algorithm. Numerical experiments with several data sets from the Project Scheduling library (PSPLIB) showed that CE can provide the optimal total duration of the project same as the DE with calculation time is faster than DE
Tahanan Lateral Bambu Laminasi dengan Konektor Pelat Disisipkan Menggunakan Sambungan Baut
Get PDFAnalisis tahanan lateral beberapa alat sambung telah diusulkan Europen Yield Model (EYM) tahun 1949. Beban leleh berupa nilai tahanan lateral (Z) dapat diprediksi dengan mengetahui nilai geometri sambungan, tegangan leleh dowel dan kuat tumpu dowel. Pengujian tahanan lateral ini dilakukan dalam rangka mengetahui kemampuan sebuah baut dengan model sambungan pelat besi disisipkan pada bambu laminasi. Tahanan lateral sejajar dan tegak lurus arah serat-serat dibutuhkan dalam merencanakan sambungan struktural. Pada uji tahanan lateral ini dibedakan menjadi dua, tahanan lateral tegak lurus serat dan tahanan lateral sejajar serat. Dimensi benda uji tahanan lateral tegak lurus serat adalah 2 buah balok bambu laminasi dengan dimensi 37,5×76×180 mm, dan dimensi tahanan lateral sejajar serat 83×76×200 mm. Hasil penelitian menunjukkan teori Yield Mode dari EYM dapat memprediksi nilai tahanan lateral bambu laminasi. Perbedaan hasil ekperimen sebesar 8,05% lebih tinggi dari teori yield mode pada tahanan lateral tegak lurus serat dan 8,38% pada tahanan lateral sejajar serat. Nilai Poffset 5% sebesar 12,34 kN selip pada 4,82 mm dan kekakuan rata-rata sebesar 3,050 kN/mm pada tahanan lateral tegak lurus serat. Uji tahanan lateral sejajar serat memiliki nilai Poffset 5% rata-rata sebesar 20,3 kN dan kekakuan awal sebesar 6,144 kN/mm pada nilai selip rata-rata 3,99 mm
Identifikasi Lapisan Geologi Bawah Permukaan Berdasarkan Data Geomagnetik di Sungai Logawa Banyumas
Get PDFIdentification of geological resources can be done either using surface mapping and cross sectional stratigraphy measurement or geophysical approximation beneath the earth surface. Geomagnetic exploration related to the existing of gold mineral begins with the total magnetic field intensity measurements at 173 locations was scattered in 109.196970 - 109.207580E and 7.448830 - 7.454110S. Interpretation from processing of data obtained four anomalous object, which is defined as fine-medium sandstone (χ= 0.0015 cgs units), coarse sandstone and compact (χ= 0.0035 cgs units), igneous basalt-andesite old Slamet (χ= 0.0085 cgs units), and the complex bedrock (χ= 0.0145 cgs units). The presence of gold mineralization in the rock throughout geomagnetic surveys used to identification of subsurface geological which is interpreted from the processing data that indicated the presence of gold in association with sedimentary (sandstone) is often referred to as sediment-hosted
Penilaian Risiko Keselamatan Dan Kesehatan Kerja
Get PDFKeselamatan dan kesehatan kerja merupakan aspek penting dalam mengendalikan semua risiko yang ada didalam operasional perusahaan sehingga Penerapan (K3) ditempat kerja dapat meminimalkan risiko kecelakaan kerja pada setiap kegiatan proses produksi. Kecelakaan yang terjadi di lingkungan kerja sebagian besar 88% disebabkan karena perilaku yang tidak aman (unsafe action), 10% kondisi lingkungan kerja yang tidak aman (unsafe condition) dan 2% tidak diketaui penyebabnya. Oleh karena itu manajemen perusahaan harus melakukan analisis terhadap manajemen risiko yang diharapkan dapat mengurangi dan melindungi bahkan menghilangkan risiko kecelakaan kerja (zero Accident) pada tenaga kerja dengan melakukan pencegahan pada timbulnya kecelakaan kerja selama melakukan kegiatan proses produksi. Tujuan penelitan ini yaitu melakukan identifikasi potensi bahaya dan melakukan penilaian risiko bahaya yang akan terjadi di PT. X divisi Particle Board di area glue kitchen, forming dan press line. Terdapat 23 kejadian risiko keselamatan dan kesehatan kerja yang sudah di identifikasi. Adapun risiko yang paling banyak terjadi yaitu pada tahapan proses forming dan press process. Tingkat risiko yang paling tinggi yang bisa berpotensi kematian (ektstrem risk) yaitu ketika pekerja melintasi tangga forming dan hot press. Sedangkan tingkat risiko yang paling rendah yaitu ketika pekerja terbentur besi beam, terkena flake yang tajam dan terkena oli panas saat terjadi kebocoran pipa
Analisis Probabilitas Kecepatan Angin untuk Pesisir Cilacap dengan Menerapkan Distribusi Weibull dan Rayleigh
Get PDFWind characteristics especially the event probability have been more studied in the relation to wind energy availability in an area. Nevertheless, in the relation to coastal structure, it is still rare to be unveiled in a paper particulary in Indonesia. In this article, therefore, it is studied probability distribution commonly used to wind energy analysis i.e. Weibull and Rayleigh distribution. The distribution is applied to analyze wind data in Cilacap Coast. Wind data analyzed is from Board of Meteorology, Climatology and Geophysics, Cilacap branch, along two years (2009 – 2011). Mean, varians and standard deviation are founded to calculate shape factor (k) and scale factor (c) which must be available to arrange distribution function of Weibull and Rayleigh. In the region, it gains a result that wind speed probabilities follow Weibull and Rayleigh function fairly. Shape parameter value has been gotten k = 3,26, while scale parameter has been gotten respectively c = 3,64 for Weibull and Cr = 2,44 for Rayleigh. Value of k ≥ 3 indicates the region has regular and steady wind. Besides, mean speed of wind is 3,3 m/s
Analisis Pencahayaan Ruang Kerja: Studi Kasus Pada Usaha Kecil Mikro dan Menengah (UMKM) Batik Tulis di Yogyakarta
Get PDFA good workspace significantly affects on work productivity. Therefore, in designing a workspace, it is necessary to put much concern on lighting condition. A good condition on it can make workers comfortable during their activities and further increase productivity.This research shows data taken from real-lighting condition in small-medium handmade Batik industry,namely Batik Sogan which is located in Yogyakarta. The object of this research is a workspace with some working activities for example sewing, over edge sewing, and buttons attachment. With Dialux 4.8 software, the research is conducted to compare between direct measurement and lighting simulation result, as well as giving recommendation to improve lighting condition which fits in standards. The result shows that the lighting condition in Sewing-room in Batik Sogan is below standard, i.e., 91 – 125 lux. Therefore, sewing-room condition must be improved, so that the lighting condition may meet the standardized lighting for working conditions which is 500-1000 lux. Simple and cheap improvement to it are to replace the type of the lamp into Philips 4MX091 TL as many as 4 items and to change the colour of the rooms and the desks into white, so it can achieve the maximum lighting 693 lux, which has met the minimum standards for rather- soft working lighting
Analisis Balok Beton Bertulang Tampang T Yang Diperkuat Dengan Wire Rope Menggunakan Program Response-2000 Dan Metode Pias
Get PDFThis study aims at finding out the comparison of the results of analysis using Response-2000 and discrete element method and of experiment on T-section reinforced concrete beam strengthened using wire rope. The modeling was made on two T-section beams, where one beam was without strengthening and another beam was with strengthening using two wire ropes of 10mm. Results indicate that the ratios of increase in flexural capacity as results of the analysis using Response-2000 and discrete element method compared to results of the experiment for the control beam were 1.01 and 1.04, respectively, while the ratios of decrease for the strengthened beam were 0.84 and 0.87, respectively. A ductility index for the control beam as result of the analysis using Response- 2000 and discrete element method decreased compared with results of the experiment with ratios of 0.31 and 0.60, respectively. A ductility index for the strengthened beam as result of the analysis using Response-2000 and discrete element method increased compared with results of the experiment with ratios of 1.19 and 1.92, respectively. The ratios of increase in the initial stiffness as result of the analysis using Response-2000 and discrete element method compared with result of the experiment for the control beam were 2.85 and 3.33, respectively, and the ratios of increase in equivalent stiffness as result of the analysis using Response-2000 and discrete element method were 1.62 and 1.42, respectively. The ratios of increase in initial stiffness for the strengthened beam as result of the analysis using Response-2000 and discrete element method compared with result of the experiment were 3.70 and 5.26, respectively, while those for equivalent stiffness were 3.16 and 2.75, respectively
Studi Potensi Sumberdaya Andesit Menggunakan Metode Geolistrik Di Daerah Kokap, Kabupaten Kulonprogo, Daerah Istimewa Yogyakarta
Get PDFThe study of andesite resources was carried out in Hargowilis village, Kokap sub-district, Kulonprogo regency, Daerah Istimewa Yogyakarta province using geoelectrical data with Schlumberger configuration, as much as 14 point which is spreading on 8 hectares area. Based on regional geological map of Yogyakarta area, study area include on intrusive rock lithology’s unit compose of hipersten andesite to augite-hornblende andesite and trachiandesite. Geoelectrical method is one of geophysical method that used to observed geological condition in subsurface based on rock’s electrical properties. Andesite is one type of igneous rock which have contrast electrical properties with its surrounding rock, generally sedimentary rocks, makes it suitable for geoelectrical method to identify the presence of andesite in subsurface and also estimate its thickness to calculate the resources. Geoelectrical configuration used is 1D Schlumberger configuration where this method have advantage more accurate to calculate the thickness of rock layer especially in shallow area. The result of geoelectrical survey showing that it consist 2 layer of andesite, there are shallow layer and deep layer. This result indicate that the igneous rock in study area not only intrusion type, but also lava flow type. Resources potential of andesite both shallow and deep layer are 5,072,354 tons and resources potential of shallow andesite only is 3,162,566 tons