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Studi Eksperimental terhadap Parameter Daktilitas Struktur Baja
Full text linkAbstrak. Makalah ini menyajikan studi eksperimental terhadap daktilitas struktur baja berupa portal sederhana dengan tujuan meneliti parameter-parameter yang berpengaruh terhadap daktilitas struktur baja, dan melakukan validasi terhadap usulan formula daktilitas struktur yang sedang dikembangkan melalui studi numerik. Sebelum dilakukan pengujian di Laboratorium terlebih dahulu dilakukan penelusuran teori-teori serta data-data dari hasil-hasil penelitian sebelumnya. Selanjutnya dilakukan simulasi komputer dengan menggunakan paket program analisis nonlinier MSC/NASTRAN untuk mengetahui parameter-parameter yang berpengaruh secara signifikan terhadap daktilitas struktur portal baja sederhana. Hasil penelitian menunjukkan bahwa properti penampang (bf/2tf, h/bf), perbandingan tinggi kolom struktur dengan tinggi profil (H/h), serta tinggi kolom dengan lebar bentang struktur (H/L) merupakan parameter yang sangat berpengaruh terhadap nilai daktilitas. Validasi terhadap formula daktilitas yang diusulkan melalui studi numerik menunjukkan bahwa hasil numerik lebih bersifat konservatif, namun hasil analisis numerik dan eksperimen menunjukkan pola kurva daktilitas yang sama.Abstract. This paper presents experimental study of ductility parametric of steel structure. The purpose of this research to investigate the parametric influencing ductility of steel structure and to validate ductility formula obtained from numerical study. For this purpose, experimental data and modeling of specimen obtained from previous study and through simulation by nonlinear program MSC/NASTRAN. The result of investigation shows that: behavior of cross section (bf/2tf, h/bf), ratio height and width of structure (H/L) have great influence on the available ductility of steel structure. Validation of ductility formula show that the ductility the ductility value by experimental study is higher than numerical study, but the curve of ductility ratio shows the same behavior between experimental and numerical result
KAJIAN NUMERIK DAN EKSPERIMENTAL PADA STRUKTUR DENGAN CORE FRAME MENGGUNAKAN COUPLING BEAM DAN REPLACEABLE LINK
No full textAbstrak
Kinerja link pada struktur core rangka baja dengan balok perangkai dan link pada bangunan bertingkat 10 dibahas melalui kajian numerik dan eksperimental. Kajian numerik dilakukan dengan analisis non-linier statik dan dinamik terhadap sejumlah link dengan variasi panjang, tebal pelat sayap, dan tebal pelat badan; dengan mempertahankan elemen struktur core frame lainnya tetap elastik. Hasil kajian terhadap kekakuan, kekuatan, daktilitas, disipasi energi, dan mekanisme kelelehan struktur core menunjukkan penggunaan link geser pada struktur core dengan penebalan web memberikan kelebihan dibandingkan dengan penggunaan link lentur, dan menunjukkan kemampuan memikul gaya geser gempa yang tidak banyak berkurang dibandingkan struktur core tanpa link. Kajian eksperimental berupa pembebanan siklik terhadap sistem core rangka baja dengan balok perangkai dan link geser yang dapat diganti, menunjukkan link geser dengan penebalan pelat badan memberikan kinerja seismik yang lebih baik.
Kata Kunci : Link yang dapat diganti, link geser, balok perangkai, struktur core rangka baja, kinerja seismik
Abstract
Numerical and experimental work are conducted to study the performance of steel core frame with coupling beam and link of a 10th story building. Non-linear static and dynamic analyses are carried out to a number of core frames with links of various length, flange thickness, and web thickness, while maintaining the other elements remain elastic. The analysis of stiffness, strength, ductility, energy dissipation, and yielding mechanism of core structure shows the advantage of shear link with increasing web thickness compared to flexural link, and shows slightly less base shear compared to core frame without link. Experimental work with cyclic loading to a half-scaled core frame with coupling beam and replaceable link shows a better seismic performance of a shear link with increasing web thickness .
Keywords: Replaceable link, shear link, coupling beam, core frames, seismic performance.
Replaceable Link merupakan sebuah istilah untuk elemen link beam yang dihubungkan oleh coupling beam pada sistem struktur core yang didesain dapat diganti jika mengalami kelelehan. Sifat inelastik struktur hanya direncanakan pada link beam, sehingga elemen lain seperti kolom dan coupling beam tetap bersifat elastik. Kajian numerik dilakukan untuk mempelajari kinerja struktur terhadap kekakuan, daktilitas, disipasi energi dan mekanisme kelelelehan. Struktur ini dianalisis dengan memvariasikan link terhadap penebalan web, penebalan flange, dan penambahan panjang. Struktur ini dibandingkan dengan struktur serupa tanpa link sebagai benchmark. Hasil studi menunjukkan struktur dengan konsep replaceable link memiliki kinerja yang baik jika direncanakan menggunakan link geser. Kinerja struktur dengan variasi penebalan web dan flange memiliki kekakuan elastik struktur yang sama dan disipasi energi meningkat, tetapi menurunkan daktilitas. Penebalan web pada link geser meningkatkan kekakuan inelastiknya. Penambahan panjang link memiliki kekakuan cenderung sama dan meningkatkan daktilitas serta disipasi energi. Struktur yang optimal sesuai konsep replaceable link memiliki kapasitas base shear maksimum mencapai 95% dari struktur tanpa link serta memiliki daktilitas dan disipasi energi yang lebih baik daripada struktur tanpa link.
Dari kajian numerik yang dilakukan terlihat variasi penebalan web pada link geser merupakan variasi yang baik karena dapat meningkatkan kekakuan dan disipasi energi serta tidak perlu merubah konfigurasi struktur. Oleh karena itu, dilakukan kajian eksperimental pada struktur ini dengan variasi tebal web pada link. Kajian eksperimental dilakukan terhadap half-scale struktur yang terdiri dari kolom, coupling beam dan link beam. Sub-assembly diuji dibawah pembebanan siklik sesuai dengan ketentuan AISC 341-10 dengan mengkonversi rotasi menjadi displacement. Inovasi dilakukan pada link beam dengan cara melakukan penebalan pada bagian web link. Link-1 digunakan profil W150x75x6x8 sedangkan untuk Link-2 digunakan penampang link dengan profil W150x75x8x8. Pengujian diamati berdasarkan displacement kontrol yang direncanakan pada kolom sub-assembly dengan pembebanan lateral melalui aktuator. Hasil pengujian menunjukan bahwa penebalan yang dilakukan pada web link terbukti dapat meningkatkan disipasi energi sebesar 47% dan kekakuan elastik link dengan presentase rata-rata sebesar 42% tanpa menyebabkan kelelehan pada elemen lain seperti kolom, coupling beam dan sambungan link
Kajian Eksperimental Peningkatan Kinerja Link Geser pada Sistem Rangka Baja Berpengaku Eksentrik
Full text linkAbstrak. Link geser pada sistem rangka baja berpengaku eksentrik (SRBE) merupakan elemen utama penyerap energi gempa yang direncanakan mengalami leleh pada seluruh pelat badannya. Kinerja link geser dengan sambungan baut yang berkurang akibat terjadinya kegagalan pada pelat sayap, diperbaiki dengan dua cara: (1) memperlebar pelat sayap pada bagian ujung link, dan (2) meningkatkan mutu pelat sayap. Kajian eksperimental dilakukan terhadap tiga buah link geser yaitu link bench-mark, link dengan pelebaran sayap, dan link dengan peningkatan mutu pelat sayap. Pembebanan siklik secara kuasi-statik dengan kontrol perpindahan dilakukan terhadap ketiga spesimen link hingga mencapai keruntuhan. Kurva histeretik yang dihasilkan menunjukkan peningkatan kinerja yang signifikan pada kedua upaya perbaikan, meliputi: kekuatan, daktilitas, dan disipasi energi.Abstract. Shear link of the eccentrically braced steel frames is the major seismic energy dissipating element which is expected to yield in its entire web. The decreasing performance of bolt-connected shear link due to failure of its flange, is improved by two methods: (1) widening the flange at link ends, and (2) increase the grade of flange. Experimental work was carried out on bench-mark link, link with wing plate, and link with flange of higher grade. Series of quasi-static cyclic loading with displacement control were applied to each link until its failure. Hysteretic curve shows increasing performance by both improvement methods, which includes: strength, ductility, and energy dissipation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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