Judul: Analisis Tekuk Kolom Bambu Hitam Sebagai Komponen Struktur Bangunan
Abstrak: Bambu merupakan salah satu alternatif biomaterial terbarukan yang dapat dikembangkan sebagai bahan konstruksi dan bersifat komplementer terhadap kayu. Bambu hitam (Gigantochloa atroviolaceae) merupakan tanaman yang tumbuh lurus dengan batang hitam kuat yang dapat dimanfaatkan sebagai bahan konstruksi. Penelitian ini bertujuan memberikan informasi terkait kapasitas tekuk dan nilai faktor tekuk bambu hitam pada kolom tunggal dan multikolom sebagai komponen struktur bangunan. Contoh uji yang digunakan merupakan bambu hitam dengan ukuran 4 dan 6 m serta ditambahkan data hasil pengujian sebelumnya dengan berukuran 1, 2, dan 3 m untuk analisis faktor tekuk. Pengujian tekuk dilakukan menggunakan mesin uji tekuk kolom bambu ukuran penuh kapasitas 100 ton. Nilai kapasitas tekuk tertinggi dimiliki oleh kolom rangkap empat berukuran panjang 1 m yaitu 207 kN, sedangkan kolom tunggal dengan panjang 6 m memiliki kapasitas tekuk terendah yaitu 3 kN. Hasil analisis faktor tekuk menunjukkan bahwa kapasitas tekuk karakteristik dan batas bawah 5% yang telah dikoreksi faktor tekuk aman digunakan dalam analisis struktur kolom bambu hitam., Bamboo is an alternative renewable biomaterials developed as a construction material and complementary to wood. Hitam Bamboo (Gigantochloa atroviolaceae) is a plant that can grow straight with intense black culm that can be used as construction materials. This study aims to Hitam Bamboo in single and multi-culm columns as components of building structures. The test samples used were Hitam bamboo with sizes of 4 and 6 m and added data from the results of previous tests with sizes of 1, 2, and 3 m for buckling factor analysis. Buckling testing is carried out using a full-size bamboo column buckling testing machine with a capacity of 100 tons. The highest buckling capacity value is owned by a four-culm column measuring 1 m long, 207 kN. In contrast, a single column with 6 m length has the lowest buckling capacity of 3 kN. The results of the buckling factor analysis showed that the characteristic buckling capacity and the lower limit of 5% corrected by buckling factor are safe for analyzing bambu hitam column structures.
Keyword: buckling capacity, buckling factor, column, hitam bamboo, multicolumn

Judul: Analisis Kekuatan Tekuk Kolom Bambu Tali (Gigantochloa apus (J.A. & J.H. Schultez) Kurz) dengan Variasi Panjang dan Jumlah Batang Penyusun Kolom
Abstrak: Bambu tali berpotensi dijadikan sebagai kolom. Tekuk merupakan titik kritis penyebab kegagalan struktur kolom dalam menahan beban tekan. Penelitian ini bertujuan mengetahui kekuatan tekuk maksimum kolom bambu tali dengan variasi panjang dan jumlah batang penyusun. Bambu tali diperoleh dari pasar komersial di Jl. Raya Dramaga, Bogor, Jawa Barat. Bambu dipotong menjadi ukuran 1, 2, dan 3 m. Pengukuran dimensi berdasarkan BS ISO 19624:2018, sedangkan pengukuran geometri berdasarkan BS ISO 22157:2019. Pengujian sifat fisis meliputi kadar air, kerapatan, dan kerapatan linear, serta pengujian mekanis yaitu kekuatan tekuk kolom bambu tali. Uji lanjut Duncan digunakan untuk membandingkan hasil pengujian tekuk kolom bambu tali dengan variasi panjang dan jumlah batang penyusun kolom. Contoh kolom berukuran 1 m, 2 m, dan 3 m. Pengujian tekuk kolom 1 m mengunakan UTM SATEC-Baldwin berkapasitas 30 ton, sedangkan pengujian tekuk kolom 2 m dan 3m menggunakan alat uji tekan berkapasitas 100 ton. Pengujian tekuk kolom dilakukan dengan memberikan pembebanan secara vertikal pada kolom. Pengolahan data faktor tekuk menggunakan Formula Ylinen’s. Kolom bambu panjang memiliki angka kelangsingan tinggi dan menghasilkan nilai tekuk rendah, sehungga kolom mudah mengalami tekuk. Kolom bambu tali komposisi ganda dua, tiga, maupun empat memiliki nilai kekuatan tekuk lebih tinggi dibandingkan jumlah kekuatan tekuk masing-masing batang penyusunnya karena adanya kerjasama antar komponen penyusun. Peningkatan kekuatan akibat kerjasama antar komponen penyusun ini dapat dinyatakan sebagai repetitive member factor (komponen struktur berulang) yang masih perlu diperhitungkan., Bamboo tali has the potential to be used as a column. Buckling is a critical point that causes the failure of the column structure to withstand compressive loads. This study aims to determine the maximum buckling strength of the bamboo tali column with variations in length and number of comonents. The bamboo tali was obtained from commercial market on Jl. Raya Dramaga, Bogor, West Java. The bamboo is cut into 1, 2, and 3 meters. Dimensional measurements are based on BS ISO 19624:2018, while geometric measurements are based on BS ISO 22157:2019. Physical properties tests include moisture content, density, and linear density, as well as mechanical testing, namely the buckling strength of the bamboo tali column. Duncan's further test was used to compare the results of the buckling test of bamboo tali columns with variations in length and number of components making up the column. The column test speciments are 1 m, 2 m, and 3 m. The 1 m sized columns are tested using UTM SATEC-Baldwin 30 tons capacity, while the 2 m and 3 m sized column were tested using compressive testing machine 100 tons capacity. The column buckling test is carried out by applying vertical loading to the column. Buckling factor data processing using Ylinen's Formula. Long bamboo columns have a high slenderness rate and produce a low buckling value, so that the column is prone to buckling. The the buckling strength of bamboo multicolumns are higher than the sum of single colunms buckling strengths because of the cooperation between the column’s components. The strength improvement because of the column’s components cooperation can be determined as repetitive member factor which should be considered.
Keyword: angka kelangsingan, kolom, multikolom, tali, tekuk, slenderness ratio, column, multicolumns, tali, buckling

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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