Hasil Pencarian  ::  Simpan CSV :: Kembali

"Dengan sekitar 48,42 juta ton produksi kelapa sawit pada tahun 2019, Indonesia menjadi produsen terbesar kelapa sawit terbesar di dunia. Dengan demikian, pemanfaatan cangkang kelapa sawit sebagai pengganti agregat kasar tentu dapat mengurangi limbah yang dihasilkan industri kelapa sawit. Pada penelitian ini, penulis mengamati nilai lendutan, regangan, rasio redaman dan frekuensi alami dari balok beton bertulang dengan agregat kasar cangkang kelapa sawit (Oil Palm Shell/OPS) berukuran 15 x 25 x 300 cm³ (dengan jarak 2,7 meter dari tumpuan ke tumpuan). Balok OPS akan diuji dengan metode destruktif, dengan konfigurasi four-point loading, dan protokol pembebanan semi-siklik. Pada tahap eksperimennya, penelitian ini dibantu dengan sistem Digital Image Correlation (DIC), yang dapat mengamati lendutan dan regangan melalui analisis subset foto permukaan sampel. Adapun data pengukuran percepatan balok dengan accelerometer dapat digunakan untuk diolah penulis menjadi rasio redaman dan frekuensi alami yang merupakan karakteristik dinamik balok OPS. Disimpulkan hasil pengamatan karakteristik dinamik sampel menunjukan terjadinya downtrend pada nilai frekuensi alami dan rasio redaman balok setiap selesainya siklus pembebanan, dengan penurunan signifikan hanya terjadi pada nilai rasio redaman balok. Selain itu DIC disimpulkan cukup akurat untuk mengamati lendutan balok.

---

With around 48.42 million tonnes of palm oil production in 2019, Indonesia is the world's largest producer of palm oil. Therefore, the use of oil palm shells as a substitute for coarse aggregate can certainly reduce the waste generated by the palm oil industry. This research will observe the deflection, strain, and natural frequency of a reinforced concrete beam with oil palm shell (OPS) coarse aggregate, measuring 15 x 25 x 300 cm³. The OPS beam will be tested using a destructive method, with a four-point loading configuration, and a semi-cyclic loading protocol. This research was assisted by the Digital Image Correlation (DIC) system, which can observe the deflection and strain through analysis of a subset of sample surface photos both non-destructive and contactless. The measurement of the acceleration of the beam with an accelerometer is carried out to be processed into damping ratio and natural frequency which is the dynamic characteristic of the OPS beam. It was concluded a downtrend happened both on the natural frequency and damping ratio value of the beam after the loading test. The downtrend was more significant on damping ratio rather than on the natural frequency. In addition, DIC was concluded to be quite accurate for observing beam deflection."

"Balok merupakan elemen struktur yang utamanya menahan lentur dan geser dengan atau tanpa gaya aksial atau torsi. Tujuan penelitian ini adalah mengamati perubahan natural frekuensi terhadap pembebanan bertahap pada balok beton bertulang dengan agregat daur ulang. Studi dilakukan secara eksperimen, yakni menggunakan beton dengan agregat kasar daur ulang (kuat tekan fc’ 20,74 MPa). Balok yang digunakan berukuran 3000 × 150 × 250 mm3 yang diberi beban semi-siklik dengan metode pembebanan four-point loading. Pembebanan dilakukan dalam 4 siklus, yaitu siklus 2 ton, 4 ton, 6 ton, dan 8 ton. Respon struktur berupa grafik perpindahan vs beban dan waktu, regangan vs beban diolah dari hasil pengujian menggunakan Digital Image Correlation (DIC) dan pengukuran manual dengan LVDT, dial gauge, dan strain gauge. Karakteristik dinamik balok berupa frekuensi alami dan rasio redaman diperoleh dengan alat accelerometer. Hasil eksperimen tersebut dibandingkan dengan hasil perhitungan teoritis. Analisis menunjukan bahwa balok mencapai batas elastis pada beban 8000 kg. Frekuensi alami cenderung menurun terhadap penambahan beban, hal dikarenakan nilai kekakuan balok yang telah diberi beban akan turun akibat muncul retakan. Nilai rasio redaman pada balok RAC cenderung menurun terhadap penambahan pembebanan bertahap.

---

Beams are structural elements that primarily resist bending and shear with or without axial or torsional forces. The purpose of this study was to observe the natural frequency changes to the gradual loading of reinforced concrete beams with recycled aggregate. The study was conducted experimentally, using concrete with recycled coarse aggregate (compressive strength fc' 20.74 MPa). The beam used is 3000 × 150 × 250 mm3 which is given a semi-cyclic load with a four-point loading method. The loading is carried out in 4 cycles, namely 2 tons, 4 tons, 6 tons, and 8 tons. Structural responses in the form of graphs of displacement vs. load and time, strain vs. load were processed from the test results using Digital Image Correlation (DIC) and manual measurements with LVDT, dial gauge, and strain gauge. The dynamic characteristics of the beam in the form of natural frequencies and damping ratio were obtained by using an accelerometer. The experimental results are compared with the results of theoretical calculations. The analysis shows that the beam reaches its elastic limit at a load of 8000 kg. The natural frequency tends to decrease with increasing load, this is because the stiffness value of the beam that has been given a load will decrease due to cracks appearing. The value of the damping ratio in the RAC beam tends to decrease with the addition of gradual loading."