Pengaruh perendaman panas dalam larutan boraks 5 persen dan variasi pola sambungan terhadap perilaku lentur balok galar bambu wulung

NUGROHO, WD. Hary, Ir. Morisco, Ph.D

2004 | Tesis | S2 Teknik Sipil

Kayu baru layak tebang setelah mencapai usia setidaknya 30 tahun. ya masa tumbuh ini serta adanya peningkatan kebutuhan akan kayu Laman menyebabkan cadangan kayu di alam semakin berkurang. Balok galar atau balok glulam bambu - yaitu laminated beam yang dibuat dari galar (lembaran serat bambu) dan resin sintetik Urea Formaldehida (resin UF) sebagai resin perekat - dapat menjadi altematif untuk mensubstitusi dan mereduksi penggunaan kayu keras alami dalam lingkup pekerjaan teknik sipil. Penelitian ini bertujuan untuk mengetahui pengaruh rendaman panas dalam larutan boraks 5% dan variasi pola sambungan terhadap kekuatan balok glulam bambu Wulung akibat pembebanan lentur. Pengujian pendahuluan - berdasarkan Standar ISO 1976 dengan penyesuaian pada bentuk specimen - dilakukan untuk mengetahui pengaruh perendaman panas dalam larutan boraks 5% terhadap sifat fisika dan mekanika bambu Wulung. Benda uji lentur balok glulam bambu Wulung terdiri dari 24 specimen dengan dimensi 38 mm x 95 mm x 2000 mm. Antar lapisan galar direkatkan dengan resin UF (UA-104) sejumlah 60# MDGL pada tekanan kempa dingin 1,5 sampai 2 MPa selama sekurang-kurangnya 4 jam. Beban lentur statik kemudian diberikan secara bertahap pada belok uji sampai mengalami keruntuhan. Pengujian lentur terhadap balok glulam bambu Wulung menunjukkan bahwa perebusan berpengaruh terhadap peningkatan kuat lentur balok dalam menahan lentur. Kuat batas terbesar (rata-rata 7708,63 N atau 157,89% dari kuat batas teoritisnya dicapai oleh balok rebus tanpa sambungan, BR-1; disusul oleh balok rebus dengan sambungan pola-X, BR-3 (rata-rata 700,85 N atau 143,43% dari kuat batas teoritisnya). Saat kuat batas itu tercapai, terjadi lendutan sebesar rata-rata 29,9 mm untuk BR-1 dan 28,32 mm untuk BR-3. Lendutan balok glulam bambu Wulung cenderung lebih besar daripada lendutan izin balok kayu biasa.

Trees are suitable for end use when at least harvested at 30 years old. This owth duration and also the huge of wood demand cause the wood stock in long gr nature more and more decreasing. Galar beam or glulam bamboo beam - that is laminated beam made from galar (sheet of bamboo fiber) and synthetic resin of Urea Pormaldehyde (UP-resin) as glue matrix - can become the alternative for substituting and reducing the natural solid wood consumption in civil engineering works. This research was aimed to reveal the influence of hot immersion treatment in 5% borax and variation of joint pattern to the strength of galar beam under bending load. Preliminary examination - according to ISO 1976 Standard with the adjustment of specimen form - conducted to know the influence of hot immersion treatment in 5% borax on the physical and the mechanical behavior of Wulung bamboo, and to know the shear strength of UP-resin bonded Wulung bamboo. Bending specimens of glulam bamboo beam consisted of 24 specimens with 38 mm x 95 mm x 2000 mm dimension. Glue spread 60# MDGL used for adhesion between galar laminates, cured with cold pressing by 1.5 until 2 MPa during four (4) hours or more pressing time. A statically bending load pressured step by step to each of the specimen until failure. Bending examination of glulam Wulung bamboo beam showed that hot immersion had a positive effect to the bearing capacity of the beam. Largest strength limit produced by boiled beam with no joint, BR-1 (average 7708.63 N of 157.89% from its theoretical strength). This value was closely followed by boiled beam with type-X joint, BR-3 (average 7002.85 N or 143.43% from its theoretical strength). At the time when limit strength reached, 26.9 mm slope (for BR1-R) and 28.3 mm slope (for BR3-R) occurred. Glulam Wulung bamboo beam tend to bend greater than approved bending ordinary wood beam.

Kata Kunci : Balok Galar Bambu Wulung,Perilaku Lentur Perendaman Panas,Boraks 5 Persen, galar beam, glulam bamboo beam, bending behavior, hot immersion, extension pattern