Pengaruh jenis perekat terhadap keruntuhan lentur dan geser balok laminasi galar serta bilah vertikal bambu petung

GUNAWAN, Purnawan, Dr.Ir. Fitri Mardjono, M.Sc

2006 | Tesis | S2 Teknik Sipil

Teknologi perekatan dalam kaitannya dengan teknik laminasi adalah proses penggabungan bahan yang berdimensi kecil dan terbatas menjadi bahan yang berdimensi lebih besar baik panjang, lebar dan tebal. Perekat sintetik komersial di Indonesia yang sering digunakan untuk pekerjaan perekatan kayu adalah urea formaldehyde (UF-104) dan melamine formaldehyde (MF-204). Laminasi bambu memiliki kelemahan terhadap faktor kuat lentur dan gaya geser. Penelitian ini mempelajari mengenai pengaruh jenis perekat, elemen pembentuk balok laminasi bambu petung dalam kondisi kegagalan lentur dan geser. Uji pendahuluan dilakukan untuk mengetahui sifat fisika dan mekanika bambu dengan menggunakan standar ISO 3129-1975. Dua macam pengujian dilakukan yaitu berupa uji lentur dan uji geser. Balok laminasi galar terdiri dari 13 lapisan sedangkan balom bilah tersusun atas hampir 65 buah bilah dalam 5 lapisan laminasi. Kedua jenis perekat ini digunakan melalui proses pengempaan dingin untuk merekatkan balok-baiok dengan posisi lapisan laminasi verkikal tersebut. Besarnya pengempaan adalah 2,5 MPa dengan menggunakan hydraulics jack. Pengujian dilakukan dengan menggunakan four points load system.

Bonding technology in the term of lamination technique is the technique of merging small material with limited sizes into material that bigger, longer, wider and thicker dimension. Synthetic commercially glues in Indonesia, that commonly being use in the wood bonding process are urea formaldehyde and melamine formaldehyde. The natural weaknesses of laminated bamboo beam are bending and shear failure. The objectivities of this research are to observe the influence glue type and the element of laminated beam of bamboo petung in bending and shear rupture. Preliminary test had been conducted to know more about the physical and mechanical behavior with ISO 3129-1975 standard. Two kind of test had been carried out on both stripped and flatted laminated bamboo. They were bending and shear tests. Flatted beam was being arranged by 13 layers of flatted bamboo, while stripped one had been made by almost 65 stripped bamboo that been arranged into 5 lamination layers. Cold pressure process of urea and melamine were being used on these vertically layers of laminated beam. Hydraulics jack had been used to make 2.5 MPa pressure. Four points statically load system was applied on both bending and shear tests. From the preliminary test on bamboo from Magelang noted that the moisture content and the density were 12.48% and 0.98 g/cm3. The mechanical behavior indicated the compression parallel and perpendicular, tensile, modulus of rupture, modulus of elasticity, shear strength were 62.53 MPa, 14.54 MPa, 203.374 MPa, I62.34 MPa, 13589 MPa and 9.18 MPa. Nevertheless, from the preliminary test on bamboo .from Wates indicated that the moisture content and the density were 23.75% and 0.702 g/cm3 while the mechanical behavior showed 44.468 MPa, 13.407 MPa, 157.065 MPa, 117.39 MPa, 18209 MPa and 10.20 MPa on similar parameters above. According to LPMB-PKKI-1996 bamboo was classified into class II wood thus if bamboo was being assumed as same as wood. From the result of moment, stiffness and Modulus of Rupture (MOR) parameters in bending and shear tests, concluded that the strength stripped laminated beam was higher than flatted laminated one. Globally the used of urea on laminated beam was stronger than melamine, but specifically for stripped lamination in bending test gave reverse conclusion.

Kata Kunci : Balok Laminasi Bambu,Bambu Petung,Kegagalan Lentur dan Geser, bamboo petung, bending and shear rupture, gluelam