Karakteristik Balok Laminasi (Glulam) Kayu Ekaliptus (Eucalyptus urophylla ST. Blake)

Abstract

The use of wood for structural purposes requires a large dimension and long span as well as specific requirements of high strength. On the other hand, a lot of wood available today is wood from plantations with fast growing species of small diameter and generally have inferior properties such as defects content, natural durability and strength compared to wood from natural forests. One common way to get the wood to the desired dimension is the lamination technique. One of the laminate product used as a structural material is laminated timber. The aim of the study was glulam composed by three laminas thickness from eucalyptus wood. Three laminas 1cm, 1.5cm, 2cm thickness, were prepared in this study. Each laminae was tested by non destructive evaluation of deflection method to determine Modulusof Elasticity (MOE). The highest MOE of laminae was placed at the outside of glulam, then between laminas were glued by isocyanate resin. The dimension of glulam was (8 x 6 x 110) cm in thick, width, and length. The physical and mechanical properties of glulam were evaluated refering to standard JAS 234:2003. The physical properties of glulam timber of moisture content was in average value of 13.37%. The density mean of glulam timber were 0,65g/cm³ to glulam A composed by 1cm thickness of laminae, 0,63g/cm³ to glulam B composed by 1.5cm thickness of laminae, 0,56g/cm³ to glulam C composed by 2cm thickness of laminae. Delamination properties of hot and cold water were 25.2% and 4.99% for glulam A, 45.9% and 8.03% for glulam B, 73.86% and 0% for glulam C. The average value of mechanical properties Modulus of Elasticity (MOE) were 10.06x10⁴ kgf/cm² for glulam A, 7.42x10⁴ kgf/cm² for glulam B, and 5.63x10⁴ kgf/cm² for glulam C. The Modulus of Rupture (MOR) of glulam beams were 561 kgf/cm², 424 kgf/cm², and 327 kgf/cm² for glulam A, glulam B, and glulam C, respectively. Average value of shear strength properties were 98.42 kg/cm² for glulam A, 90.23 kg/cm² for glulam B, 79.01 kg/cm² for glulam C. Moisture content and delamination on cold water glulam timber were in compliance with JAS standards 234: 2003 while the delamination on heat water not fullfill to meet the standards. The MOE and MOR values the glulam timber (except MOE laminated timber with a thickness of 1.5 cm and 2 cm) were in compliance with JAS standards 234: 2003.