Behaviour of Post-Tensioned Kempas Timber Beam with Two Tendon Types

The post-tensioning technology is commonly used for concrete structures especially bridges. This technology is applied for timber elements in many countries effectively. In Malaysia the timber post-tensioning still not known yet. This research aim to propose the post-tensioning technique for timber beams. The timber type is Malaysian Kempas and the device used to apply the post-tensioning force is hydraulic jack. Three types of specimens were tested using the bending test (four-point bending test) for a simple support beam. two type of specimens are post-tensioned timber beams with black threaded rod bar (PTBR) and post-tensioned timber beams with silver threaded rod bar (PTSR). All the specimens' length is 1.2meter and the dimension of timber is 90mm x 40mm. The increment of moment capacity of post-tension timber beam compared to the timber beam the moment resistance increment is 1.42 times. The moment resistance of the post-tensioned timber beam had average increment is 27.4% - 31.8%. The other finding is the failure mode of specimens it is changed from brittle tension failure to ductile failure (compression failure) the cause of this behavior is the role of the post-tensioning rods.