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

摘要

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.