Bamboo Taper Effect on Center Point Bending Test

Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually have unique shape. Its geometrical shape assumed as tapered hollow pipe. This study aims to find the effect of bamboo taper to its strength properties on center point bending test. The ratio between the Modulus of Rupture (SR) calculated in the center point, and the maximum bending stress along the beam is called strength ratio of taper (Ct). The theoretical calculation results Ct value is 1 if the taper lower than 0.023, while Ct value become lower if the taper is higher than 0.023. The survey on Ampel (Bambusa vulgaris Schrad.), Tali (Gigantochloa apus (Bl. Ex Schult. f) Kurz), Gombong (Gigantochloa verticillata (Willd.) Munro), and Mayan (Gigantochloa robusta Kurz.) found that the overall taper range is -0.0047-0.0088 and 0-0.0127 for inner and outer taper respectively. On that overall range the Ct value is always 1, so it is reasonable to ignore the taper effect on one point bending test.