Mechanical properties of structural bamboo following immersion in water

Bamboo is widely used as scaffolding for which collapses, often associated with rain events, are not uncommon. The presented study quantifies the degradation of mechanical properties of bamboo samples following immersion in water for 1 and 7 days to simulate the effects of significant rain events. Compression, longitudinal shear and splitting tests were conducted to obtain the respective strengths and moduli. The mechanical properties were observed to degrade significantly with increased moisture content (MC) up to about MC = 30%, a value close to the expected fiber saturation point (FSP). Beyond MC = 30%, further degradation, while apparent, was less significant. Immersion in water for one day was observed to be sufficient to achieve the FSP; under these conditions, compressive strength was observed to be 75% of that obtained from tests conducted at a standard 'air-dry' MC = 12%. Accompanying the reduction in strength with increased MC, the bamboo was observed to transition from a relatively brittle behavior to a very ductile behavior. For scaffold applications, degradation of compression capacity is not only critical but also shown to be a conservative indicator for other mechanical properties.