Abstract:
Bamboo is a woody grass belonging to the sub family Bambusoideae of the family
Poaceae (Gramineae). The increasing need for sustainable building construction and the
use of natural local materials have made bamboo a popular material. Sri Lanka is an island
nation located south of the Indian peninsula. It is a tropical country with distinct dry and
wet seasons. Sri Lanka has nearly 5000 ha of natural bamboo forests and another 5000 ha
of domestically cultivated land, scattered mainly in the South Western zone which
amounts to 0.5% of the total forest cover in Sri Lanka. However, with the restoration of
cascading reservoir systems in the Eastern Province, there is potential to have many
marginal lands converted to bamboo plantations hence allowing for the growth and
harvesting of bamboo in a sustainable manner for use in construction as a structural
material.
Sri Lanka is home to ten endemic species of bamboo. In addition, several exotic species
have been introduced to the country. The bamboo plant has a variety of uses. Industrial
utilization of bamboo can be through primary or secondary value addition, which
enhances the market value of bamboo. Bamboo in construction is found in either full-culm
or engineered form. Bamboo is limited in its application through its durability and its
tendency to split. Hence it needs to be processed and treated to ensure its long-term usage.
Bamboo structures should be detailed appropriately for the full protection of treated
bamboo. Bamboo used for construction has to undergo harvesting, grading, cleaning,
preservative treatment, and storage. Determination of structural parameters of Sri Lankan
bamboo could be based on ISO standards since other standards are often based on ISO
standards themselves and are more suitable for bamboo species from those particular
countries of those respective standards. To date, the mechanical characterization of Sri
Lankan bamboo species has not been found in literature.
The widespread availability of Bambusa Vulgaris (Sri Lankan Yellow bamboo) led to it
being chosen for investigation in this study. All bamboo culm sections in this study were
obtained from a single supplier with initial moisture content and dimensions obtained on
delivery. Once culm data was measured for all culms, a random selection of culms
underwent preservation treatment prior to testing.
The mechanical characterization tests provided a set of structural parameters including;
average strength values in compression, shear, flat ring flexure and tension for Bambusa
Vulgaris (Sri Lankan Yellow bamboo). All Strength values tend to show gradual increase
from bottom towards the top of the culm. Comparison of treated vs. untreated strength
values across all four tests showed no significant increase in strength initially due to
preservation treatment. Average densities of test samples tend to show a strong
relationship with their respective strengths, whereas average diameter does not.
Comparison of average strength values of Bambusa Vulgaris (Sri Lankan Yellow
bamboo) with the same species from Kenya as well as relatable other species from
Thailand revealed that the average strength values of Bambusa Vulgaris (Sri Lankan
Yellow bamboo) to be lower compared to the respective average strength values of other
species except in the case of tensile strength. Sri Lankan Bambusa Vulgaris showed
characteristic strengths of 17.0N/mm
2
, 2.0N/mm
2
, 16.0N/mm
2
and 20.0N/mm
for
compressive strength, shear strength, bending strength in flat ring flexure and tensile
strength respectively.
Citation:
Vipushnan, R. (2021). Structural testing and characterization of Sri Lankan yellow bamboo Bambusa vulgaris [Master's theses, University of Moratuwa]. Institutional Repository University of Moratuwa. http://dl.lib.uom.lk/handle/123/22545