Browsing by Author "Somarathna, HMCC"

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item: Conference-Full-text
Analysis of Strain Rate Dependent Tensile Behaviour of Polyurethanes
(2016-01-06) Somarathna, HMCC; Raman, SN; Badri, KH; Mutalib, AA
The stress-strain behaviour of elastomeric polymers, such as polyurethane (PU), exhibit high rate dependency, stress–strain non-linearity, and high pressure dependency when compared to other construction materials. Since these polymers exhibit the potential to be applied as retrofitting and protective material for various types of structural materials, in enhancing their load-carrying capacity, ductility and structural survivability under different loading regimes, it is essential to comprehensively investigate their mechanical behaviour at varying strain rates. This study was undertaken to investigate the tensile stress-strain characteristics of elastomeric PU at varying strain rates, ranging from 0.001 s-1 to 0.1 s-1 (low to intermediate). The primary emphasis of this study was on the strain rate sensitivity of the tensile properties, including the Young’s modulus, tangent modulus, ultimate tensile stress, fracture strain, and strain energy modulus. The findings indicated that stress-strain behaviour of the PU exhibited high dependence to variations in strain rates and stress–strain non-linearity. The behaviour of PU also provided good concurrence with recent studies, which explored the strain rate dependency of other elastomeric polymers.
item: Conference-Full-text
Feasibility study on a mud block with straw
(2013-11-11) Somarathna, HMCC; Sampath, KAC; Jayathilaka, KG; Ranasinghe, AWLH; Halwatura, RU; Perera, AADAJ
When, trying to establish “Sustainability” within local built environment, it is important to understand prevailing methods that are using. As a result, concentrating on “methods of wall construction”, it was found that, “mud”, was used over many centuries in traditional architecture. Therefore, concentrating on “mud wall construction”, the goal was set to be developed, a “mud block”, which has more structural durability, less weight, low cost, together with high performance with respect to indoor air quality. However, as an initial attempt of the ultimate invent of “mud block”, this research was carried out to analyse, the correct proportions to invent such block. During the research mainly two types of mud blocks were casted; partially compacted mud block and poured mud block. During the casting process soil, cement, straw were mixed with water in different proportions to understand the best particle mix for the proposed block and compared the compressive strengths of each sample. From the analysis it was found that, there is a high possibility of inventing a effective mud block which has required strength for a load bearing dwellings, while minimizing the structural cast with less weight and low cost with simple manufacturing process.
item: Conference-Full-text
Identification of damages to building structures due to roots of trees
(2013-11-11) Halwatura, RU; Jayawardena, VGNP; Somarathna, HMCC
When trees are planted too close to a building, the roots of them are causing damages to that building in both direct and indirect ways. In many cases, these subterranean problems go unnoticed, until cracks appear on surfaces. The remedial works for such cases can be always difficult and expensive. This research was carried out to identify the causes and effects of not using the safe planting distances and then it is extended with a detail survey to find safe distances using 5 categories of trees, which are most common in Sri Lanka. It was noted that the direct damages to civil structures are very common here in Sri Lanka. It was observed that the damage from Bodhi tree is much greater than other trees. Therefore, its’ safe planting distance is around 11 metres. Safe planting distances for Tamarind and Royal Poinciana are in a range between 6 to 7 metres. For Jack & Mango tree, it is about 4 to 5 metres. So these safe planting distances has presented numerically in this report.