Browsing by Author "Kariyawasam, KKGKD"

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item: Conference-Full-text
Assessment of the optimum dimensions for cobble-type paving blocks using finite element modeling
(IEEE, 2022-07) Kumarage, NR; Jayasinghe, C; Perera, KPH; Kariyawasam, KKGKD; Herath, S; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
A numerical model was developed to investigate the deflection of permeable interlocking concrete blocks. In this study, the acceptance of paving blocks with extensive plan areas was tested. ABAQUS finite element modeling software which is commercially available was used and a static, linear perturbation analysis was carried out. Three alternative block dimensions were determined according to the guidelines provided in ASTM C936 and were modeled. Mesh sensitivity analysis was carried out on each alternative to identify the optimum global element size for each model. Although all three tested models resulted in vertical deformations less than the threshold, the results indicated a positive association between the exposed plan area and the vertical deformation. Finally, it can be concluded as the SLS 1425 recommended paving block dimensions resulted in the most favorable results.
item: Article-Full-text
Cement stabilized rammed earth as a sustainable construction material
(Elsevier, 2016) Kariyawasam, KKGKD; Jayasinghe, C
In a world where the exploitation of natural resources by the construction industry has become a severe problem, earth can represent an ideal building material that has the potential to reduce the carbon footprint when a cradle to grave life cycle approach is considered. This can also ensure minimum damage to the environment since one day in future, earth obtained can be returned, but could be in a slightly modified form. However, it is very important to consider ways to eliminate the undesirable properties of soil and convert it to a strong and durable building material that would be environmentally friendly. Stabilizing earth with cement and ramming at optimum moisture content forms cement stabilized rammed earth (CSRE), a building material with sufficient strength and durability but low in embodied energy. This paper covers a detailed research carried out on CSRE to establish strength and durability properties together with applications in the form of pilot projects. Sandy laterite soil available in the tropical regions has been identified as a preferable ingredient for CSRE construction which can offer adequate compressive and flexural strengths when cement content is in excess of 6%. Wet strength, erosion resistance and shrinkage properties were assessed and appropriate guidelines are proposed to ensure the durability of CSRE. Further, successful applications of CSRE are highlighted in different forms of construction including housing, roads and retaining walls.
item: Conference-Abstract
Cost effective building systems for rapid construction in tropical climates
Jayasinghe, MTR; Kariyawasam, KKGKD; Jayasinghe, C
Over usage of natural resources for construction of buildings has caused many environmental problems. Hence mainstream requirements of building projects such as cost effectiveness and rapid construction should be achieved while ensuring that the impact on the environment is also minimum. In this context, it is beneficial to use recyclable or renewable materials as building elements. This paper describes a successful adoption of the combination of such systems in a rapid building construction project in Sri Lanka. The building envelope consists of two and three storied steel portal frames, walling system based on compressed straw panels, upper floor with precast concrete slab panels supported on a steel framework, ceiling made from compressed straw panels. The successful application of these systems indicates the possibility to adopt them in the future for rapid, cost effective and sustainable building construction.
item: Conference-Full-text
Estimation of fatigue life of steel masts using finite element modelling
(Department of Civil Engineering, University of Moratuwa, 2015-10) Kariyawasam, KKGKD; Mallikarachchi, HMYC; Hettiarachchi, MTP
Fatigue is an important design consideration for tall steel structures. Accurate prediction of fatigue endurance is essential to design the elements subjected to wind and earthquake induced fatigue. The design guidelines given in codes of practices are applicable only to simple shapes and laboratory experimental verification is costly. Therefore, simulation using finite element software is becoming popular. This paper demonstrates successful coupling of Abaqus/FEA and fe-safe software in predicting the uniaxial and multiaxial fatigue behaviour of steel specimens. The simulated results were verified against experimental results available in literature. The verified simulation technique was used to examine the fatigue life of a64 m tall steel mastlocated on top of a 285m tall tower. Sensitivity of different fatigue inducing properties such as fatigue analysis method, surface finish and plate thickness on fatigue endurance was studied.
item: Conference-Abstract
An integrated framework to select building materials for construction projects in Sri Lanka
(Department of Civil Engineering, University of Moratuwa, 2021-11) Senanayake, HH; Jayasinghe, C; Kariyawasam, KKGKD; Hettiarachchi, P
Construction Industry has contributed to more than one third of global carbon emissions. Adoption of sustainable development approaches could minimize such environmental and social impacts. To guide the construction industry more towards sustainability, one of the key requirements is to develop a standard framework to rate the suitability or greenness of building materials. Such a framework should also address the country-specific priorities and assess whole life performance starting from extraction of raw materials to the disposal of material after usage. This study provides an improved standard framework to rate green building materials that could help policymakers to implement rules, regulations, and tax benefits in near future with the aim of encouraging the use of sustainable building materials. The framework was improved from the existing building material rating system in Sri Lanka by making changes for the fields and measurements and by assigning weightages based on country specific priorities. The developed approach provides a green building material rating for the materials considering the relative importance of seven factors including natural resource consumption, recycled / reused / regenerated component, energy demand and CO2 emission in manufacturing and transportation stages, and indoor environment. This framework was assessed by a case study of five materials, and it was found that the framework provides an integrated solution to measure greenness of building materials. According to the framework developed, highly green-rated materials have the potential to reduce natural resource consumption, enhance energy efficiency and water efficiency, reduce greenhouse gas emissions, enhance indoor environment quality, and improve social well-being. This study shows that some products provide sustainable solutions only in one or two fields and those products are not fully green although the exceptional performance in the one or two fields makes the product attractive to the customers. Moreover, this study found that governing bodies should pay attention to knowledge sharing with not only manufacturing firms but also with rural industries as they tend to lag behind the large firms in producing fully green building materials. The integrated framework developed and tested in this study could be leveraged by the governing bodies, the industry, and the wider world to identify the greenness/sustainability of building materials quantitatively.