Papers by Rangika Halwatura
Reducing CO2 level in the indoor urban built environment: Analysing indoor plants under different light levels
Cleaner Engineering and Technology
Architecture, Jun 22, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
A Preliminary Study on Fabric Formwork for a Mud-concrete Slab System
Mud concrete and fabric formwork are existing technologies in construction industry which are gai... more Mud concrete and fabric formwork are existing technologies in construction industry which are gaining importance with the drive towards a climate conscious construction industry. The current work aims at combining these two technologies toward developing an earthen slab system. A preliminary study was done to assess the viability of fabric formwork for mud-concrete casting and identify potential challenges in developing such a technology. A series of tests were done to identify the performance of commonly available grey fabric ('amu redi') with changing unsupported span lengths of fabric, thickness of overburden mud-concrete layers, and water content of the mud-concrete wet mix. The experimental work verified the viability of using commonly available fabric as formwork for typical mud concrete mixes. The study showed an upper bound on the thickness of the overburden mud concrete layer beyond which the influence on the fabric, measured as the maximum deflection, was negligible as arching effects transfers the loads laterally. A peak water content at which the maximum deflection of the fabric was the highest was observed. In addition, the use of fabric formwork was observed to give a smoother surface finish.
Sri Lankan old buildings are having better indoor comfort relative to the new and remolded buildi... more Sri Lankan old buildings are having better indoor comfort relative to the new and remolded buildings in the world .The main objective is to identify the effective passive techniques and to identify the effective usage. This paper describes the specific passive techniques in Old buildings in Sri Lanka and provides a life cycle cost analysis at the end of research project. Sri Lankan old
Mitigation of safety issues in telecommunication towers
Dynamic, Clay, Secondary Walling for Heat Reduction, in Tropical Indoors
Engineer: Journal of the Institution of Engineers, Sri Lanka
Development of Edible Vertical Gardening System and Societal Impact of Vertical Gardening through a Systematic Literature Review
2020 From Innovation to Impact (FITI)
Creating buildings under the concept of environmental friendliness has become a very common scena... more Creating buildings under the concept of environmental friendliness has become a very common scenario in the current construction industry, due to many concerns in today’s world. Climate change, Global Warming Potential, high carbon emission, and utilization of natural resources are a few of those concerns. Green designs, eco designs, and zero carbon buildings have been developed as some solutions to the above issues. The most common feature in such buildings are green walls, vertical gardens, living walls etc. Adding the above features to green buildings automatically adds value to them in terms of reducing the Urban Heat Island (UHI) effect, reducing Sick Building Syndrome (SBS), controlling indoor air quality, adding a pleasing natural environment and many more. There are many types of vertical gardening systems available in different regions of the world addressing their climatic and other country requirements. In Sri Lanka, the importance of such systems has already been identified, but there is a lack of practical applications. As a solution, an innovative vertical gardening system was started to be developed, which meet the needs of the country. Further, the system was developed to plant various vegetables and herbs, targeting the introduction of the system to the public as an edible gardening system. Evaluating the overall performance of the system based on environmental, social, and economic perspectives from the initial stage of research and development of the prototype is one of the targets. This paper presents the prototype edible vertical gardening system and the results of the systematic literature review conducted in order to analyze the societal impact of the innovative vertical gardening system.
Utilization of Sustainable Timber Materials for Innovative Green Building Solutions
A Preliminary Study on Fabric Formwork for a Mud-concrete Slab System
2020 Moratuwa Engineering Research Conference (MERCon), 2020
Mud concrete and fabric formwork are existing technologies in construction industry which are gai... more Mud concrete and fabric formwork are existing technologies in construction industry which are gaining importance with the drive towards a climate conscious construction industry. The current work aims at combining these two technologies toward developing an earthen slab system. A preliminary study was done to assess the viability of fabric formwork for mud-concrete casting and identify potential challenges in developing such a technology. A series of tests were done to identify the performance of commonly available grey fabric ('amu redi') with changing unsupported span lengths of fabric, thickness of overburden mud-concrete layers, and water content of the mud-concrete wet mix. The experimental work verified the viability of using commonly available fabric as formwork for typical mud concrete mixes. The study showed an upper bound on the thickness of the overburden mud concrete layer beyond which the influence on the fabric, measured as the maximum deflection, was negligible as arching effects transfers the loads laterally. A peak water content at which the maximum deflection of the fabric was the highest was observed. In addition, the use of fabric formwork was observed to give a smoother surface finish.
Impact of Internal and External Factors In Buiding Energy Consumption Under Tropical Climatic Condition
Possible Cellular Structural and Chemical Changes of Timber Under Water
Decoding the societal transitions on environmental innovation under vernacular timber construction practice in Sri lanka
2019 From Innovation to Impact (FITI), 2019
In an economy, innovation is well-thought-out as one of the important factors for development, gr... more In an economy, innovation is well-thought-out as one of the important factors for development, growth and competitiveness of a country. Environmental innovations defined as a modified processes, practices, systems and products profit the environment and contribute to environmental sustainability during its entire lifecycle. Vernacular timber construction practice in Sri Lanka is dealt with environmental innovations. Constructions were made based on the needs of the inhabitants with the available resources in the particular context. Societal transitions are highly complex processes that unfold over time-spans of decades as they overcome challenges in an experienced process. This study aims to conduct a field survey and collect maximum timber samples; to decode and emphasize the worth of the existing information. Heritage timber structures are perfect living samples comprehending a preserved living proof of material utilization survived in a tropical climate. As a preliminary step for an investigation, a microscopic observation was conducted. To further analysis Energy Dispersive X-Ray Spectroscopy; a chemical microanalysis technique was used in conjunction with scanning electron microscopy (SEM). Survey results and analytical examinations conveyed knowledge which is not yet decoded who had experienced in vernacular timber construction practice. But still there should be useful ideas to be taken from their solutions. Therefore, results discuss the necessity of decoding and scientifically proving the value of the existing vernacular practice in Sri Lanka that leads to another environmental innovation in future that navigate on societal transitions through evidenced knowledge.
Proceedings of International Forestry and Environment Symposium, 2018
Urbanised areas are tend to heat up more than neighborhoods as consequences of global warming and... more Urbanised areas are tend to heat up more than neighborhoods as consequences of global warming and urban heat island effect due to high built up areas. Moreover, buildings are the most energy consumptive assets in energy systems. Green roofing is a popular strategy for passive cooling of buildings in present green building industry and it has become the best solution to overcome problems related to thermal comfort. A conventional green roof made up with the combination of vegetation layer, growing media, drainage layer and root barrier layer add a huge weight up on the existing roofs. Hence, green roof modular system is more efficient in cost and performances basis with less weight as separated by prefabricated or non−prefabricated novel method. This study evaluated the effect of fixed green roof modular system to an existing building to ensure the thermal comfort performances of outdoor and indoor conditions of the building by innovating portable frame network and new growing media for green modules with low weight, low cost and easy maintenance. Developed module's unit weight was 400 −450 g and it covered an area of 412.5 cm 2. It was fabricated with fiber glass and a frame network was developed using canvas−rubber mixed materials with a unit weight of 622.5 g. Growth medium was prepared by using rubber and coir mixed material. Ipomea aquatica, Centella asiatica and Alternanthera sessilis were used as testing vegetation for the developed green roof modules. Leaf area (LA) and number of leaves were used as the parameters to select the best plant variety for the green roof. Subsequent thermal performance parameters of the green roof were analysed by comparing it with a normal roof of the same building. Leaf area of C. asiatica was significantly higher than I. aquatica and A. sessilis. Plant height, LA and number of leaves are the main factors that control the penetration of solar radiation; hence it influences the temperature. By considering statistical analysis and above facts, C. asiatica was selected as the best plant variety for the modules. A maximum indoor and outdoor temperature difference was reported after implementing the green roof modular system as 3 C. Control roof showed a maximum temperature difference of 2.3 C between indoor and outdoor. The maximum relative humidity difference between inside and the outside roof was recorded as 3.5% while control roof was given 3.3%.Therefore green roof modular system developed with fiberglass and frame network with coir-rubber mixed growing media for Centella asiatica can be suggested to enhance the thermal comfort of indoor and outdoor environments.
Problem-Based Learning (PBL) in Engineering Education in Sri Lanka: A Moodle Based Approach
Advances in Intelligent Systems and Computing, 2020
When trees are planted too close to a building, the roots of them are causing damages to that bui... more 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.
Due to heavy industrialization that took place after the Industrial Revolution, per capita energy... more Due to heavy industrialization that took place after the Industrial Revolution, per capita energy consumption in the world has risen exponentially, depleting the planet’s limited energy deposits. As a result of most the modern technologies, unfavourable conditions on the environment are created. So, there is an urgent requirement to move towards the methods, which minimize the energy demand. Electricity demand in Sri Lanka is higher than its production and the usage of Air Conditioning is increasing day by day. Therefore, straw bale was identified as a feasible substitute to be used in addressing the increasing demand for A/C due to many reasons such as low initial cost, low conductivity and durability. Hence, studying on the long term performance of straw bale construction will be highly essential. On this regard, actual measurements were taken and were used to validate the computer simulations for straw bales and other walling materials to get the A/C demands for different cases. ...
Energy represents a considerably higher percentage of running cost of a building and also affects... more Energy represents a considerably higher percentage of running cost of a building and also affects the optical and thermal comfort of the occupants. Despite the fact that the investment for buildings is higher than most of those equipment, only developed countries and few developing countries have developed their own energy ratings or certifications for buildings. Nevertheless, energy efficiency in building sector is utmost important as it accounts more than one fifth of annual energy consumption worldwide. Energy efficiency rating system can be considered as a key policy instrument that will assist government to reduce the energy consumption. Energy rating includes the direct benefits such as, energy requirement and CO2 emission reduction; increase the public awareness regarding energy issues; cost reduction for the users and improve the available data for the building. Studying the existing energy rating systems is very much important prior to the development of energy rating system for Sri Lanka. This paper examines 12 existing energy rating systems and analyses the adaptation opportunities for emerging Sri Lankan energy labelling system. The existing rating methodologies including asset and operational rating, parameters used for developing the energy rating and the comparability matrix were compared and discussed in this review.
Beneficiary participation is an important factor for donor funded projects. Since it gives many b... more Beneficiary participation is an important factor for donor funded projects. Since it gives many benefits and final product to the community, donors are always insisting the projects with beneficiary participation. However, for smooth execution of beneficiary participatory projects has to cross many hurdles for its successful completion. Identify those drawbacks and addressing them is necessary. The Raw data are collected through a questionnaire and analyse those according to the existing data from the donor funded executed project. The results show that there are many factors that affect the successful completion of beneficiary participatory projects. The findings have emphasis on more site visits by the management staff, budget to be suit to the site location and the conditions. Findings has extended to management staff travelling distances, vehicle allocations to staffs, payment procedure, meeting minutes to be distribute on time to site and also recommending to some team building...
Identifying consumer perceived value of tourism product
Optimization of Thermal Comfort in Sri Lankan Residential Buildings
2018 Moratuwa Engineering Research Conference (MERCon), 2018
The aim of this study is to evaluate the thermal comfort state in residential buildings in Sri La... more The aim of this study is to evaluate the thermal comfort state in residential buildings in Sri Lanka and to study the possibility of getting them into the comfort zone without air conditioning. Located near the equator, Sri Lanka has a tropical climate with high temperature and relative humidity level. Therefore, the need of having a thermally comfortable living environment is a must in these conditions. A case study approach has been made in this study to evaluate the research problem. The selected 14 case study houses were optimized using Design-Builder, energy simulation software. The evaluation results highlight that the comfort level of the houses can be improved using mud concrete blocks as the external wall material and clay tiles as roofing. The optimisation results further indicate that thermal comfort level of the residential buildings in Sri Lanka can be achieved without using air conditioning if designed properly
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Papers by Rangika Halwatura