Institutional-Repository, University of Moratuwa
Welcome to the University of Moratuwa Digital Repository, which houses postgraduate theses and dissertations, research articles presented at conferences by faculties and departments, university-published journal articles and research publications authored by academic staff. This online repository stores, preserves and distributes the University's scholarly work. This service allows University members to share their research with a larger audience.
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Recent Submissions
item: Thesis-Full-text
Development of a web application through a mobilized crowdsourcing platform to enable participatory risk sensitive urban development
(2025) Kangana, KMND; De Silva, C; Kankanamge, N
Flooding remains the most frequent and destructive natural disaster in Sri Lanka, exacerbated by rapid urbanization and evolving precipitation patterns, leading to extensive socio-economic damage. Despite the availability of technological tools for disaster management, community engagement in early warning systems and risk mitigation remains minimal. This study addresses this gap by developing an integrated platform comprising a crowdsourcing-based mobile application and a web-based geospatial decision support system, aimed at fostering participatory risk-sensitive urban development. The mobile application enables real-time flood data collection from affected communities, while the web platform visualizes and validates this data, providing actionable insights for disaster response authorities. A flood vulnerability assessment model was developed using 30 years of historical flood data, nine key conditioning factors—including topography, weather patterns, hydrology, land cover, and soil type—and Sentinel-2 satellite imagery to enhance prediction accuracy. The methodological approach integrates machine learning techniques for crowdsourced data verification, participatory workshops for system validation, and mobilization strategies for community engagement. The research makes significant contributions to both theory and practice. Theoretically, it advances the discourse on participatory disaster management by integrating community-based crowdsourcing with remote sensing analytics. The study also refines geospatial modelling techniques for flood vulnerability assessment, incorporating novel indicators such as Night-Time Light (NTL) data to measure human exposure to flooding. In practice, the developed platform enhances disaster preparedness by providing a scalable, cost-effective solution for real-time flood risk assessment. The findings demonstrate that combining crowdsourced data with remote sensing can bridge critical information gaps in disaster management, empowering communities and authorities to respond proactively to flood hazards. The study's framework can be adapted to other flood-prone regions, contributing to global efforts in urban resilience and risk-sensitive development.
item: Thesis-Full-text
Development of a mobile augmented reality application to enhance youth engagement in designing public spaces
(2025) Ranasinghe, RADM; De Silva, C; Kankanamge, N
Ethical considerations are integral to the work of entrepreneurial engineers, whose innovations and decisions frequently carry significant societal implications. This study explores how Sri Lankan entrepreneurial engineers as a group of technology entrepreneurs adhere to engineering ethics, the challenges they face, and the strategies they employ to uphold ethical principles in their techno-entrepreneurial ventures. Addressing a significant gap in the literature, the research employs a constructivist grounded-theory methodology, drawing on face-to-face interviews with a purposive and theoretically selected sample of 22 entrepreneurial engineers. The findings reveal that most entrepreneurial engineers perceive engineering ethics as a "guideline" for ethical business practices, navigating a business environment populated by stakeholders and competitors characterized as "ethical-unethical colleagues." They also encounter an "avaricious society" that presents numerous ethical challenges during their entrepreneurial journeys. To adhere to engineering ethics, the participants adopt a tripartite strategy involving internalization, employee engagement, and public outreach. The consequences of these practices include "lasting benefits" and "short- term losses," ultimately contributing to the "enduring prosperity" of their firms. This study introduces the substantive theory called “theory of enduring prosperity”, illustrating how adherence to engineering ethics fosters long-term business sustainability in the Sri Lankan context. The findings suggest that entrepreneurial engineers should prioritize ethical practices from the startup stage, as these lead to sustainable growth, even if they encounter temporary setbacks in a challenging societal environment. This study makes a holistic contribution to the existing literature by underscoring the importance of engineering ethics in entrepreneurial success. However, limitations such as gender bias and reliance on the perspectives of entrepreneurial engineers are noted. Future research could address these limitations and explore how entrepreneurial engineers can contribute to achieving sustainable development goals through the application of engineering ethics.
item: Thesis-Full-text
Engineering ethics & entrepreneurship : a grounded theory based study among entrepreneurial engineers in Sri Lanka
(2025) Wijesinghe, DPS; Jayawardane, VPT; Dasanayake, SWSB
Ethical considerations are integral to the work of entrepreneurial engineers, whose innovations and decisions frequently carry significant societal implications. This study explores how Sri Lankan entrepreneurial engineers as a group of technology entrepreneurs adhere to engineering ethics, the challenges they face, and the strategies they employ to uphold ethical principles in their techno-entrepreneurial ventures. Addressing a significant gap in the literature, the research employs a constructivist grounded-theory methodology, drawing on face-to-face interviews with a purposive and theoretically selected sample of 22 entrepreneurial engineers. The findings reveal that most entrepreneurial engineers perceive engineering ethics as a "guideline" for ethical business practices, navigating a business environment populated by stakeholders and competitors characterized as "ethical-unethical colleagues." They also encounter an "avaricious society" that presents numerous ethical challenges during their entrepreneurial journeys. To adhere to engineering ethics, the participants adopt a tripartite strategy involving internalization, employee engagement, and public outreach. The consequences of these practices include "lasting benefits" and "short- term losses," ultimately contributing to the "enduring prosperity" of their firms. This study introduces the substantive theory called “theory of enduring prosperity”, illustrating how adherence to engineering ethics fosters long-term business sustainability in the Sri Lankan context. The findings suggest that entrepreneurial engineers should prioritize ethical practices from the startup stage, as these lead to sustainable growth, even if they encounter temporary setbacks in a challenging societal environment. This study makes a holistic contribution to the existing literature by underscoring the importance of engineering ethics in entrepreneurial success. However, limitations such as gender bias and reliance on the perspectives of entrepreneurial engineers are noted. Future research could address these limitations and explore how entrepreneurial engineers can contribute to achieving sustainable development goals through the application of engineering ethics.
item: Thesis-Abstract
Ultimate shear resistance of rock-sockets in the presence of bentonite filter cake
(2025) Bulathsinhala, AUVB; Puswewala, UGA; Wanniarachchige, PK
In various global regions, and notably in Sri Lanka, Bentonite slurry serves as a prominent drilling fluid and an indispensable agent in the realm of pile and diaphragm wall construction activities. The use of Bentonite slurry in these applications is based on its inherent characteristics as a Bingham fluid, replete with thixotropic properties, which imparts a support for stability enhancement within the bore hole during the intricate phases of drilling, washing, and concreting. Notably, it creates a vital barricade against side wall collapse, thereby safeguarding the structural integrity of the construction site. Moreover, Bentonite serves a dual role, not only as a structural support but also as a versatile coolant and lubricant for drilling tools, ensuring the precision and efficiency of the excavation process. However, despite the numerous advantages conferred by Bentonite slurry in facilitating the pile construction process, some research has identified adverse effects that impact pile performance. This contrast of favourable and unfavourable effects highlights the complex interplay between the unique rheological properties of Bentonite slurry, demanding further investigation to optimize its use in construction activities.
Several researchers actively involved in the oil and construction industries have undertaken extensive investigations into the Bentonite Filter cake (BFC) formation over soil and rock surfaces, as well as its consequences on the performance of piles. However, a substantial proportion of these investigations has been on the development and consequences of filter cakes over sedimentary rocks, including mudstones, siltstones, and sandstones, which are abundant in e.g. North American and Australian regions. These sedimentary rock formations have comparatively higher permeability when contrasted with crystalline rock types. The enhanced permeability of sedimentary rocks facilitates the BFC formation over their surfaces to a greater extent, thereby introducing a unique set of challenges to geotechnical engineering.
The presence of BFCs on the surfaces of sedimentary rocks produces adverse effects, particularly concerning the capacity of rock sockets to provide skin friction. Consequently, construction practices in these geological contexts necessitate the incorporation of higher safety factors to account for the inherent uncertainties that may arise due to the presence of these distinctive infill layers. These uncertainties and associated challenges require a thorough and context-specific approach to pile design and construction in regions of sedimentary rock formations, highlighting the importance of comprehensive research in mitigating potential performance issues and ensuring the structural integrity and safety of construction projects.
Countries like Sri Lanka have used the same conventional pile design practices which are used in other regions, even though it leads to a certain degree of design conservatism. This conservative approach prevails even in the face of the abundant presence of crystalline Metamorphic rocks characterized by higher strength capacities and exceptionally low permeability characteristics. The inherent geotechnical properties of these crystalline Metamorphic rocks, which hinder the formation of BFCs in comparison to sedimentary rock types, warrant a re-evaluation of the prevailing design practices.
Hence, this thesis presents a comprehensive investigation of rock socketed pile design beginning with an examination of Bentonite Filter Cake (BFC) formation over metamorphic rocks. Four distinct metamorphic rock types characterized by their major mineral compositions were collected: Biotite gneiss, Quartzofeldspathic gneiss, Garnet granulite gneiss, and Charnockitic gneiss. These samples were taken to represent three distinct weathering grades: fresh, slightly weathered, and moderately weathered. In order to investigate the formation of BFC over metamorphic rocks, a pressure chamber was constructed to apply a Bentonite slurry pressure of 0.3 MPa over a period of 12 hours, based on data collected via a questionnaire survey providing the basis for the pressure and its duration. The findings revealed that BFC thicknesses averaged 2 mm on fresh metamorphic rocks and 4 mm on moderately weathered rocks. Among the rock types, Garnet granulite gneiss demonstrated the highest BFC thickness, measuring 2.36 mm on fresh samples, while Quartzofeldspathic gneiss exhibited the greatest thickness in both slightly and moderately weathered conditions. Nonlinear logarithmic models were developed to predict the BFC thickness after 12 hours for all rock types and their weathering grades. To complement these findings, X-Ray Diffraction (XRD) tests were conducted to determine the major mineral compositions of the rock samples across weathering grades. The results indicated no direct correlation between mineral content and BFC formation, leading to the conclusion that BFC development is independent of mineral composition.
To assess the impact of BFC on the shear behaviour at the rock-concrete interface, a direct shear apparatus was fabricated at the University of Moratuwa (UOM) after a thorough literature review on similar apparatus. Direct shear tests were conducted under constant normal loading (CNL) conditions for all four rock types under a range of Bentonite infill conditions. Accordingly, Garnet granulite gneiss exhibited the highest shear strength, while Biotite gneiss displayed the lowest. Considering these findings, Biotite gneiss was selected for further shear testing, and samples were transported to the University of Wollongong (UOW), NSW, Australia for additional testing under CNL conditions. The tests confirmed the accuracy of the results given by the apparatus at the University of Moratuwa and established the base friction angle for the Biotite gneiss-concrete interface as 38.53°.
To further explore the effects of rough surface profiles, the least rough Biotite gneiss profile obtained from pile cores was converted into an equivalent triangular profile with a 3.5 mm asperity height and 80° asperity angles. This profile was tested at UOW under constant normal stiffness (CNS) boundary conditions of 8.5 kN/mm. The highest shear strength recorded was 3.53 MPa for a clean joint at initial normal stress of 0.705 MPa. The critical infill thickness where Bentonite began to govern shear behaviour was determined to be 4.5 mm. A new hyperbolic model was developed to estimate shear strength capacity for varying infill thicknesses of between 0 to 5.5 mm. In subsequent testing, a setup involving a thick steel pipe was used to apply higher CNS conditions of 215 kN/mm. Under these conditions, the maximum shear strength capacity of 9.76 MPa was achieved for the clean Biotite gneiss- concrete joint, while the lowest capacity of 2.86 MPa occurred with a 5.5 mm Bentonite infill. A new hyperbolic model was also developed to predict the maximum shear strength capacity under these higher CNS conditions.
Finally, data from 15 field load tests were utilized to analyse mobilized skin friction from the socketed regions of piles. These results were compared to the newly developed model, which was used to optimize skin friction design for pile rock sockets. Based on the findings, it is recommended to adopt the new model with a safety factor of 2.5, which would result in a potential reduction of construction costs for rock sockets by more than half.
item: Thesis-Full-text
Novel modeline methods and evaluation frameworks for assessing and improving the reliability of renewable-rich power systems
(2025) Amarasinghe, PAGM; Abeygunawardane, SK; Prasad , WD
The share of non-conventional renewable energy, such as wind and solar, is gradu ally increasing in many power systems. However, integrating wind and solar power on a large scale would considerably affect the reliability of power systems due to the stochastic nature of renewables. Conventional reliability evaluation methods cannot efficiently and accurately quantify power system reliability when there is a significant amount of renewable power in the system. Therefore, novel reliability evaluation tech niques are required to assess the reliability of modern renewable-rich power systems. This work implements novel modeling methodologies and evaluation frameworks to quantify the reliability of renewable-rich power systems accurately. Different algo rithms and techniques are developed to evaluate the reliability of generation, compos ite generation and transmission, and distribution subsystems because the nature of the problem and its complexity are different in each of the three subsystems. Firstly, a novel method based on Kernel Density Estimation (KDE) is proposed to model inter mittency and both diurnal and seasonal variations of wind and solar power generation using historical renewable power generation data. The proposed KDE-based renewable power models are used with Non-Sequential Monte Carlo Simulation (NSMCS) to evaluate the generation system adequacy of the Institute of Electrical and Electronics Engineers (IEEE) Reliability Test System (RTS) . The diurnal and seasonal varia tions of renewables and the correlation between the load and renewable generation are modeled in the proposed renewable power models. Secondly, the applicability of con ventional MCS for composite system adequacy evaluation is investigated. It is found that a more computationally efficient reliability evaluation methodology is needed to evaluate the adequacy of composite systems. Hence, a novel population-based intelli gent search method called Evolutionary Swarm Algorithm (ESA) incorporated with DC optimal power flow analysis is proposed to evaluate the adequacy of renewable rich composite power systems. The main objective of the ESA is to find out the most probable system failure events that significantly affect the adequacy of composite sys tems. The identified system failure events can be directly used to estimate the system adequacy indices. The random search guiding mechanism of the ESA is based on the underlying philosophies of genetic algorithms and binary particle swarm optimization. The computational efficiency of the proposed ESA is significantly higher than that of traditional simulation methods. Thirdly, the proposed ESA is used to evaluate the reli ability of solar-integrated power distribution systems. AC optimal power flow analysis is used to assess the system failure events while considering the feeder voltage levels. The annual reliability indices of renewable-rich distribution systems can be estimated using this method, which is not addressed in the prevailing literature. Apart from eval uating the power system reliability, the impact of increasing wind and solar integration on the reliability of power systems is investigated at all hierarchical levels. Further, the proposed reliability evaluation frameworks are used to identify possible methods to improve the reliability of power systems. The outcomes of this research allow precise planning and operation of modern power systems in a time-efficient manner.