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-Abstract
Safety climate in the Sri Lankan apparel industry : identifying gaps and strategies for improvement
(2025) Wijerathna, JARH; Madusanka, N
A significant portion of Sri Lanka workforce is employed in the apparel sector, yet there remains considerable potential to enhance safety standards within the industry. One major limitation to improving health and safety practices in workplace is the lack of detailed studies focused on the safety climate in apparel sector in Sri Lanka. This study mainly aims to assess workplace safety climates and identify gaps & effective strategies to strengthen the safety culture within the apparel industry in Sri Lanka. There are two phases in this study. Phase 01 involved a quantitative questionnaire survey administered to floor level employees across three ABC apparel companies, with a total of 90 participants; 30 from each company. The survey was structured around 12 key factors identified through literature review as affecting factors to safety climate: General Safety Overview, Management Commitment, Management Communication, Supportive Work Environment, Safety Rules and Procedures, Supervisory Environment, Appreciation of Personal Risk, Employee Involvement, Work Site Risks, Employee Competence, Work Pressure, and Safe Behavior. Phase 02 consisted of qualitative semi structured interviews with 15 managerial staff: five from each company. These open-ended interviews explored reasons for high or low safety climate factors and gathered comments on future improvement strategies. The findings revealed significant differences in safety climates across the three cases. Case A exhibited strong and consistent safety practices, Case B showed moderate safety performance with some gaps, while Case C highlights significant areas in need of improvement. The safety climate has been negatively impacted by several reasons i.e. High production targets, Language barriers, Limited budget allocations due to economic constraints, safety communication ineffectiveness with no strong platform to engage employees, Competency gaps in management, supervisory, and safety officer levels, absence of structured safety training, lack of recognition programs for safe behavior, etc. As a summary, these gaps in communication, training, leadership commitment, and employee involvement significantly lower the organization’s safety climate ratings. A proper enhancement of industrial safety climate requires strategies combining employee competency development, management commitment with visible leadership involvement and strong communication strategies. Apart from that OHS management system such as ISO 45001 and rewarding & recognitions programs are other key strategies involving improving the safety climate.
item: Thesis-Abstract
Prevalence and prevention of non-communicable diseases among technical personnel in the Sri Lankan Navy
(2025) Samarasinghe, AC; Dissanayake, P
The number of social sustainability audits on health and safety within Sri Lanka's export garment industry have increased significantly in recent times. Today, many customers are concerned not only about the quality of garments but also about the extent of compliance with standards and the reduction of incidents and accidents in factories. Although most export- oriented garment factories have established strong systems, non-conformities with standards and workplace incidents still occur. Building strong human capacities among internal operational staff is essential for creating a positive safety climate within organizations, including export garment factories. A positive safety climate naturally establishes to fewer non-conformities and a reduction in incidents and accidents. Therefore, it is crucial for organizations to invest in developing their human resources and to continuously plan and implement human capacity building initiatives to achieve better organizational outcomes. Human capacities can be categorized into six key areas: Cognitive Capacities, Technical and Professional Capacities, Physical, Social and Emotional Capacities, Moral and Ethical Capacities, and Adaptive and Resilience Capacities. Various drivers within an organization influence the development of these capacities. At the same time, there are barriers that challenge them. Many organizations adopt strategies to overcome these challenges, and it is vital that such strategies are both practical and relevant to their operational contexts. Thus, to achieve positive safety climate, it is necessary to develop human capacities of the internal staff in the export oriented garment factories. The methods that should adopt, current barriers and methods to overcome barriers will be discussed in research. Hence, the aim of this study was to propose a framework for human capacity development of internal staff in order to establish positive safety climate in export garment industry in Sri Lanka. Furthermore, the importance of the Human capacity development, Positive safety climate, currant drivers, barriers and strategies to overcome barriers will be discussed specifically for export garment industry. Qualitative research approach was adopted through Delphi method in order to achieve the research objectives by executing semi-structured interviews with 8 industry experts in the health , safety and compliance field in export garment industry. Finally developed a framework for human capacity building of internal staff. Consequently, a list of strategies were suggested to overcome the current barriers in the industry. Finally, a proposed version on human capacity building have developed based on expert suggestions and literature outcome in order to establish the positive safety climate of internal staff within the export oriented garment industry – Sri Lanka
item: Conference-Abstract
Study on methods of testing tensile strength of concrete
(Department of Civil Engineering, University of Moratuwa, 2025) Dole, ZR; Baskaran, K; Baskaran, K; Mallikarachchi, C; Damruwan, H; Fernando, FL; Herath, S
The tensile strength of concrete is a critical parameter in structural engineering, influencing crack resistance, durability, and overall performance. The brittle nature of concrete causes low tensile strength; hence, indirect methods for testing the tensile strength of concrete, such as the Direct Tension Test, Brazilian Splitting Test (BST), Flexural test, and other novel methods, present limitations related to stress distribution and real-world applicability. This research attempts to further investigate the applicability of a novel method by making certain improvements to past studies of a similar setup for determining the tensile strength of concrete using direct axial force and compares its performance with BST and Cube Compression Test (CCT) across different concrete ages and grades. The experimental procedure involved testing concrete grades C25 and C35 at 3, 7, 14, 28, and 56 days. Specimens were cast in separate batches and subjected to three testing methods: the novel method of Modified Direct Tension Test (MDTT), the Brazilian Splitting Test (BST), and a Cube Compression Test (CCT). The unstandardized MDTT specimen details, dimensions, and method of testing have been described, enabling further research on the proposed method. The novel method aims to provide a more representative measure of direct tensile behaviour while addressing limitations observed in BST. Tensile strength values obtained from both methods are analysed and compared, alongside cube compression test results, to establish correlations between tensile and compressive strengths. Preliminary findings suggest that the newly introduced method may offer improved reliability in capturing tensile failure mechanisms. The results also suggest that the tensile strength vs compressive strength gain patterns vary with time for both tensile strength testing methods. It was also found out that the novel method provides consistent results, and the specimen modification made to direct the tensile crack at the centre is successful in more than 80% of the cases. This research further attempts to discuss the practical applications for the MDTT in cases such as Precast concrete evaluation, bridge and tunnel structural performance, and FRC & UHPC strength and quality assessments. Modifications to be made to the testing apparatus to make it a more reliable method of testing the tensile strength of concrete are also discussed. Further recommendations have been provided to increase the number of test cases and investigate the influence of strain rate on the MDTT setup, which would contribute to the development of concrete testing methodologies as an alternative approach that would enhance accuracy and practical implementation in structural assessments.
item: Conference-Abstract
Simulation of ultrathin membranes with curved creases
(Department of Civil Engineering, University of Moratuwa, 2025) Bandara, NRSM; Mallikarachchi, HMYC; Baskaran, K; Mallikarachchi, C; Damruwan, H; Fernando, L; Herath, S
Origami-inspired structural systems have attracted increasing interest in engineering due to their lightweight, compact, and highly deployable characteristics. While straight-crease origami has been extensively studied, it often leads to geometries with sharp folds and limited adaptability. In contrast, curved crease origami enables smoother surfaces, reduced crease density, and enhanced geometric versatility—features that are advantageous in aerospace, architectural, and robotic applications. However, modelling such systems remains challenging since the panels experience coupled bending and stretching, violating rigid-folding assumptions commonly used in straight-crease analysis. This study investigates the applicability of the Bar and Hinge model for simulating ultrathin membrane structures with curved creases.
The research aims to (i) validate the Bar and Hinge model for single-curved crease configurations by comparison with experimental and finite element (FE) results, and (ii) extend the analysis to multi-curved crease systems, exemplified by a waterbomb-base geometry, to assess overall folding behaviour. In this framework, the sheet is discretised into interconnected Bar and Hinge elements that capture in-plane stretching, out-of-plane bending, and fold rotation. Curved creases are represented by approximating the fold path with multiple short straight segments.
A single-curved crease specimen, modelled using A4 paper properties, was analysed under controlled boundary conditions and prescribed displacements. The predicted folded shape showed good agreement with both experimental observations and FE simulations performed using ABAQUS commercial FE package. Minor discrepancies in curvature distribution were mitigated by mesh refinement, which improved correspondence with reference results. Energy decomposition indicated that increasing crease curvature reduces global bending energy while increasing local folding energy, illustrating the mechanical trade-off intrinsic to curved crease mechanisms.
The waterbomb base, featuring six alternating curved folds, was subsequently simulated to evaluate model performance in multi-crease configurations. The model successfully reproduced the characteristic saddle-like folded form and exhibited bistability. Coarse discretisation introduced minor asymmetry, which was corrected through mesh refinement, demonstrating the sensitivity of the method to mesh quality. Overall, the findings confirm that the Bar and Hinge model provides a viable and computationally efficient approach for analysing single- and multi-curved crease origami. Nevertheless, its current limitations include difficulty in capturing double curvature within a single panel and dependence on discretisation density. Future work will involve experimental validation of multi-crease geometries and model enhancement to improve predictive fidelity for complex curved crease origami systems
item: Conference-Abstract
Analysis of machine-induced floor vibrations in buildings using experimental and numerical approaches
(Department of Civil Engineering, University of Moratuwa, 2025) Dilthusha, MPI; Damruwan, HGH; Baskaran, K; Mallikarachchi, C; Damruwan, H; Fernando, L; Herath, S
Machine-induced floor vibrations in buildings pose significant challenges to structural integrity and occupant comfort, necessitating effective mitigation strategies. The overall purpose of this study is to analyse the dynamic response of structural elements under machine-induced vibrations and evaluate various techniques to mitigate these vibrations. This research addresses the problem of excessive vibrations caused by harmonic and periodic dynamic loads from machinery, which can lead to structural issues such as cracking, fatigue, and loss of bearing capacity, as well as discomfort for building occupants. This research employs a comprehensive methodology, combining experimental, numerical, and field investigations. An experimental setup involving a steel plate subjected to impact loading was used to measure vibration characteristics, including Peak Particle Velocity (PPV) and frequency. Finite Element (FE) models were developed using SAP2000 software and validated against experimental and field data to simulate vibration behaviour. Field measurements were conducted at two case study sites: a research lab in the selected factory building, where treadmill-induced vibrations disrupted motion-capture equipment, and a pump house, where pump operations caused localised vibrations in concrete platforms. Key findings reveal that structural parameters such as slab thickness and span length significantly influence vibration response. Thinner slabs and longer spans amplify vibrations, while thicker slabs reduce PPV. The results obtained from the FE models showed strong correlation with experimental results, with most errors below 5%, confirming the validity and reliability of the numerical simulations. Field data highlighted the localised nature of vibrations, with PPV values reaching 4.674 m/s in the factory building and frequencies up to 13.49 Hz in the pumphouse. The study also identified resonance risks when structural natural frequencies align with machinery operating frequencies.
Principal conclusions emphasise the importance of conducting early-stage dynamic analysis in design to avoid resonant conditions and the need for structural modifications, such as increasing stiffness or optimising spans, to mitigate vibrations. The research underscores the practical significance of integrating experimental and numerical approaches for accurate vibration assessment and mitigation. Recommendations include adopting design codes that prioritise vibration serviceability limits and exploring retrofitting strategies for existing structures. This study contributes to the field by providing empirical insights into vibration control, thereby bridging the gap between theoretical models and real-world applications. Its findings are vital for ensuring the safety, durability, and functionality of buildings subjected to dynamic loads, benefiting both structural engineers and designers.