CERS - 2024
Permanent URI for this collectionhttp://192.248.9.226/handle/123/22814
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Browsing CERS - 2024 by Author "Ariyaratne, IE"
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- item: Conference-AbstractConstruction quality framework for school buildings in Sri Lanka(Department of Civil Engineering, University of Moratuwa, 2024) Thoradeniya, BRWMD; Jayasinghe, C; Ariyaratne, IE; Pasindu, HR; Damruwan, H; Weerasinghe, P; Fernando, L; Rajapakse, CThe built environment of schools plays a crucial role in shaping the educational experience, yet Sri Lanka has faced ongoing concerns regarding the quality of school construction, despite significant government investment in education. To address this issue, a comprehensive study was conducted with the primary objective of developing a construction quality framework specifically tailored for school buildings in Sri Lanka. This framework aimed to establish clear standards and guidelines for the design, construction, and maintenance of school buildings, ensuring that they meet the necessary safety, functionality, and sustainability criteria. An extensive literature review was undertaken to systematically break down the processes involved in school building construction and to conduct background research on contemporary quality standards. The breakdown included the following key phases: project initialization, design and construction, operations and maintenance, and rectification and building condition. Data collection was carried out through multiple methods, including case study reports from the National Building Research Organization (NBRO), which covered 58 buildings across 22 schools. Surveys of school stakeholders and expert interviews were also conducted. The NBRO reports included visual observations and both destructive and non-destructive testing techniques. The survey aimed to assess the efficiency of operations and maintenance processes, while expert interviews provided insights into the procurement procedures of school buildings. The collected data were analysed using statistical methods to categorize and prioritize the defects identified in the construction process. This analytical approach facilitated the identification of the most common and critical defects, along with their correlation to the overall condition of the buildings. The defects were categorized based on their location and severity, offering a clear understanding of recurring issues in school construction. The analysis revealed significant issues in design, construction, and maintenance practices, with gaps in maintenance protocols and challenges such as financial constraints and bureaucratic delays. The importance of addressing these defects proactively, particularly in critical structural elements such as slabs, columns, and beams, was emphasized to ensure the durability and safety of school buildings. The proposed framework was validated through its application to a school building construction project in the Northwestern Province, which encompassed two phases—one completed and the other ongoing. This validation demonstrated the framework's effectiveness in improving construction quality and addressing prevalent issues. The outcomes of this methodological approach provided valuable insights into the construction quality of school buildings in Sri Lanka. By identifying and prioritizing defects throughout the entire construction process, the study established a basis for minimizing or eliminating these issues in future construction projects. The insights gained from this research contribute to the formulation of targeted construction guidelines for school buildings in Sri Lanka, aligning with the evolving needs of the Sri Lankan education system.
- item: Conference-AbstractDevelopment of a damage assessment matrix for load-bearing masonry houses(Department of Civil Engineering, University of Moratuwa, 2024) Thalpage, SL; Jayasinghe, C; Ariyaratne, IE; Pasindu, HR; Damruwan, H; Weerasinghe, P; Fernando, L; Rajapakse, CMasonry houses are common types of buildings constructed using materials like bricks, stones, or concrete blocks. They are popular due to their durability and aesthetic appeal. However, as masonry structures age, they become vulnerable to various forms of crack damage that can potentially compromise their structural integrity and the safety and comfort of their occupants. While numerous studies have examined the condition assessment of buildings, they primarily rely on visual inspection conducted by inspectors who often base their evaluations on personal experience, biases, and risk attitudes. Recognizing the absence of a standardized method for assessing wall crack damages, this research study was aimed at developing a crack damage assessment matrix specifically focusing on single-story, load-bearing masonry houses. A database surrounding over 270 instances of cracks in approximately 60 houses from the Higurankgoda area in Sri Lanka, is considered to determine the key factors influencing the damage severity and safety of the house. Severity considerations include crack length, width, and number of cracks in the wall, while safety factors encompass crack severity level, separation level of the crack, surface condition of the cracked wall, crack location, crack direction, and structural degradations. To construct a data-driven prioritization matrix, the study employs the Analytical Hierarchy Process (AHP) and a probability-based approach, utilizing real-world data to assign reliable weightage to each parameter. This research determines the influence weightage of each parameter on overall safety and stability. The calculated weightage results indicate that the parameter with the highest impact is from the structural degradations, while the parameter with the lowest impact is from the crack direction. This matrix facilitates a Risk Level Index (RLI) to assess the overall impact of individual cracks and a systematic approach is proposed to determine the overall risk level of the house. The systematic approach illustrates the risk level for the house when it has varying numbers of wall cracks based on the generated RLI value and the number of cracks in each influence category. Fifteen single-story load-bearing masonry houses were selected for the testing and verification of the developed matrix, and the outcomes of the matrix were compared with the already assigned risk levels by experts for each house. The proposed matrix was tested and validated with more than 80% accuracy level. This prioritization matrix will empower engineers, and homeowners to efficiently prioritize repair efforts and allocate resources based on potential risk. The proposed approach integrates advanced analytical techniques with practical insights to enhance decision-making in addressing wall crack damages in masonry houses.
- item: Conference-AbstractEvaluating the structural performance of masonry wall panels constructed with glass waste aggregate blocks(Department of Civil Engineering, University of Moratuwa, 2024) Mapa, RMMND; Jayasinghe, C; Ariyaratne, IE; Pasindu, HR; Damruwan, H; Weerasinghe, P; Fernando, L; Rajapakse, CThe construction industry faces a significant challenge in the form of high costs associated with construction materials. As a means of addressing this challenge, the industry has explored various alternatives to reduce costs. One such effort includes the use of alternative or waste materials in construction. The adoption of waste materials in the construction industry offers a viable solution to natural resource depletion while providing an opportunity for proper solid waste management. The construction industry relies heavily on the use of bricks and blocks, which require significant quantities of natural resources. As a result, considerable research has focused on the introduction of waste materials into the bricks and blocks manufacturing process, such as Glass Waste, waste tea, rice husk ash, crumb rubber, and cement kiln dust, as a substitute for sand. Among these materials, glass waste plays a particularly prominent role in increasing municipal solid waste. According to current literature, the compressive strength of masonry units is dependent on the percentage of glass waste used, with peak strength observed at 20%-25% replacement. Beyond this threshold, subsidence becomes noticeable. The maximum replacement percentage that can be used without significantly reducing the compressive strength of general masonry units is 50%. However, it is essential to evaluate masonry strengths, rather than just masonry unit strengths, when designing walls within the framework of construction quality. This research aims to evaluate the compressive and flexural strength of wall panels cast from masonry units in which 50% of the fine aggregate has been replaced with glass waste. The study will compare the results obtained with that of the strength requirement specified in the BS EN 1996-1-1. The compressive strength of GWAB is observed to be higher than that of CSB, as reported in the literature. However, experimental values indicate a significant reduction in compressive strength as compared to the values calculated from BS EN 1996-1-1. In light of this, 𝐾𝐺𝑊𝐴𝐵=0.48 factor has been defined for the design of wall panels according to equation 3.1 in BS EN 1996-1-1 using general-purpose mortar and GWAB. Furthermore, the equation 3.1 in BS EN 1996-1-1 can be redefined as follows with the 𝐾𝐺𝑊𝐴𝐵 factor. 𝑓𝑘=𝐾𝐺𝑊𝐴𝐵𝐾𝑓𝑏𝛼𝑓𝑚𝛽, definitions of other parameters in the equation defined in BS EN 1996-1-1. This factor is crucial for ensuring optimal performance and durability of the wall panels. The characteristic flexural strength of GWAB wall panels perpendicular to the bed joint and parallel to the bed joint was compared with the theoretical and experimental values of CSB wall panels and graphically represented in the charts.
- item: Conference-AbstractInvestigating residual properties of masonry units at elevated temperatures(Department of Civil Engineering, University of Moratuwa, 2024) Rajapaksha, TDCM; Ariyaratne, IE; Jayasinghe, C; Pathirana, HR; Damruwan, H; Weerasinghe, P; Fernando, L; Rajapakse, CMasonry structures are renowned globally for their strength, durability, affordability, and thermal and sound insulation properties. However, there is limited information on the residual properties of masonry units after exposure to elevated temperatures. This research addresses the aforementioned gap by investigating the residual properties of four representative masonry units; clay bricks, concrete blocks, compressed stabilized earth blocks and lightweight foam blocks. The study aimed at determining variations in physical and mechanical properties, including visual appearance, density, and compressive strength of these masonry units after exposure to elevated temperatures. Additionally, conventional cement-sand mortar (1:6) was also tested both in their ambient state and after exposure to elevated temperatures. The study involved an experimental approach where four types of masonry units named clay bricks, concrete blocks, compressed stabilized earth blocks (CSEB), and lightweight foam blocks were subjected to controlled elevated temperatures up to 1200°C using a muffle furnace. Physical and mechanical properties, including density and compressive strength were measured both prior and post stages of exposure to these temperatures. Variations in these properties were then analyzed to assess the residual performance of each masonry unit. Visual observations and Scanning Electron Microscopy (SEM) were examined to document surface alterations and microstructural changes after exposure to elevated temperatures. Further, characteristic compressive strength values of the masonry assembly were also calculated using an empirical equation in the ambient and residual states. Finally, a comparative analysis between ambient and elevated temperature conditions was conducted to assess the impact of elevated temperatures on the masonry units and mortar. The results indicate that the compressive strength values of masonry units and mortar decrease after exposure to temperatures up to 1200°C. The reduction factor in compressive strength of each unit after full heating process were observed as 0.57, 1, 0.68, 0.88 for clay brick, CSEB, lightweight foam block and CMU respectively. Clay bricks exhibited better resistance than other types, retaining most of their initial strength after exposure to elevated temperatures. Compressed stabilized earth block was observed to fail into a brittle failure after exposure to 1200°C. Dry density of all four types decreased significantly after exposure to elevated temperature conditions. Additionally, residual compressive strength of generally used mortar (1:6) exhibited a clear reduction after exposure to elevated temperature conditions. The study's primary contributions include the investigation of the residual state behaviour of masonry structures after exposure to elevated temperatures which simulates the close behavior of a masonry structure at post-fire condition. This understanding aids in selecting appropriate masonry materials in a fire-prone area in future masonry construction.