Browsing by Author "Damruwan, HGH"

Now showing 1 - 7 of 7

item: Conference-Abstract
Assessment of disaster resilience in hospitals: a case study based framework development for Sri Lankan context
(Department of Civil Engineering, University of Moratuwa, 2024) Marasinghe, MMGC; Damruwan, HGH; Siriwardana, CSA; Dhanapala, S; Wijesekara, N; Wedamulla, A; Pasindu, HR; Damruwan, H; Weerasinghe, P; Fernando, L; Rajapakse, C
Hospitals are essential infrastructures that must maintain continuous operation during and after disasters to ensure the safety of patients and staff while providing medical services, even under surge conditions. Given the critical nature of these facilities, assessing their disaster preparedness is of utmost importance. This study addresses the limitations of the World Health Organization's Hospital Safety Index (HSI) when applied to Sri Lankan hospitals, leading to the development of the Structural Safety of Hospitals Assessment for Sri Lanka (SSH-SL). The study presents a comprehensive framework for evaluating hospital safety, divided into three primary modules: structural safety (utilizing SSH-SL), functional safety, and emergency and disaster management. Enhancements were made to the latter two modules to better align with the specific needs of the Sri Lankan context. The framework introduces a set of equations to calculate the safety index for each module, which then assigns safety levels and provides recommendations for improvement. This framework was applied to assess 15 government hospitals, revealing significant concerns across all three modules, underscoring the need for targeted interventions to enhance hospital resilience in Sri Lanka. The results from the assessment indicate that the structural safety levels of the 15 hospitals are generally at or above average level, suggesting that these facilities can operate during disaster conditions, though steps must be taken to ensure safety of both patients and staff. In terms of functional aspects, the majority of hospitals demonstrated a safety level of average or above, with two hospitals exhibiting below-average safety levels. Regarding Emergency and Disaster Management, 11 out of the 15 hospitals displayed high safety levels, whereas two hospitals had low safety levels. Immediate actions are necessary for hospitals with below-average safety levels, with a focus on implementing both short-term and long-term remedies. Additionally, limitations of the framework were identified during the hospital assessment process. The architectural safety submodule, under functional safety, was recognized as a critical submodule requiring modifications. Several assessment criteria specific to the Sri Lankan context were identified and subsequently incorporated into the existing submodule. Following these adjustments, a Delphi Study was conducted on the enhanced submodule, utilizing a panel of experts to gauge their consensus. Based on the survey results from the Delphi Study, weights were assigned to each assessment criterion within the submodule, leading to the derivation of a comprehensive safety score for the architectural safety of hospital buildings.
item: Conference-Full-text
A comparative study on the mechanical properties of concrete by substituting cement with sugarcane bagasse ash
(IEEE, 2023-12-09) Sankeeth, S; Kumara, BS; Damruwan, HGH; Herath, HMST; Lewangamage, CS; Koswattage, KR; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
This research study compares the mechanical properties of concrete by substituting Sugarcane Bagasse Ash (SCBA) at various weight ratios for Ordinary Portland Cement (OPC) and Portland Composite Cement (PCC). The study was mainly concerned with determining the consistency, setting time, workability, compressive strength, and split tensile strength of concrete mixes containing different percentages of SCBA. Three replacement scenarios were considered into account: 0% SCBA (control sample), 5% SCBA, and 10% SCBA, which would have replaced both OPC and PCC. Various tests were conducted according to relevant standards to evaluate the performance of the concrete mixes. The results revealed that replacing 10% of OPC with SCBA performed better than replacing PCC and the control samples. Higher compressive strength and split tensile strength were among the improved mechanical characteristics of the concrete mixtures with 10% SCBA. These results show the possibility of using SCBA as a partial cement substitute to enhance the overall performance of concrete, especially when replacing OPC. This research offers important insights into sustainable construction practices by identifying SCBA as a feasible cementitious material with favorable economic and environmental effects. The results may assist researchers and concrete experts in optimizing the use of SCBA in concrete mix designs to achieve desired mechanical properties and enhance sustainability in the construction industry.
item: Conference-Abstract
Eurocode loads and the implications for the structural design of box culverts in Sri Lanka
(2019) Sumanasinghe, Y; Jayasinghe, MTR; Damruwan, HGH
The Reinforced Concrete Box Culverts are drainage structures that allow to cross, small to medium scale water paths. They generally founded in soil where scouring is not an issue. The advantage of the box culvert is that it can be rested on the soil where low bearing pressures exists. Box structures are also often used in expressway construction when underpasses are needed for the traffic of by-roads that crosses the expressway embankment. The present highway structure design practice in Sri Lanka is based on the British Standard, BS 5400, that was published by British Standard Institution (BSI) in 1978 and then amended, number of times subsequently and along with the Bridge Design Manual (1991), published by Road Development Authority (RDA), the apex body of managing A & B class of roads in Sri Lanka. Since the BS codes have been superseded by BS EN (the English version of Euro Codes) in March, 2010, it is now opportune to adopt the recommendations of BS EN for the structural design of highway structures and hence box structure design will also need updating. In this paper, a detailed study has been carried out as a comparative study by considering number of possible arrangements of reinforced concrete box structures that are typically used in Sri Lanka. The reason is that BS EN allows a loading regime from which different values can be selected in contrast to the current BS based practice. The detailed analysis, with Finite Element Method (FEM) , has been carried out for different types of loading specified in the BS EN; the results have been compared with the resulting effects of currently adopted standards to find suitable loading levels that can be recommended for the adoption in Sri Lanka. The results are presented in graphical form to allow the selection of different levels of loading based on the effects on the main design parameters.
item: Conference-Abstract
Investigate the behaviour of glass balustrades under human impact loads
(Department of Civil Engineering, 2023-09-27) Wanigasooriya, TWMC; Damruwan, HGH; Mallikarachchi, C; Hettiarachchi, P; Herath, S; Fernando, L
Glass balustrades are extensively used in various settings and are frequently subjected to different impact loads, including rigid or soft body impacts (human impacts). Ensuring the safe design and installation of glass balustrades to withstand these impact loads is crucial for minimising the risk of injuries caused by falling glass fragments. This research studies the behaviour of simply supported glass panels when subjected to different impact locations and speeds. A comprehensive field survey was carried out to investigate the support conditions, glass types, and their behaviour under human impact loads. A Finite Element (FE) model of a pendulum impact test was developed to analyse and understand the response of tempered glass panels under human impact loads. Specifically, the horizontal and vertical strains of the glass plate were used to validate the FE model. Additionally, a parametric study was carried out to examine the deflection patterns of the glass plate under impact loads, considering various impact locations and speeds. This research highlights the lack of public awareness regarding the safety requirements of glass balustrades, emphasising the need for education and guidelines. Results obtained from the FE model agreed well with experimental data for drop heights below 700 mm, while acceptable deviations (-10% to +10%) are still observed for higher drop heights. Furthermore, the impact location significantly influences the maximum deflection in glass balustrades, with shifts towards the impact location observed at higher impact energies. The research findings highlight that the horizontal strain consistently surpasses the vertical strain across all drop heights. These insights provide valuable information for glass balustrades’ design, installation, and maintenance processes, ensuring their safety and dependability in reallife situations involving soft body impact loads, such as human impacts.
item: Article-Full-text
Investigation of pozzolanic properties of sugarcane bagasse ash for commercial applications
(American Chemical Society, 2023) Prabhath, N; Kumara, BS; Vithanage, V; Samarathunga, AI; Sewwandi, N; Damruwan, HGH; Lewangamage, S; Koswattage, KS
The ideal climatic and environmental conditions for sugarcane cultivation are present all year round in the tropical island of Sri Lanka. Given the annual sugar consumption of the nation, a significant amount of sugarcane bagasse ash (SCBA), a by-product with no intended commercial use but potential environmental and health risks, is produced. Numerous studies have been conducted recently to assess the viability of using SCBA as a pozzolanic material in structural applications. The purpose of this study is to evaluate the microstructure of SCBA samples from three sugar manufacturing facilities in Sri Lanka to identify the pozzolanic capacities. Several quantitative and qualitative characterization techniques have been utilized for the investigations. While maintaining the American Society for Testing and Materials (ASTM) 618 specification as the standard for pozzolanic properties, a comparative investigation of the attributes of samples from each location was conducted. Beyond that, the relationship between the SCBA generation process parameters and their impact on the properties of SCBA have been identified. Finally, the SCBA source of the Pelwatte unit has been identified as the ideal source for the pozzolanic material from the three locations, considering quality and the extent of additional treatments required before use. Other prospective areas of research on SCBA and its potential applications have been recognized.
item: Conference-Abstract
Investigation of the drift performance of point fixed glass façade systems under varying flexibility of spider arm Connections
(Department of Civil Engineering, University of Moratuwa, 2024) Suraweera, MV; Damruwan, HGH; Pasindu, HR; Damruwan, H; Weerasinghe, P; Fernando, L; Rajapakse, C
Glass façade is a key component in contemporary architecture, offering both aesthetic appeal and structural functionality. Among the various facade systems, Point-Fixed Glass Façade (PFGF) systems stand out for their elegance and adaptability. However, their drift performance when subjected to in-plane racking actions due to seismic and wind forces is a significant concern, particularly in regions with low to moderate seismic risk, where such factors are often neglected during the design phase. Additionally, there is a notable scarcity of research on PFGF systems, particularly concerning parametric studies that explore drift capacity while considering the flexibility of spider arms. This study addresses this gap by presenting an in-depth analysis of the in-plane drift performance of PFGF systems. A comprehensive Three-Dimensional (3D), non-linear Finite Element (FE) model was meticulously developed using ANSYS software, incorporating non-linear material properties and 3D elements to accurately and realistically represent the behavior of spider arms under loading conditions. To ensure a balance between model accuracy and computational efficiency, a detailed mesh sensitivity analysis was conducted to determine the optimal mesh size. The developed FE model was thoroughly validated against experimental data from previous studies, evaluating key parameters such as pushover curves, drift capacity, and maximum in-plane displacements. The validation demonstrated that the FE model achieved a drift capacity of 2.12% with a corresponding force of 15.97 kN, closely matching the reported experimental results. Additionally, a separate 3D linear FE model was developed to compare the outcomes between linearly and non-linearly modelled spider arms, further highlighting the critical importance of incorporating material nonlinearity in significantly enhancing the accuracy of the developed FE model. The parametric study conducted on the PFGF system provided valuable insights into its drift performance under various configurations. Findings indicated that reducing the thickness of spider arms significantly improves drift performance, albeit with a minor reduction in allowable force. Similarly, decreasing the width of spider arms enhances drift performance, though at the cost of a noticeable reduction in allowable force. Increasing the diameter of the circular and slotted holes in spider arms improved drift performance, with a slight rise in allowable force. Moreover, decreasing the rotational friction at the base connection of the spider arm led to a modest enhancement in drift performance, with minimal impact on the allowable force. These results provide critical insights for engineers designing PFGF systems, emphasizing the importance of optimizing spider arm configurations to enhance drift capacity. The study underscores the need for considering structural interactions in facade system design to mitigate risks associated with seismic and wind loads. The validated FE model and the derived parametric insights are instrumental in guiding future design practices and improving the resilience of PFGF systems in various loading conditions.
item: Conference-Abstract
Rapidly constructed two storey thermally comfortable houses for tropical climates with light weight loadbearing concrete panels
(2019) Eric, TB; Gunawardana, SGW; Hasalanka, HHH; Jayasinghe, MTR; Damruwan, HGH
Apartments in tall buildings are often promoted as a solution to rapid urban migration that is happening in the world. However, all the apartment houses that have been undertaken in many parts of the world in large cities have not resulted in desirable results all the time. Therefore, it would be prudent to have high-density developments on small blocks of land with detached or semi-attached housing. Such high-density developments will be a special challenge in tropical climates when the urban heat island effects are considered since a high density of houses can often lead to lack of green cover, and hence to have somewhat higher temperatures than the averages predicted for that locality. The other biggest challenge that is faced in countries with tropical climatic conditions is the extensive use of natural resources based walling materials like fired clay bricks, concrete blocks, etc.; this practice has led to over-exploitation of natural resources and hence it is prudent to explore the possibility of using alternative sources that will use much less amount of natural resources. In this context, converting various types of waste materials to a useful building material will also play a major role. One such material is the lightweight concrete panels produced to have 70% of the volume as air using recycled already used Expanded Poly-Styrene (EPS) panels manufactured in modular form with the dimensions of 0.6 m of length, 2.4 m of height and in thicknesses of 75 mm, 100 mm, 150 mm, etc. The use of panels instead of individual small units will allow rapid construction of a house, and it is shown that it is possible to complete one such house having about 200 m2 with a rooftop terrace in less than 30 working days by employing 6 Nos of semi-skilled workers. In a detailed study carried out on with the tropical climatic conditions prevailing in Sri Lanka as a case study, it is shown that there are so many strategies that can be very effectively used to make such houses extremely thermally comfortable while almost eliminating the heat island effects even if a high density has been achieved with individual blocks as small as 200 m2. The research paper is intended to describe all these aspects by taking an actual two storey house with roof terrace constructed in Sri Lanka in the wet zone.