Workshops, Seminars, Symposiums & Conferences

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item: Conference-Full-text
Thermal Performance of Precast Panel Buildings
(University of Ruhuna, 2023-03-16) G.W.T.I. Madhushanka; S.S. Bandaranayaka; M.T.R. Jayasinghe; H.M.S.T. Herath; T.M. Rengarasu
Energy consumption by buildings plays a major role in the sustainable and economic development of a country. In Sri Lanka, the electricity supply is not adequate to meet the rising demand. Therefore, the cost of electricity can be expected to increase in the future, resulting in a corresponding increase in the operating cost of dwellings. Several energy-efficient building materials with low thermal conductivities have been developed to increase the thermal comfort of buildings and reduce operational costs. Precast sandwich panels were assumed to be one of them. This paper presents a comparative study among precast panels, bricks, and hollow concrete blocks to evaluate the merits of precast sandwich panels and methods to increase their thermal performance. A selected housing unit was modeled and analyzed for thermal performance using DEROB-LTH for different wall materials. From the obtained results, it shows the window area is a crucial factor and for a low window area, the most thermally favorable material is precast panels. Then the model was altered to investigate the passive techniques that can apply to the house for better thermal comfort. It was recommended to use window shadings with sufficient length and to increase window opening percentage.
item: Conference-Full-text
Adoption of Precast Hollow Core Panels for External Walls of Multistorey Buildings
(University of Ruhuna, 2023-03-16) R. Subakaran; H.M.S.T. Herath; M.T.R. Jayasinghe; T.M. Rengarasu
Due to the increasing population and reduced availability of usable lands for construction activities, many residential and commercial buildings are becoming medium- to high-rise structures globally. Complementing this trend, the Sri Lankan construction industry has incorporated precast products as core elements in several projects due to their better performance, enhanced quality, elevated control, reduced leading time of construction, adaptability of novel technologies in construction and controlled material processing during manufacturing. During the past decade, precast wall panels became one of the popular precast panel elements satisfying both load-bearing and non-load bearing structural requirements in Sri Lanka. Originally, precast wall panels were intended to be used as internal partition wall panels, which are not expected to resist loading nor undergo significant deformations. This paper focuses on verifying the usability of such precast panels as external wall panels in multi-storey buildings, where their load resistance is investigated under lateral wind loads and vertical deformations due to column shortening effects. In addition, using the shape optimization technique in-built into ABAQUS CAE advanced finite element software, a better layout for the precast wall is also proposed and their performance is compared with the current standard layout under similar loading and boundary conditions. It was found out that the optimized precast hollow core panels are 19.88% less in volume with similar performance and can be used as external wall panels to withstand wind induced lateral loads in multistorey buildings. The recommendations on how many panels shall be used in a single assembly are also presented.
item: Conference-Abstract
Simultaneous Development of Research Skills and Environmental Awareness through Library Orientation : a Case Study
(Sri Lanka Library Association, 2022-09-21) Seneviratne, Thushari; Jayawardena, Chulantha; Cabral, U. P.
The Sustainable Development Goals (SDGs) are divided into three categories: economic, social, and environmental. Of the 17 SDGs that were introduced by the United Nations Department of Economic and Social Affairs, goals from 13 to 15 can be considered as directly related to the environment. Environmental awareness is important for every individual to minimize the influence of man-made disruptions and ensure the long-term sustainability of the environment and society. For the above purpose, adequate knowledge sharing and sufficient access to relevant, up-to-date information would be essential. The libraries can be effective facilitators, provided innovative strategies which are deployed to engage with the users. Traditionally, libraries would be mostly responsible for developing an information collection and enabling users to access those resources. Accordingly, the library orientation sessions for undergraduates would primarily consist of showcasing and familiarizing them with the variety of resources available for reference, typically through several mutually exclusive examples. In contrast, this study, based on the student feedback survey results, has been conducted with several instances of a single realistic example that is familiar and has a sensible as well as significant storyline. In order to develop research skills and environmental awareness simultaneously, the library orientation session on "first steps in research" for the most recent intake of engineering undergraduates at the University of Moratuwa was adapted to raise environmental awareness of the Bologoda wetland system. It is the largest freshwater wetland arrangement with a high ecological, social, and economic value, in addition to having the Bolgoda Lake adjacent to the university premises. A lecture on the importance of literature review in research was followed by an introductory situational awareness of Bolgoda Lake and the wetland system prior to allowing the students to perform a guided literature survey to retrieve information from a variety of sources. This included choosing a topic from among five specific areas on the Bolgoda wetland system, namely: illegal encroachment and landfilling in the Bolgoda area; flood risk management through the Bolgoda wetland system; waste dumping adjacent to Bolgoda lake; the impact of water pollution on the biodiversity of Bolgoda lake; and the economic benefits of developing recreational activities in Bolgoda lake. Out of 812 online participants, 792 submitted the assignment and feedback through a circulated Google form, where Likert scale was used to measure the level of awareness and perception of the session content. The results revealed that the awareness of the Bolgoda ecosystem had significantly improved from "Poor" 36.05 % to 0 %; "Fair'' 14.01% to 5.44 %; "Satisfactory" 13.61 % to 24.49 %; "Very Good" 4.08 % to 45.58 % and "Excellent" 12.24 % to 24.49 %. Furthermore, the majority of the participants were active (90.35 %) throughout the session with a satisfaction of 94.55 % for learning outcomes, 92.47 % for session content, and 90.27 % for assignment activity. In comparison to the previous records of identical exercises annually conducted by the library for fresh undergraduates, these are the highest achieved in terms of activity and successful rates. In conclusion, this reveals that the library could effectively be involved with environmental awareness development across the domains of undergraduate education, which directly contributes to the future decision-makers while catering to the requirements of SDG’s.
item: Conference-Abstract
Citation analysis of Masters in Information Technology theses available in Library, University of Moratuwa
(National Library and Documentation Services Board, 2022-09-08) Seneviratne, T.M.; Kodikara, R.C.
Library records indicate postgraduates reading for MSc. in Information Technology use less printed information resources. Library University of Moratuwa has subscribed reputed databases in such subject specialties. Though downloads from these databases are significantly increasing, their real usage has not been evaluated. By analyzing citations of theses and dissertations of MSc. in Information Technology, usage information resourcescan be identified.Population of the study comprises 250 Masters in Information Technology theses of Faculty of Information Technology, University of Moratuwa submitted during 15-year period from 2006-2020. Stratified random sampling was used to select sample of 152 theses according to the year of submission. Three thousand five hundred seventeen citations were found in 152 MSc. in Information Technology theses with 23 average citations per thesis. More than 50 % of the citations were within the period from year 1996 to 2020.Majority of citations are from Websites (38.24 %). Journals (23.20 %), books (16.12%) and conference proceedings (12.88 %) dominate thereafter. Majority of the information sources cited are available electronically (70.4 %). When authorship patters are considered, it was found 781 citations are by individual authors; 1313 publications by corporate authors and 1416 publications by multiple authors. Though affiliation could not be identified in 40.3 % citations, others belong to 50 countries and United States of America (14.3 %) in the highest position. Majority (23) of the studies have been carried out in the sub-field of Information Systems and ‘Software Engineering’ by Ian Sommerville ranked first (12.5 %) among 184 authors and co-authors of books. International Journal of Computer Applications received 5.63 % of citations. Five out of 10 highly ranked journals are available in subscribed databases of Library, University of Moratuwa. Out of 141 listed conferences, 49.64 % of the conference proceedings are available in IEEE Explore Digital Library; 32.6 % are available in ACM Digital Library; 2.1 % are available in both databases. It can be concluded that current Library collection is mostly utilized to satisfy research needs physically as well as electronically.
item: Conference-Full-text
“Kuweni” the first female ruler : characterization of intangible cultural heritage of folklore
(2021-11-05) Thilakarathne, S.; Gopura, S.; Payne, A.; Wickramasinghe, A.
Folklore can be identified as a collection of information compounded with creativity and reflections of a specific culture which are imparted from generation to generation via oral transmission. Folklore has played a significant role throughout history to define the emotions, lifestyle and characteristics of people in the society through narratives. A significant turning point in the antiquity of the Sinhalese nation, Sri Lanka, is the story of “Kuweni.” In folklore and folk literature, Kuweni is identified as the first female ruler of Sri Lanka. There are different mythical attributes intertwined with the narrative of Kuweni, where she has been identified as the main inducement behind the victory of the Aryan Prince Vijaya (from India) who conquered the country. There were three communities of Yakka, Naga and Deva in Sri Lanka. Kuweni who belongs to the Yakka community, betrayed her own community in order to seize power for the prince. According to the written literature of Sri Lanka, it is believed that the Sinhalese nation originated from Vijaya who captured the power of the country with the help of native Yakka princess Kuweni. Nevertheless, there are some contradictions between the folklore and literature related to the historical phenomenon around the character of Kuweni. Accordingly, the evolution of Kuweni’s character as a young woman to a lover, wife, mother and a single parent finally murdered by her own tribe can be viewed as an inquisitive narrative about power. Through examining folklore narratives, the social and cultural attributes which prevailed at the time of Kuweni reveal her emotional dilemma and her place in the symbolism of Sri Lanka. This study’s purpose is to explore how the character of Kuweni, as the first female ruler, both physically and emotionally embodies a representation of Sri Lankan intangible cultural heritage. The study reviews the literature of an expressively used mythical folklore of Kuweni through undertaking a systematic analysis of the story, drawing on two methods for examining folklore: a scientific and a social scientific approach. Using these approaches, the study reviews the character of Kuweni. This study will largely contribute to the literature of understanding folklore as an intangible cultural heritage and the study contributes to the contextual understanding of emotions, lifestyle, social attributes and power that existed during pre-historic Sri Lanka. The emotional journey of Kuweni will be studied to understand the holistic values embedded in her life. Through revitalizing the character of Kuweni, the study has implications for the contemporary creative industries of Sri Lanka, as Kuweni personifies the contemporary woman with many challenges in the life, and these may be expressed through dress and performance inspired by Kuweni. Kuweni’s emotional journey can be experienced by any woman during a certain stage of her life; therefore, she can be identified as an eternal woman.
item: Conference-Full-text
The Curse of “Kuweni”: metaphorical approach to analyze power and style of folklore
(2021-05-05) Thilakarathnea, S; Gopurab, S.; Wickramasinghec, A.; Payned, A; Boultwood, A.
Throughout the history of Sri Lanka, folklore has played a significant role in defining the characteristics and hierarchy of people in society, with power and style expressed through figurative language. This study reviews the folklore of Kuweni to shed light on how the rise and fall of power is expressed through the dress styles and adornment of ancient Sri Lanka, as described in folklore traditions. “Kuweni”, in folklore, was the first female ruler and her story represents a significant turning point of the antiquity of the Sinhalese- the Sri Lankan nation. There are different mythical characteristics intertwined with the story of Kuweni. As it unfolds, Kuweni can be identified as the main inducement behind the victory of Prince Vĳaya who conquered the country, and Kuweni betrayed her own tribe in order to seize power for the prince. It is believed that the Sinhalese nation originated from Vĳaya who captured the power of Sri Lanka with the help of native princess Kuweni. Accordingly, the evolution of Kuweni’s character from an individual woman to a lover, wife, mother and a single parent finally getting murdered by her own tribe is an intriguing narrative of cultural significance. Through analysis of literature, and a metaphorical approach to the analysis of expressively-used mythical folklore of Kuweni, this study explores the representations of her character’s power through style. Particularly, the study contributes to the contextual understanding of power and style that existed in the country at that time.
item: Conference-Full-text
Adopting distance learning in Fashion Design education : collaborative learning approach during Covid-19 pandemic
(2021-07-30) Dharmakeerthi, M.G.C.C.; Wickramasinghe, A.
There is an ongoing debate regarding the best approach to educate undergraduates in arts and design (AD) subjects through online mode due to the Covid-19 pandemic. AD students are predominantly learning through experimental and reflective learning, hence facilitating teaching, learning and assessment (TLA) activities in an online platform and maintaining an active learning environment were the identified issues of the study. The outcomes of this study will be beneficial for academia, undergraduates and service providers of online education platforms. This study targeted level two, term three undergraduates of the Bachelor of Design (Hons), Fashion Design and Product Development degree course as a group project, according to the learning outcomes defined in the curriculum. Outcomes were analyzed through mixed methodology while it was evaluated through the observations of the two examiners and post project feedback collected by students for qualitative data analysis. Quantitative analysis was done with the results obtained from summative and formative assessments of the sample of 51 students (in 12 groups). It was evident that 100% of participants were able to adapt to the online learning while the majority (90%) could virtually interact with group members in order to engage in active learning with real-time connectivity. Students’ feedback revealed that the virtual factory visits and online guest lectures were able to fill the knowledge gaps of the industry-linked project. Results of the summative assessments evidenced 8.3% of A+s while B+ has recorded as the lowest result gained by a group. In conclusion, it was observed that the possibilities of adopting the online approach were overweighing the challenges and limitations encountered as the overall results of the students are higher than the previous academic year which was conducted physically. The experimental learning was limited due to lack of materials and technical resources however it was overcome through peer group learning. Furthermore, the study has revealed that the need of TLA is to be adhering in relation to constructive alignment considering the pros and cons of distance mode teaching.
item: Conference-Full-text
Point Cloud-Based Analysis and Validation of As-Design versus As-Built Drawings
(2022-08-23) Kohulan, S; Herath, HMST; Mallikarachchi, Chinthaka
Design to build variations are common in the construction field which can result in demolition or reworks and a waste of resources. It is important to detect these variations during their early stages to minimize the consequences. Total stations, leveling equipment and measuring tapes are the conventional tools used in detecting these variations which require huge manual work and time. Usual construction activities do not offer enough time for these sorts of checks which result in a search for methods that can be automated, and which can be operated with minimum human interventions. Point cloudbased analysis is one of such methods which can be efficiently used for such purposes. The data collection and analysis can be fully or partially automated and the time required for the entire activity will be a fraction of the time spent in conventional methods. Several commercial and open-source software offers a platform to work with point clouds, but it is hard to modify the functionalities of that software as per our needs. This research focuses on using MATLAB to process synthetic point cloud data with a user-friendly GUI to achieve the research aim.
item: Conference-Full-text
Nothing is better than something – Perspective of Structural Optimization in Civil Engineering Applications
(2022-08-23) Lowhikan, S; Herath, HMST; Mallikarachchi, HMYC
Structural optimization of solids aims to find the optimal designs of structures by minimizing a constrained objective function such as the material compliance within a given problem domain. This constrained optimization problem is subjected to a set of displacement and load boundary conditions which in turn will be minimized with respect to a structural parameter. Although various structural optimization techniques have a sound mathematical basis, the practical constructability of optimal designs poses a great challenge in the manufacturing stage. The recent development in additive manufacturing partially side-steps this problem predominantly in the domain of Mechanical Engineering. However, in Civil Engineering structures, there is a great possibility of utilizing these optimization tools, especially in precast constructions. Currently, there is only a limited number of unified frameworks which output ready to manufacture parametric Computer-Aided Design (CAD) of the optimal designs. From a generative design perspective, it is essential to have a single platform that outputs a structurally optimized CAD model because CAD models are an integral part of most industrial product development and manufacturing stages. This study focuses on developing a novel unified workflow handling both topology and size optimization in a single parametric platform (Rhino-Grasshopper) which outputs a readyto-manufacture CAD model with the assessment of their structural integrity. In the proposed method, the first topology optimized pixel model is generated for any two-dimensional problem and converted into a one-pixelwide chain model using skeletonization. From the obtained skeleton, a spatial frame structure is extracted, and its members are sized optimally. Finally, the CAD model is generated using Constructive Solid Geometry (CSG) trees and its structural performance is assessed. In addition, industry-standard structural sections can be assigned to the CAD model to be analyzed and designed in accordance with standard codes of practice.
item: Conference-Full-text
A Comparative Study to Assess the Sustainability of Bamboo Reinforced Concrete over Conventional Steel Reinforced Concrete
(2022-08-23) Vitharana, TVDVK; Bandaranayake, SS; Jayasinghe, MTR; Herath, HMST; Mallikarachchi, HMYC
Amongst various sustainable building materials, bamboo reinforced concrete has come into concern as a potential substitute for steel-reinforced concrete. This has drawn attention due to some major drawbacks of steel in reinforced concrete including elevated cost, high energy consumption, increased emission of carbon, etc. Bamboo is a rapidly renewable material that has displayed outstanding mechanical properties which are adequate to replace steel in reinforced concrete. In the present context, in addition to its structural performance, it is of vital importance to evaluate the sustainability of bamboo reinforced concrete over conventional reinforced concrete. In this work, the structural capacity of replacing steel with bamboo in different structural elements was analytically determined. Subsequently, a comprehensive work study-based analysis was executed to compare the sustainability of a bamboo reinforced concrete beam element with a conventional steel-reinforced concrete beam element in terms of their embodied carbon and cost. Results of this study justify the possibility of promoting bamboo as a potentially sustainable alternative to steel in reinforced concrete as bamboo reinforced concrete displays drastically reduced sustainability indices for embodied carbon, and cost while maintaining adequate structural capacities.
item: Conference-Full-text
GPR and LiDAR Synergy: Honeycomb detection in Concrete Structures
(The Institution of Engineers, Sri Lanka, 2021-10-09) Herath, S; Subakaran, R
Honeycombs are formed due to trapped air voids around the coarse aggregates during concreting. These can form inside the concrete structures and on the surface as well. Detecting honeycomb concrete structures is essential to ensure the structural integrity and durability of the structure. However, detecting internal honeycombs are much cumbersome as it is not visible to naked eyes. Ground Penetrating Radar (GPR) is a system that emits and receives Electromagnetic waves which can penetrate through different materials and could detect any disturbances on its travel path. Using the GPR output data, we can identify the defects, honeycombs. Further, Laser imaging Detection and Ranging (LiDAR) emits and receives Laser waves to acquire surface details and reconstruct 2.5D models as Point Clouds. Each of these systems has individual drawbacks. By combining both the systems we can produce data sets that can be used to reconstruct a full 3D understanding of the structure and to conduct further analysis. This paper reviews the pros and cons of GPR and LiDAR and proposes a method on how a full 3D understanding can be obtained using both of these systems and the limitations in the real-world applications of this synergy.
item: Conference-Extended-Abstract
Gaussian process homogenisation and design of technical textiles
(2021-08-22) Herath, S; Cirak, H
A method for computational homogenisation of thin membranes is proposed to assist in the mechanical analysis of technical textiles. Conventional computational homogenisation schemes have a limited scope in analysing the complex nonlinear behaviour of textiles where the interlooped or interlaced fibres undergo large deformations. Also, the higher computational cost of the existing homogenisation schemes inspires the inception of a data-driven multiscale computational homogenisation scheme. In this paper, the efficient integration of statistical learning in computational homogenisation is proved not only to result in the efficient mechanical analysis but also to open avenues in material design of knitted and woven technical textiles.
item: Conference-Abstract
Feasibility of using 3D point cloud technologies in Sri Lankan Civil Engineering Industry
(2021-03) Subakaran, R; Herath, HMST
With the rapid advancement of technologies such as Laser Scanning and Point Cloud Data processing, the influence of these technologies in Civil Engineering Projects are inevitable. These technologies are used in various industries, including Civil Engineering, in tasks namely, 3D model preparation, Construction progress monitoring, Quality control, Virtual walk-throughs, etc. Many countries have already made the most out of these technologies whereas Sri Lanka as a developing country, seems to have lagged in implementing such tools, especially in the construction sector. Further applications of these digital technologies extend to preserve ancient monuments from disasters, create digital copies of structures, update timely variations of structures and predict the life-cycle of buildings. For instance, during renovations, the availability of any BIM models or any related drawings may be limited and renovations with destructions must be avoided; these limitations pave the way to the adaptation of non-destructive laser scanning and other related technologies. Moreover, there are significant advancements in efficient 3D point cloud data acquisition and accurate processing techniques around the globe, making it a reliable and effective solution for various civil engineering challenges. This study reviews the available technologies and their applications in the civil engineering domain and the feasibility of implementing these technologies in the Sri Lankan civil engineering industry.
item: Conference-Abstract
Simulation of deployable solar sails
(2021-02-02) Piyumi, K. W. C.; Jayasekara, L. M. M. B.; Herath, H.M.S.T.; Mallikarachchi, H. M. Y. C.
Concept of solar sailing which uses solar energy to propel a spacecraft is becoming popular as a low-cost spacecraft propulsion system, especially for high energy-consuming longrange spacecraft. To capture a sufficient amount of energy these solar sails are orders of magnitudes larger in size compared to space available in spacecraft. Moreover, these solar sails, consist of thin folded membranes supported on a backing structure made of self deployable booms. Hence these solar sails along with deployable booms will be subjected to very high compaction to store in launch vehicle for transportation. While thin membrane panels are folded by introducing a series of fold-lines, deployable booms made of thin woven fibre composites are commonly used as a backing structure in these applications. Analogous to thin membrane panels, these booms are subjected to very high compact configurations which induce high stresses and curvatures. Hence, an optimized folding mechanism for solar sails is important to fully function during the deployment without failure. Simulation of deployment behaviour of these solar sails along with booms will facilitate the identification of suitable folding mechanism and optimized designs. In this study, idealisation techniques are presented to simulate accurate solar sail deployment. First, a simulation of a selected repetitive unit cell pattern of Miura-Ori folding was performed to develop an idealization method for the intersected creases in a virtual environment. Also, the effect of membrane thickness on the deployment was studied and verified using a series of experiments. Results illustrate that the connection with rotational stiffness gives better idealisation, and the deployment force and shape have a significant influence from membrane thickness and foldline geometry. Secondly, a simulation of woven fibre composites was performed to capture the nonlinear bending behaviour which is crucial in predicting the accurate behaviour of deployable booms. The numerical model developed can capture accurate moment-curvature response, as observed in experiments, including the non-linear behaviour. This indicates that modelling techniques presented are capable of utilising for simulation of a large-scale solar sail with the backing structure to develop optimised designs.
item: Conference-Abstract
Semi-automated crack detection using computer vision
(2020) Sujeeka, N; Lowhikan, S; Mallikarachchi, HMYC
The characteristics of surface cracks reflect the health state and functional degradation level of structures. Inspection and measurement of cracks on concrete surfaces are therefore of crucial importance and considered to be a fundamental component of safety and health monitoring of concrete structures. The conventional manual tracing of crack detection is time-consuming and depended largely on the inspector’s experience and knowledge. This paper presents a novel semiautomated approach for crack detection using computer vision and image processing techniques. The proposed method requires a pre-defined length to determine the calibration factor which gives the relation between the pixels of the image and the actual scale. High-resolution images of surface cracks are captured and subsequently processed according to the proposed method to obtain accurate crack measurements. The acquired digital images are subjected to a few image pre-processing steps for noise reduction and accurate determination of crack boundaries. The study also includes a comparison of the efficiency of edge detection and segmentation techniques in crack detection. Furthermore, this approach can be easily accommodated on mobile phone platforms that simplify and accelerate the process of crack detection. Experimental results demonstrate that the established method is capable of precisely perceiving the surface crack measurements.
item: Conference-Abstract
Experimental investigation on torsional behaviour of carbon fiber reinforced polymer strengthened concrete beams curved in horizontal plane
(2020) Weerasinghe, KAB; Sajinthan, R; Gamage, JCPH
Experimentally investigated the torsional resistance of externally bonded, Carbon Fiber Reinforced Polymer(CFRP) strengthened concrete beams curved in the horizontal plane. Twelve beams with radius of curvature 2000 mm and 4000 mm were tested for different CFRP strengthening schemes which include 90°("U" wrap) and 45°(spiral) wrappings. Two beams from each radius of curvature were used as control beams. Beams with 4000 mm radius of curvature have shown percentage increases of 34.21% and 26% in torsional capacity for the 90° and 45° wrappings respectively. Percentage increases of 33.03% and 34% were observed for beams with 2000 mm radius of curvature for U and spiral wrapping schemes respectively. The failure modes observed included torsion induced tensile failure of concrete and CFRP debonding.
item: Conference-Abstract
Nonlinear material modeling and design using statistical learning
(2020) Herath, S
A method for nonlinear material modeling and design using statistical learning is proposed to assist in the mechanical analysis of structural materials. Although the extension to other materials is straightforward, the scope of this paper is limited to materials with an underlined periodic microstructure. Conventional computational homogenization schemes are proven to underperform in analyzing the complex nonlinear behavior of such microstructures with finite deformations. Also, the higher computational cost of the existing homogenization schemes inspires the inception of a data-driven multiscale computational homogenization scheme. In this paper, a statistical nonlinear homogenization scheme is discussed to mitigate these issues using the Gaussian Process Regression (GPR) statistical learning technique. In the microscale, characteristic Representative Volume Elements (RVEs) are modeled, and the macroscale deformation is homogenized using periodic boundary conditions. Next, a data-driven model is trained for different strain states of an RVE using GPR. In the macroscale, the nonlinear response of the macroscopic structure is analyzed, for which the stresses and material response are predicted by the trained GPR model. This paper produces analytically tractable expressions for all the steps taken in relation to GPR learning, proofs of accuracy in energy, stress, and stress-tangent predictions.
item: Conference-Abstract
Urban development in Sri Lanka
(1982) Mendis, W
The planning, designing and construction of towns and cities in Sri Lanka have been a continuous process for centuries. Ancient Sri Lanka boasts of magnificent cities such as Anuradhapura, Polonnaruwa, Sigiriya, and Yapahuwa. Writings of ancient, times describe the beauty and function of these cities in glowing words. It can be aptly concluded from such works that our ancient towns and cities had been designed and laid-out with the highest objectives of social and economic organisation and in keeping with the ideals of aesthetic balance. The economic role of these ancient urban settlements is clear by their very location, either around agricultural hinterlands or at sea-ports. In such a context, agriculture and trade had provided the basis of the early cities. Occupational specialisation and social development in them had been stimulated only under those conditions.
item: Conference-Abstract
Seismic performance assesment of reinforced concrete framed buildings in Sri Lanka : a case study)
Gunaratne, SKA; Lewangamage, CS
Sri Lanka is considered to be in an aseismic zone (zone 0) away from major plate boundaries or any active faults. However, the first Earthquake hazard recorded on 14th April 1615 in Colombo with about 2000 deaths and destroying 200 houses. Since then, there have been many seismic events in Sri Lanka and neighbouring areas which are small to moderate in magnitude of which the tremors were felt by the people in some of the regions in Sri Lanka. Therefore, Sri Lanka has to be considered to be situated in higher seismic zones with respect to the seismic risk for the structures. Despite the above situation in Sri Lanka, almost all the buildings have not been designed and detailed for earthquake resistance. Hence, it is high time to commence not only the design and detailing of the buildings for seismic resistance but also the seismic assessment and retrofitting of the existing important buildings. Nevertheless, detailed seismic performance assessments considering the in-situ conditions of die buildings are new to Sri Lanka. Therefore, as an initiative for such future assessments, this study appraise the applicability and importance of pushover analysis for seismic assessment of a medium rise reinforced concrete framed building having a large floor area incorporating all As-built details. Pushover analysis procedure given in ATC 40 and FEMA 356 guidelines were used to carry out the performance assessment using SAP 2000. It is found from the study that the building performs at Immediate Occupancy performance level for serviceability earthquake in seismic zone 1 (CA=0.06, Cv=0.09). In addition, found that the building can safely withstand a maximum ground motion having acceleration coefficients of Ca=0.11 and Cv=0.17 performing at Immediate Occupancy performance level. Furthermore, it concludes that the pushover procedure is applicable and realistic results can be obtained for the building considered.
item: Conference-Abstract
Simulation of low cycle fatigue with Abaqus/FEA
Karivawasam, KKGKD; Mallikarachchi1, HMYC
Low cycle fatigue is an important design consideration for large steel structures and metallic machine components. Accurate prediction of fatigue endurance is essential to design the elements subjected to fatigue. The design guidelines given in codes of practices are applicable only to simple shapes and laboratory experimental verification is costly. Therefore simulation using finite element software is becoming popular. This paper demonstrate successful coupling of Abaqus/FEA and fe-safe software in predicting the uni-axial fatigue behaviour of a stainless steel specimen. The simulated results are verified against experimental results available in literature. Sensitivity to surface roughness and material model were examined.