Browsing by Author "Thamboo, JA"

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    item: Conference-Full-text
    Development of an effective 3D mapping technique for heritage structures
    (Institute of Electrical and Electronics Engineers, Inc., 2021-09) Mahinda, MCP; Udhyani, HPAJ; Alahakoon, PMK; Kumara, WGCW; Hinas, MNA; Thamboo, JA; Abeykoon, AMHS; Velmanickam, L
    Historical buildings and structures are import ant fora country and the world since they are the only living evidence of the engineering technology of man kind. Therefore, itis of utmost importance to protect and preserve them to safe guard the identity of the particular civilizations,retain the ircultural significance, and ensure the inaccessibility to present and future generations. Since many historic structures are in a partially dilapidated state, to prevent further deterioration,itis essential to record their present status in structural engineering and building material aspects. This is typically a costly,time-demanding, unsafe, and challenging task. As a solution,3 Dgeomatics technologies, and UAVsystemsarenowbeingusedintheworldtodocument existing structures,especially in difficult-to-accessare as.This is also usually a high-cost task.In this research, an effective technique for generating structural information of anexisting building or as imilarstructure to preserve the detail so for duplicating as a truereplicais developed.The developed solution is are mote-controllable custom-made drone system with a GoPro Hero7camera.Different type so fstructures were selected, and after running several test cases,the most suitable image- taking technique and the processing plat form were identified. The effecting factors to the accuracy such as the number of images taken,and overl appercentage of images were identified and their optimum contri bution detected.As a result,the proposed solution abled to yield a dimensional accuracy of 98.9%.This study concludes that the developed effective solution is avalid alternative to high-cost3Dmappingtechniques.
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    item: Thesis-Full-text
    Seismic vulnerability assessment of masonry infilled reinforced concrete school building frames in Sri Lanka
    (2022) Sathurshan, M; Mallikarachchi, HMYC; Thamboo, JA; Wijesundara, KK
    Sri Lanka is considered as an aseismic country, hence the seismic risk is not explicitly considered in the planning and designing of critical structures. However, current studies indicate that the seismic risk cannot be completely omitted when designing buildings in Sri Lanka, particularly post-disaster structures like schools and hospitals that should be designed to withstand any potential seismic action. Meanwhile, assessing the seismic risk of all the critical structures in depth across Sri Lanka might not be an easy task, and therefore, the creation of a rapid assessment method would help to effectively screen the buildings which are seismically vulnerable. Therefore, in this study, an attempt was made to assess the seismic vulnerability of school buildings in Sri Lanka in detail by incorporating possible variations and proposing an alternate Rapid Visual Screening method (RVS) for Sri Lankan conditions by incorporating FEMA P-154 guidance. In order to study the existing school building typologies, detailed structural surveys were carried out across Sri Lanka in selected school buildings. The survey revealed that school buildings in Sri Lanka can be characterised as reinforced concrete (RC) frames, infilled with unreinforced masonry walls (MI). Based on the structural configurations, mainly two building typologies were found as (1) Type 01 and (2) Type 02. Nonetheless, in terms of MI arrangements, it was observed that significant variations exist among the school buildings. Therefore, those variabilities were explicitly taken to assess the seismic performance of MI-RC school buildings. The seismic performance of the school buildings was analysed using the OpenSees (OS) finite element programme. The torsional effects and post-processing as shear capacity and stochastic material properties (concrete, steel, and masonry) from Monte-Carlo simulation were incorporated in this study. The modal analysis and non-linear static pushover analysis were carried out, in which a total of 640 building cases were analysed. The analyses of pushover (PO) and seismic fragility revealed that the Type 02 buildings exhibit significantly better performance than the Type 01 buildings. Also, the variation in MI arrangements significantly influences the seismic resistance of the buildings. In addition, the application of the proposed RVS method is effective to carry out the seismic screening method of school buildings in Sri Lanka. Keywords: School buildings, Non-linear static pushover, Seismic performance assessment, Seismic Fragility assessment and Rapid visual screening method
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    item: Conference-Full-text
    Thin bed masonry system: review and future prospects
    (2013-11-26) Thamboo, JA; Dhanasekar, M; Yan, C
    Masonry is one of the most ancient construction materials in the World. When compared to other civil engineering practices, masonry construction is highly labour intensive, which can affect the quality and productivity adversely. With a view to improving quality and in light of the limited skilled labour in the recent times several innovative masonry construction methods such as the dry stack and the thin bed masonry have been developed. This paper focuses on the thin bed masonry system, which is used in many parts of Europe. Thin bed masonry system utilises thin layer of polymer modified mortars connecting the accurately dimensioned and/or interlockable units. This assembly process has the potential for automated panelised construction system in the industry setting or being adopted in the site using less skilled labour, without sacrificing the quality. This is because unlike the conventional masonry construction, the thin bed technology uses thinner mortar (or glue) layer which can be controlled easily through some novel methods described in this paper. Structurally, reduction in the thickness of the mortar joint has beneficial effects; for example it increases the compressive strength of masonry; in addition polymer added glue mortar enhances lateral load capacity relative to conventional masonry. This paper reviews the details of the recent research outcomes on the structural characteristics and construction practices of thin bed masonry. Finally the suitability of thin bed masonry in developing countries where masonry remains as the most common material for residential building construction is discussed.