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.
 Research Publications |  Thesis & Dissertation |  E- Books |
 UoM Journal Publications |  UoM Conference Proceedings |  Articles published in Scimago's Q1 journals |  UoM Research Reports |  Other Articles authored by UoM staff |
Recent Submissions
item: Conference-Extended-Abstract
Investigating the structural issues caused by telecommunication towers constructed on rooftop slabs
(Department of Civil Engineering, University of Moratuwa, 2026) Shangari, P; Damruwan, HGH; Baskaran, K; Chandrathilaka, K
Rooftop installation of telecommunication towers on existing buildings has become a common strategy for expanding network coverage in dense urban areas of Sri Lanka. However, many existing structures were not originally designed to support the additional loads imposed by such installations, raising concerns regarding structural integrity and long-term durability. This study systematically investigates the structural and durability issues associated with rooftop telecommunication tower installations through field investigations across twelve sites, finite element modelling of a representative case study, and manual calculations per Eurocode standards. Field inspections revealed prevalent durability problems including water leakage, concrete spalling, and exposed reinforcement, though major structural failures were not observed. However, finite element analysis under ultimate limit state loading indicated that the host structure lacks adequate reserve capacity, with critical beams exhibiting insufficient flexural and shear reinforcement, meaning that visible condition alone is not a reliable indicator of ultimate safety. This research identifies systemic gaps in current installation practices and recommends amendments to strengthen structural verification, durability requirements, and regulatory enforcement for rooftop tower installations.
item: Conference-Extended-Abstract
Experimental mechanical characterisation of selected Sri Lankan hardwood timber species for local structural timber design applications with reference to EN 338
(Department of Civil Engineering, University of Moratuwa, 2026) De Silva, MVY; Chandrathilaka, K; Chandrathilaka, K
Timber is a renewable structural material, but Sri Lankan design practice often relies on properties developed for foreign species and strength classes. This study established a preliminary local dataset for Hora, Jak, Mahogany and Teak and compared their behavior with values commonly adopted from EN 338. Fifty-three small clear specimens were tested in four-point bending, tension parallel to grain, compression parallel to grain and compression perpendicular to grain. Moisture content and density were also measured. Clear differences occurred between species and loading directions. Teak had the highest density and bending stiffness, Hora the greatest bending strength, Mahogany the highest tensile strength, and Jak the highest moisture-normalised compression strength parallel to grain. Compression perpendicular to grain was far lower than longitudinal compression for all species tested in that mode, confirming the need for separate bearing and support zone checks. The measured mean properties showed different relationships with EN 338 benchmarks across the loading modes, indicating that a single reference class does not consistently represent all measured properties of these local hardwoods. The reported values are preliminary sample means rather than characteristic design values. The dataset supports the development of a nationally verified timber property database, although larger samples and full-size graded-member testing are required before formal strength classes can be proposed.
item: Conference-Extended-Abstract
Buckling behaviour of cold-formed steel z-sections under axial compression and bi-axial bending
(Department of Civil Engineering, University of Moratuwa, 2026) Senaratne, LADT; Prabasha, K; Herath, S; Chandrathilaka, K
Cold-formed steel (CFS) Z-sections are widely used as purlins, girts, and secondary framing members, yet their response becomes complex when axial compression acts together with bending about both principal axes. This study investigates the buckling capacity and failure behaviour of Z-section members under concentric and eccentric compression and evaluates the influence of member geometry and web perforations. Material properties were established from tensile coupon tests, after which four 500 mm non-perforated specimens were tested under axial, major-axis eccentric, minor-axis eccentric, and bi-axial loading. Finite element models were developed in ABAQUS and were validated against the experimental results. The validated model was then used to quantify the influence of member length, section thickness, and web opening diameter. Parametric analyses showed that increasing member length from 500 mm to 1500 mm reduced capacity by approximately 14% under pure compression and by 27% and 37% for bi-axial eccentricities of 20 mm by 20 mm and 40 mm by 40 mm, respectively; increasing section thickness from 1.96 mm to 3.00 mm enhanced capacity by approximately 76–82%, whereas a 40 mm web perforation reduced capacity by approximately 4–6%. The results demonstrate that eccentricity, slenderness, section thickness, and opening size are important parameters governing the stability of CFS Z-section beam-columns and provide a validated basis for further design-oriented studies.
item: Conference-Extended-Abstract
Experimental investigation on geometric, physical and mechanical properties of dendrocalamus giganteus in Sri Lanka
(Department of Civil Engineering, University of Moratuwa, 2026) Thathsarani, MN; Fernando, PLN; Herath, HMST; Chandrathilaka, K
Bamboo is a fast-growing, low-carbon material with strong potential for sustainable construction, yet its structural use in Sri Lanka remains limited by the absence of speciesspecific engineering data. This study experimentally characterised the geometric, physical and mechanical properties of Dendrocalamus giganteus to assess its potential for structural applications. Mature culms harvested from Balangoda were evaluated using international bamboo grading and testing procedures. Geometric properties, including external diameter, wall thickness, taper, bow, ovality and internodal length, were measured on 188 culm sections. Basic density, linear mass, compression, tension and shear parallel to the fibres, and tension perpendicular to the fibres were also determined. Moisture contents of specimens in all mechanical test series ranged from 9 to 15 percent at testing. The mean external diameter and wall thickness were 157 mm and 10.8 mm, respectively, while mean basic density was approximately 662 kg/m³. Mean compressive, tensile and shear strengths parallel to the fibres were 46.85 MPa, 153.04 MPa and 8.47 MPa, respectively. Tensile strength perpendicular to the fibres was substantially lower at 1.75 MPa, indicating susceptibility to longitudinal splitting. The findings establish a first-stage engineering property dataset for the sampled material and support further structural assessment, while highlighting the need for additional tensile testing and careful detailing against splitting. Application requires consideration of sampling limitations and material variability, together with appropriate derivation of design values.
item: Conference-Extended-Abstract
Residual compressive performance of low-carbon masonry units after a standard single-face fire
(Department of Civil Engineering, University of Moratuwa, 2026) Jayasinghe, C; Erandi, I; Dehipitiya, NN; Chandrathilaka, K
Low-embodied-energy masonry such as CSEB, AAC and EPS blocks is displacing fired clay and dense cement units in tropical construction, yet what remains of these units after a building fire is poorly quantified. Existing data come almost entirely from furnaces that heat every face uniformly, unlike a wall exposed on one side only. This study compared four traditional and four alternative unit types under a gas-fired exposure tracking the ISO 834 standard curve to a peak exposed-face temperature of 600 degrees Celsius. Specimens were oven-dried to constant mass, insulated on every face except one to enforce one-dimensional heat flow, cooled in the furnace and then loaded to failure in compression. Fired clay gained capacity, reaching 138 percent of its unheated strength through secondary sintering, while every other unit lost between 11 and 24 percent. Retention followed continuity of the cross-section rather than material category, hollow units losing about twice as much as their solid counterparts. Three of the four alternatives fell below the minimum strengths of the relevant Sri Lanka Standards, showing that selection on embodied energy grounds must be paired with a post-fire capacity check.