Faculty of Engineering
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Publication Embargo Infill Masonry Strut Models in Reinforced Concrete Frames: Multilevel Reliability Analyses for Predicting In-Plane Responses(John Wiley and Sons Inc, 2026-03-10) Raheem, S; Thamboo, J; Mallikarachi, C; Wijesundara, K; Dias, PThe moment-resisting reinforced concrete (RC) frame infilled with masonry walls is a common form of construction for low- to medium-rise buildings. The importance of considering the infill masonry walls (IMW) in seismic analysis is accentuated due to the interaction between infills and the surrounding frame. Several analytical IMW models have been proposed to model IMW as equivalent diagonal struts, and the appropriateness of those models has been justified through experimental and numerical calibrations. However, the reliability of those analytical models is not well substantiated. Therefore, the reliabilities of five different analytical models have been evaluated herein using the First-Order Reliability Method (FORM). The stochastic uncertainties involved in predicting the in-plane capacities of IMW-RC frames have been incorporated in the reliability analyses. Subsequently, reliabilities of IMW models have been ascertained using experimental data sets compiled at two different scales, namely (1) single story–single bay and (2) multistory IMW-RC frames. 120 experimental data sets of single story–single bay IMW-RC frames tested under in-plane loading and three multistory IMW-RC frames tested on shake-tables were used to assess the reliabilities of IMW models. The results showed that the IMW models considered have predicted the in-plane behavior of IMW-RC frames (single or multistory) to certain levels of accuracy. The predicted reliability indices (β values) of the models vary between 1.03 and 4.13. The reliabilities differ when different aspects of the predictions are being considered, such as peak or ultimate load and drift capacities of single story–single bay frames or base shear and story drift of multistory frames. Therefore, depending on the requirement (strength- or displacement-based design), the IMW models should be selected appropriately to carry out the seismic analyses of IMW-RC buildings.Publication Open Access A cross-category analysis of high impact low occurrence (HILO) disasters(Elsevier Ltd, 2026-03-19) Samaraweera, U; Kulatunga, U; Dias, PThis paper explores six High Impact Low Occurrence (HILO) disasters, generating insights from five different categories associated with them, namely causes (geophysical, technological, biological, sociological), phases (preparedness, response, recovery), dimensions (socio-economics, governance, equity), sectors (health, education, infrastructure, economy) and national contexts with differing levels of economic development. The process involved the generation of a questionnaire, based on a literature review; and the subsequent analysis and discussion of the questionnaire responses made by six experts nominated by six academies of science in Asia. The findings highlight the limitations of probabilistic, frequency-based risk models for HILO disasters and instead emphasise the importance of scenario-based (worst-case) analyses; mechanisms that preserve inter‐generational knowledge, institutional continuity and community‐based early‐response networks; strengthening community resilience while ensuring equity; and making appropriate investments for increasing preparedness, if not through structural interventions, at least through sustained awareness programs and periodic drills. Theoretical contributions include arguments that institutional capacity, governance quality, and social resilience are more decisive determinants of HILO event outcomes than probabilistic risk analyses; and that effective preparedness depends more on anticipatory planning, scenario-based training and institutionalised memory rather than experiential learning; thus advancing HILO theory beyond event-centred and frequency-driven interpretations towards a more governance- and resilience-oriented understanding.Publication Embargo Long-term recovery from the 2004 Indian ocean tsunami in two Sri Lankan east coast municipalities(Elsevier Ltd, 2026-01) Thamboo, J; Josiah, R; Saja, A; Salah, P; Rossetto, T; Dias, PSri Lanka was the second most affected country after Indonesia, in the 2004 Boxing Day Indian Ocean tsunami (IOT). A study mission was therefore carried out twenty years after the 2004 IOT to assess the recovery of the affected regions, especially in the Eastern region of Sri Lanka, focusing on two of the most affected municipalities, i.e. Kalmunai and Batticaloa. The social and infrastructure characteristics of resettlements/relocations/new settlements in the affected regions, presence of critical infrastructure, preparedness and early warning systems installed have been assessed. It was observed that similar approaches have been adopted to plan the community relocation in both of these municipalities, while the significant reemergence of residential and commercial developments in the coastal stretches of Kalmunai municipality have been noted. Exposure analyses have revealed that there are still some critical infrastructure situated in the tsunami hazard zones. It can be construed that these municipalities have recovered from the physical losses incurred, and spatial planning is in place for future developments considering the tsunami risk. Challenges and opportunities from their differing geographical contexts appear to have been judiciously handled. However, shortcomings are noted in actual implementation due to various reasons, such as limited resources, availability of funding and preference of communities to live close to their original lands. Improving the resilience of infrastructure by designing against the expected tsunami hazard and multi-hazards, regular verification of the early warning systems and evacuation procedures are emphasized to mitigate the impacts from future tsunami.Publication Embargo Resilience of masonry infilled reinforced concrete school buildings in low to moderate seismic regions: case study of Sri Lankan schools(Springer Science and Business Media, 2025-12-08) Raheem, S; Thamboo, J; Mallikarachi, C; Wijesundara, K; Dias, PThe resilience of school buildings in high seismic regions is widely emphasised and evaluated. However such resilience in low-to-medium seismic regions are generally overlooked due to the lower probability of occurrence and low-to-medium intensities expected. Nonetheless, nominal seismic provisions should be provided for the life safety of pupils occupying these school buildings. Therefore, this study was focused on assessing the level of seismic resilience of school buildings in low-to-medium seismic regions, where the archetypal school buildings in Sri Lanka and the seismic demand in the country were taken as the case study. A framework to quantify resilience, incorporating social recovery aspects, was adopted to evaluate the seismic resilience. The resilience of the same archetypal school buildings subjected to different nominal retrofitting methods was also assessed to verify the improvement in resilience compared to un-retrofitted buildings. The epistemic and aleatory uncertainties were incorporated by using 25 different recorded seismic accelerograms and Monte-Carlo simulation of material properties (twenty sets of randomised values), respectively; with 500 combinations (aleatoric and epistemic) being analysed for each building type considered. Seismic resilience indices (RIs) obtained indicate that the school buildings with retrofitted configurations are certainly better than un-retrofitted ones, especially for higher hazard levels. Increases in the RIs are in the range of 36.6–91.2% for the highest hazard level. Sensitivity analyses were also carried out to ascertain parameter influence on RIs. The proposed nominal retrofitting solutions for these school building archetypes generate adequate resilience against the seismic hazards demarcated for the country.