ORCID Profile
0000-0003-1502-5772
Current Organisation
University of Sri Jayewardenepura
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 12-2015
Publisher: Springer Singapore
Date: 19-09-2020
Publisher: Springer Science and Business Media LLC
Date: 11-2022
Publisher: No publisher found
Date: 2020
Publisher: Wiley
Date: 13-09-2022
Abstract: Manufactured sand (MS) has been started utilizing as an alternative in constructions due to the escalated demand for river sand (RS). The microfine aggregate (MFA) is a salient constituent in manufactured sand, which is a crushed reactive form of parent rocks having particles less than 0.075 mm. This paper presents the effects of varying microfine aggregate levels on bleeding, plastic shrinkage cracking (PSC) and compressive strength of MS made concrete. Two types of MS were utilized: MS from Hornblende‐Gneiss rock (MH) and MS from Charnockite rock (MC) and the MFA level was ranged from 0% to 12% at 3% increments and the reference concrete was prepared with RS alone. With the MFA levels, the bleeding of MS concretes was reduced where, at 0% MFA level the maximum bleeding rates were observed for MC (1.63 kg/m 2 ) and MH (0.84 kg/m 2 ) concretes. PSC results were analyzed from an image processing technique, which revealed an increasing trend of mean and maximum crack widths, crack length and crack area with the MFA levels. At 0% MFA, the mean crack width of MC (0.19 mm) and MH (0.17 mm) concretes manifested marginally similar to RS concrete (0.17 mm). The decreasing bleeding with the MFA levels can be attributed to the increasing severity to PSC. Moreover, the optimum 28 days compressive strength of MC (57.5 MPa) and MH (56.1 MPa) concretes was achieved at 3% MFA level which are higher than RS concrete (51.5 MPa). Consequently, the MFA level should be limited to 3% for better plastic and hardened performance of MS made concrete.
Publisher: Elsevier BV
Date: 08-2021
Publisher: Informa UK Limited
Date: 2015
Publisher: IEEE
Date: 27-07-2021
Publisher: American Chemical Society (ACS)
Date: 24-04-2022
Abstract: Vanadium dioxide (VO
Publisher: Emerald
Date: 14-07-2021
DOI: 10.1108/JSFE-10-2020-0030
Abstract: In this study, the insulation fire ratings of lightweight foamed concrete, autoclaved aerated concrete and lightweight aggregate concrete were investigated using finite element modelling. Lightweight aggregate concrete containing various aggregate types, i.e. expanded slag, pumice, expanded clay and expanded shale were studied under standard fire and hydro–carbon fire situations using validated finite element models. Results were used to derive empirical equations for determining the insulation fire ratings of lightweight concrete wall panels. It was observed that autoclaved aerated concrete and foamed lightweight concrete have better insulation fire ratings compared with lightweight aggregate concrete. Depending on the insulation fire rating requirement of 15%–30% of material saving could be achieved when lightweight aggregate concrete wall panels are replaced with the autoclaved aerated or foamed concrete wall panels. Lightweight aggregate concrete fire performance depends on the type of lightweight aggregate. Lightweight concrete with pumice aggregate showed better fire performance among the normal lightweight aggregate concretes. Material saving of 9%–14% could be obtained when pumice aggregate is used as the lightweight aggregate material. Hydrocarbon fire has shown aggressive effect during the first two hours of fire exposure hence, wall panels with lesser thickness were adversely affected. Finding of this study could be used to determine the optimum lightweight concrete wall type and the optimum thickness requirement of the wall panels for a required application.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Emerald
Date: 27-02-2023
DOI: 10.1108/JSFE-09-2022-0030
Abstract: Elevated temperature material properties are essential in predicting structural member's behavior in high-temperature exposures such as fire. Even though experimental methodologies are available to determine these properties, advanced equipment with high costs is required to perform those tests. Therefore, performing those experiments frequently is not feasible, and the development of numerical techniques is beneficial. A numerical technique is proposed in this study to determine the temperature-dependent thermal properties of the material using the fire test results based on the Artificial Neural Network (ANN)-based Finite Element (FE) model. An ANN-based FE model was developed in the Matlab program to determine the elevated temperature thermal diffusivity, thermal conductivity and the product of specific heat and density of a material. The temperature distribution obtained from fire tests is fed to the ANN-based FE model and material properties are predicted to match the temperature distribution. Elevated temperature thermal properties of normal-weight concrete (NWC), gypsum plasterboard and lightweight concrete were predicted using the developed model, and good agreement was observed with the actual material properties measured experimentally. The developed method could be utilized to determine any materials' elevated temperature material properties numerically with the adequate temperature distribution data obtained during a fire or heat transfer test. Temperature-dependent material properties are important in predicting the behavior of structural elements exposed to fire. This research study developed a numerical technique utilizing ANN theories to determine elevated temperature thermal diffusivity, thermal conductivity and product of specific heat and density. Experimental methods are available to evaluate the material properties at high temperatures. However, these testing equipment are expensive and sophisticated therefore, these equipment are not popular in laboratories causing a lack of high-temperature material properties for novel materials. However conducting a fire test to evaluate fire performance of any novel material is the common practice in the industry. ANN-based FE model developed in this study could utilize those fire testing results of the structural member (temperature distribution of the member throughout the fire tests) to predict the material's thermal properties.
Publisher: MDPI AG
Date: 07-12-2021
DOI: 10.3390/BUILDINGS11120621
Abstract: Lightweight Steel Frames (LSF) in building construction are becoming more popular due to their fast, clean, and flexible constructability. Typical LSF wall panels are made of cold-formed and thin-walled steel lipped channel studs with plasterboard linings. Due to the high thermal conductivity of steel, these LSF components must be well engineered and covered against unintended thermal bridges. Therefore, it is essential to investigate the heat transfer of the LSF wall of different configurations and reduce heat loss through walls by lowering the thermal transmittance, which would ultimately minimise the energy consumption in buildings. The effect of novel thermal insulation material, Vacuum Insulation Panels (VIP), their position on the LSF wall configuration, and Oriented Strand Board (OSB) and plasterboard’s effect on the thermal transmittance of LSF walls were investigated through numerical analysis. A total of 56 wall configurations and 112 finite element models were analysed and compared with the minimum U-value requirements of UK building regulations. Numerical model results exhibited that using plasterboards instead of OSB has no considerable effect on the U-value of the LSF walls. However, 77% (4 times) of U-value reduction was exhibited by introducing the 20 mm VIP. Moreover, the position of the VIP to the U-value of LSF was negligible. Based on the results, optimum LSF wall configurations were proposed by highlighting the construction methods. Additionally, this study, through literature, seeks to identify other areas in which additional research can be conducted to achieve the desired thermal efficiency of buildings using LSF wall systems.
Publisher: American Society of Civil Engineers (ASCE)
Date: 06-2015
Publisher: Informa UK Limited
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 11-02-2019
DOI: 10.1007/S11121-019-00997-4
Abstract: Evaluation of primary prevention and health promotion programs contributes necessary information to the evidence base for prevention programs. There is increasing demand for high-quality evaluation of program impact and effectiveness for use in public health decision making. Despite the demand for evidence and known benefits, evaluation of prevention programs can be challenging and organizations face barriers to conducting rigorous evaluation. Evaluation capacity building efforts are gaining attention in the prevention field however, there is limited knowledge about how components of the health promotion and primary prevention system (e.g., funding, administrative arrangements, and the policy environment) may facilitate or hinder this work. We sought to identify the important influences on evaluation practice within the Australian primary prevention and health promotion system. We conducted in-depth semi-structured interviews with experienced practitioners and managers (n = 40) from government and non-government organizations, and used thematic analysis to identify the main factors that impact on prevention program evaluation. Firstly, accountability and reporting requirements impacted on evaluation, especially if expectations were poorly aligned between the funding body and prevention organization. Secondly, the funding and political context was found to directly and indirectly affect the resources available and evaluation approach. Finally, it was found that participants made use of various strategies to modify the prevention system for more favorable conditions for evaluation. We highlight the opportunities to address barriers to evaluation in the prevention system, and argue that through targeted investment, there is potential for widespread gain through improved evaluation capacity.
Publisher: Springer Science and Business Media LLC
Date: 28-02-2022
Publisher: Informa UK Limited
Date: 28-10-2021
Publisher: Emerald
Date: 17-01-2022
DOI: 10.1108/JSFE-10-2021-0066
Abstract: Light-Gauge Steel Frame (LSF) structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel lipped channel sections negative fire performance, cavity insulation materials are utilized in the LSF configuration to enhance its fire performance. The applicability of lightweight concrete filling as cavity insulation in LSF and its effect on the fire performance of LSF are investigated under realistic design fire exposure, and results are compared with standard fire exposure. A Finite Element model (FEM) was developed to simulate the fire performance of Light Gauge Steel Frame (LSF) walls exposed to realistic design fires. The model was developed utilising Abaqus subroutine to incorporate temperature-dependent properties of the material based on the heating and cooling phases of the realistic design fire temperature. The developed model was validated with the available experimental results and incorporated into a parametric study to evaluate the fire performance of conventional LSF walls compared to LSF walls with lightweight concrete filling under standard and realistic fire exposures. Novel FEM was developed incorporating temperature and phase (heating and cooling) dependent material properties in simulating the fire performance of structures exposed to realistic design fires. The validated FEM was utilised in the parametric study, and results exhibited that the LSF walls with lightweight concrete have shown better fire performance under insulation and load-bearing criteria in Eurocode parametric fire exposure. Foamed Concrete (FC) of 1,000 kg/m3 density showed best fire performance among lightweight concrete filling, followed by FC of 650 kg/m3 and Autoclaved Aerated Concrete (AAC) 600 kg/m3. The developed FEM is capable of investigating the insulation and load-bearing fire ratings of LSF walls. However, with the availability of the elevated temperature mechanical properties of the LSF wall, materials developed model could be further extended to simulate the complete fire behaviour. LSF structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel-lipped channel sections negative fire performance, cavity insulation materials are utilised in the LSF configuration to enhance its fire performance. The lightweight concrete filling in LSF is a novel idea that could be practically implemented in the construction, which would enhance both fire performance and the mechanical performance of LSF walls. Limited studies have investigated the fire performance of structural elements exposed to realistic design fires. Numerical models developed in those studies have considered a similar approach as models developed to simulate standard fire exposure. However, due to the heating phase and the cooling phase of the realistic design fires, the numerical model should incorporate both temperature and phase (heating and cooling phase) dependent properties, which was incorporated in this study and validated with the experimental results. Further lightweight concrete filling in LSF is a novel technique in which fire performance was investigated in this study.
Publisher: MDPI AG
Date: 31-10-2022
DOI: 10.3390/BUILDINGS12111820
Abstract: This paper reviews the research advancements and design practices related to the structural web crippling response of lipped Cold-Formed (CF) carbon steel, stainless steel, and aluminium channels with web perforations. The web crippling response differs among each material based on the non-linear stress-strain characteristics and degree of strain hardening. Therefore, the reduction in the web crippling strength of web-perforated CF channel sections made of different materials may not be equivalent. The research activities surrounding the web crippling response of CF channels with and without web openings were reviewed initially. Despite the limited design provisions given in the international specifications for the web crippling design of lipped CF channels with web openings, web crippling studies conducted across the world have developed suitable design equations in the form of reduction factors. Past research studies have substantially captured the web crippling response of carbon steel channels with web openings while that of stainless steel and aluminium are limited, as identified in this paper. Lastly, numerical models were developed for simulating the web crippling behaviour of lipped CF carbon steel, stainless steel, and aluminium channels with web opening and validated with past experimental data, with a view for developing unified design guidelines.
Publisher: Informa UK Limited
Date: 08-11-2021
Publisher: Elsevier BV
Date: 05-2013
Location: No location found
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Chaminda Konthesingha.