Browsing by Author "Rodrigo, MNN"

Now showing 1 - 12 of 12

item: Conference-Full-text
Brownfield redevelopment: a dual currency analysis of soil stabilisation methods
(Ceylon Institute of Builders, 2018-06) Brown, L; Perera, S; Rodrigo, MNN; Sandanayake, YG; Gunatilake, S; Waidyasekara, KGAS
Evidence of climate change, such as rising sea levels and higher average temperatures, has made society become increasingly carbon conscious in recent years. Therefore, carbon estimating is becoming prominent and this research explores methods of quantifying embodied carbon of different soil stabilisation methods. This research aims at evaluating the different methods of soil stabilisation for the remediation of previously developed, brownfield sites, using a dual currency approach of investigating both cost and carbon. Therefore, the effect of using different cementitious binders such as Pulverised Fuel Ash (PFA) and Ground Granulated Blastfurnace Slag (GGBS), in lieu of Ordinary Portland Cement (OPC) was investigated. Primary data, in the form of Bills of Quantities, was collected from a civil engineering contractor who has extensive experience in the land remediation sector in the UK. This enabled cost and carbon rates to be applied to the work items, to estimate in terms of cost and carbon inputs. This data was analysed using descriptive statistics to investigate if there is a correlation between cost and carbon inputs. The study revealed that to stabilise soil, soil matrix changes from one binder to another, whereas a higher content of GGBS and PFA to lime in the alternative methods than there is for OPC. In lieu of OPC and PFA, GGBS was identified as the most cost effective and lowest carbon emitting cementitious binder. However, though PFA also signified a carbon saving, PFA was comparatively costly. Further, a perfectly positive correlation lies between the mean elemental unit rates for costs and carbon.
item: Conference-Abstract
Criteria to be used in determining project duration of road rehabilitation projects in Sri Lanka
Gunasekara, RGDH; Perera, BAKS; Rodrigo, MNN
Project duration is one of the critical features of a construction project which is determined by project planners during pre-tendering stages. Although there are several project forecasting techniques that are being practiced globally, in Sri Lanka it is the experience and practice that are used to determine the duration of a road rehabilitation project. Hence this research was aimed at developing criteria to determine the time of completion of road rehabilitation projects in Sri Lanka. Initially, a literature synthesis was carried out to identify project duration forecasting methods that are currently available and factors that can affect project durations. Subsequently, the extent of usage of those methods and factors, were determined through interviews. The main criteria were divided into four sub-criteria as relating to project scope, project complexity, project environment and management attributes. Based on the findings, ‗Unrealistic contract durations imposed by the client‘ was found to be the most critical delay factor. Project scope related criteria were the most critical factors that could affect the duration of a road rehabilitation project in Sri Lanka. Thus, it is recommended to use proper methods or criteria to determine project durations of road rehabilitation projects in Sri Lanka.
item: Conference-Full-text
Eestablishing a framework for the earned value management approach in large scale building projects
(2017) Wickramasooriya, KJ; Perera, BAKS; Rodrigo, MNN
Earned Value Management (EVM) was introduced as a powerful project control mechanism to make projects move towards their success. As sophisticated large scale building construction work is now being undertaken in Sri Lanka, the development of an EVM framework can be made a key to project success. Hence, this research was aimed at developing a framework for adopting the EVM approach in large scale building projects. EVM principles that are applicable throughout the project management cycle were identified from a literature review. Eight expert interviews were thereafter conducted to identify the current practices of EVM in Sri Lanka, barriers that impede the implementation of EVM and solutions that will mitigate those barriers. A questionnaire survey was also carried out to identify the significance of the barriers that impede the implementation of EVM in Sri Lanka and the degree of importance of the various solutions that can mitigate those barriers. Findings revealed that though the basic principles of EVM are known by almost all users, most of them do not want to rely on EVM. The lack of awareness about EVM was identified as the most significant barrier that impedes the implementation of EVM. The most important solution that could be adopted to mitigate this barrier is to conduct training sessions on the EVM approach for those from the top to the bottom of the organization concerned. A framework for the EVM approach in large scale building projects was developed ultimately.
item: Conference-Full-text
Embracing adaptive re-use of buildings: the case of Sri Lanka
(Ceylon Institute of Builders, 2017-06) De Silva, GDR; Perera, BAKS; Rodrigo, MNN; Sandanayake, YG; Ramachandra, T; Gunatilake, S
Because of land scarcity, the ever-increasing demand for new constructions has caused a grave crisis in the construction industry. This has led to the inevitable demolition of the existing building stock. In many cities, there are malfunctioning or abandoned ancient buildings situated mostly in commercially significant locations. These buildings which narrate the evolution of their cities have become important, either for historical reasons or because of their cultural heritage. For any country, its existing building stock will be of significant economic, physical and socio-cultural value. Adaptive Re-use of Buildings (ARB) is the best option available to make optimum use of the existing stock. Developing countries still have not appropriately embraced this concept as in developed countries. Thus, the objectives of this research were to identify the key parameters, benefits, barriers and challenges related to ARB in Sri Lanka. A qualitative research approach was adopted to achieve this aim by conducting expert interviews on five case studies and semi-structured interviews involving 15 local expert professionals already practicing ARB to validate the expert interview findings. Content analysis was used to analyze the findings. Physical, social and economic considerations, building codes, regulations, lack of awareness on adaptive re-use opportunities and the scarcity of material and skilled tradesmen were identified to be the most frequently encountered barriers among which were further categorized under five major groups.
item: Article-Full-text
Impact of differing site conditions on construction projects
(American Society of Civil Engineers, 2018) Amarasekara, WDL; Perera, BAKS; Rodrigo, MNN
The construction industry plays a very important role in the economy of any country. One of the major risks faced by construction projects is connected with the physical obstructions or changed conditions encountered during the execution of those projects. A condition that a contractor experiences on the site that differs materially from any of the conditions indicated in the contract he has entered into with the owner of the project or from what can be normally expected on the site is called a Differing Site Condition (DSC). The clauses that are commonly used in construction contracts in Sri Lanka when referring to DSCs are based on the FIDIC Conditions of Contract and ICTAD Standard Bidding Documents (SBDs). DSCs can lead to project delays and cost overruns in projects because they would have been unexpected and unforeseeable by the contractor at the time of bidding. Hence, this research was aimed at identifying the impact of DSCs on construction projects in Sri Lanka and the strategies that will be used to better manage those impacts. To achieve this aim, an extensive literature review was first carried out. Thereafter, ten (10) expert interviews were conducted to validate the relevance of the identified information to Sri Lanka. Commercial software was used to analyze the expert interview findings. Findings refined by the expert interviews were subsequently included in the questionnaire survey which had a response rate of 74% with 69 out of 93 responding. Relative importance index and descriptive statistics were used to analyze the data gathered through the questionnaire survey. The impact of DSCs on project cost is found to be average, whereas their impact on project duration is found to be high. The research also identified the impact of DSCs on construction projects based on their contract type, resulting impact of DSCs on traditional lump sum contracts being higher than that on either design and build contracts or traditional measure and pay contracts. The most significant cost and time related factors associated with DSCs and the strategies most suitable to manage the effects of DSCs were identified by analyzing the questionnaire survey findings. Cost to work through the DSC encountered was ranked as the most significant cost related factor out of the six factors identified, whereas Time delay due to stop of work at the site until further decisions are made was placed as the most significant time related factor out of the seven factors identified. The most suitable strategy that was identified is to get the parties to the contract to refer to all the documents related to site conditions. The research also recommends several other strategies identified according to their levels of significance.
item: Conference-Full-text
Impact of fly-ash on carbon emissions in different concrete grades
Paino, J; Perera, S; Alashwal, A; Rodrigo, MNN
Concrete is one of the most used construction materials; however, it contributes to about 7% of all carbon emissions. Various supplementary cementitious materials such as flyash have been considered to enhance concrete performance. There is a limitation of studies that address the influence of fly-ash on carbon reduction in different grades of concrete. Hence, the aim of this study is to analyse the impacts of fly-ash in concrete on carbon emissions in construction projects. A comparison between carbon emissions of portland cement concrete projects and fly-ash concrete projects was conducted using data collected from 20 construction projects in New South Wales, Australia. The results showed that higher the grade of concrete used, higher the carbon dioxide emissions, due to the increase of portland cement needed to achieve the higher grades of concrete. Introducing fly-ash to the concrete mix showed a significant reduction in carbon emissions. However, from the financial perspective, it was found that the rate per cubic metre of fly-ash concrete is 2.1% more expensive than standard concrete mixes. Therefore, the idea of adopting fly-ash into the concrete mix may not deliver cost savings as expected. Overall, this study provided clear insight into the effects of concrete usage on the environment and ways to reduce carbon emission.
item: Conference-Full-text
Introduction of a systematic process for building control in Sri Lanka
(Ceylon Institute of Builders, 2017-06) Fernando, WNL; Perera, BAKS; Rodrigo, MNN; Sandanayake, YG; Ramachandra, T; Gunatilake, S
Building Control (BC) contributes significantly to the national economy as well as to the social wellbeing of the public of a country by ensuring the quality of its buildings and their health and safety, structural stability and energy efficiency and by imposing building rules and regulations related to the construction industry of the country. Building work must be properly regulated and monitored by the local authorities during the Plan Approval Process (PAP) by strictly adhering to the relevant building rules and regulations. However, BC in Sri Lanka is fragmented and not well managed due to the low involvement of professionals in the building work and poor supervision of building plan submissions and other related tasks. This condition has led to corruption and malpractices. Therefore, there is a vital need for professionals to get involved in the field, if the existing practises in Sri Lanka are to be changed. The aim of the research was to propose a suitable mechanism for building control in Sri Lanka which will have the involvement of professionals of the country. The effectiveness of the existing system was ascertained through the research objectives. A qualitative research approach was adopted to achieve the research aim through semi structured interviews conducted with 15 professionals coming under five categories. Content analysis was used to analyse the findings and to finally propose a suitable mechanism for building PAP by considering the existing process, identifying the weaknesses in the local practices so that the unfavourable impacts on the current PAP in Sri Lanka could be reduced and corruption and malpractices mitigated.
item: Conference-Full-text
Selection of nominated subcontractors in commercial building construction in Sri Lanka
(IEEE, 2016-05) Rodrigo, MNN; Perera, BAKS; Jayasekara, AGBP; Bandara, HMND; Amarasinghe, YWR
The construction industry comprises of numerous Nominated Subcontractors (NSCs) employed in various projects. Besides, plentiful NSCs enter into the industry due to ease of entry. However, all NSCs might not possess the required expertise to fulfill client’s requirements. Thus, various issues have aroused due to improper selection of NSCs creating selection of NSCs vital. The study comprised of interviews and questionnaire survey to derive at the aim of this research. Besides, to understand and compare nominated subcontracting practices between Sri Lanka and other countries, a literature synthesis followed by interview and questionnaire survey were executed. The issues aroused due to improper selection and solutions to avoid them were identified through the literature synthesis; validated through the interviews; ranked through the questionnaire survey. On a positive note, selection method of NSC; subcontract signed between Main Contractor (MC) and NSC are used in Sri Lanka equalizing the nominated subcontracting practices in other countries. However, there is no form of subcontract prepared for Sri Lankan usage; no compulsory subcontractor registration procedure in Sri Lanka. Further, the most critical issue due to improper selection of NSC, is delays occurred by NSC. Moreover, NSC’s program being in line with MC’s program was recognized as the most important solution to avoid this issue. Hence, these solutions assist to avoid the occurrence of issues related to selection enabling proper selection of nominated subcontracting practices.
item: Article-Full-text
Suitability of public-private-partnership procurement method for road projects in Sri Lanka
(Emerald Group Publishing Limited, 2019) Dabarera, GKM; Perera, PAKS; Rodrigo, MNN
Purpose – Governments of many developing countries that are unable to develop their infrastructure in order to obtain financial resources prefer to establish public–private partnerships (PPPs) for providing the much-required infrastructure. Time is thus opportune for Sri Lanka, which is also a developing country, to make use of PPPs to develop its road network. The purpose of this paper is, therefore, to identify the PPP models that suit road construction in Sri Lanka. Design/methodology/approach – The study used a mixed approach. The characteristics of road construction, procurement selection factors to be considered in road construction, and the different PPP models that can be used for such procurements were identified through a comprehensive literature synthesis. The findings were validated using expert interviews. A questionnaire survey identified the PPP models that suit road construction in Sri Lanka. The most suitable model among them was identified by ranking the PPP models using procurement selection factors. Findings – Build–Own–Operate–Transfer was identified as the PPP model that best suits road construction in Sri Lanka. However, investors may not find it attractive because of its high payback period, a result of the low traffic volume in Sri Lanka. Therefore, a PPP model that involves road construction alone will not be feasible in Sri Lanka. It will have to include the construction of other infrastructure as well. Originality/value – The study identifies a PPP model that best suits the road construction projects in Sri Lanka.
item: Conference-Full-text
Synergy between blockchain and circular economy in improving construction waste management: a literature review
(Ceylon Institute of Builders - Sri Lanka, 2023-07-21) Jayarathna, HSNM; Perera, BAKS; Atapattu, AMDS; Rodrigo, MNN
The inverse relationship between the development of the construction sector and the preservation of the ecosphere is highly manifested by the excessive waste products resulting from the construction processes that are irrepressible by the existing waste management practices. Research has been conducted on utilising smart technologies such as blockchain technology and modern concepts such as the circular economy (CE) in enlightening waste management practices. Yet, the applicability of intervening the synergy of the two concepts of “blockchain-circular economy” is not adequately addressed in the existing literature from the perspective of effective construction waste management. Therefore, this study aimed at identifying the applicability of blockchain technology and circular economy in enhancing the effectiveness of construction waste management. Accordingly, a comprehensive literature review was conducted on the existing research on the enablers, barriers and strategies for the integration of the blockchain-circular economy, blockchain-waste management, and circular economy-waste management. The collected data were analysed using content analysis. The findings suggested that enablers such as supportive legislations and sustainability increments, barriers such as risks and lack of knowledge, and strategies such as introducing regulatory standards and adaption to technologies are common for the integration of the concepts. Accordingly, this study reveals the potential of assessing the practicability of integrating blockchain, circular economy and waste management in a common platform to establish resource optimisation in the construction sector.
item: Conference-Abstract
Thermal comfort in air conditioned office environments in Colombo, Sri Lanka.
(IEEE, 2017-05) Rodrigo, GA; Perera, BAKS; Rodrigo, MNN; Jayasekara, AGBP; Amarasinghe, YWR
Thermal comfort in office environments is of prime importance as it is directly correlated to the productivity of its occupants. ASHRAE Standard 55 is a prominently used thermal comfort standard across the world. However many industry experts question the applicability of the ASHRAE Standard 55 for tropical regions. The research findings revealed that majority of occupants were dissatisfied of the ASHRAE Standard 55.
item: Conference-Abstract
Thermal comfort in air conditioned office environments in Colombo, Sri Lanka.
(2017) Rodrigo, GA; Perera, BAKS; Rodrigo, MNN
Thermal comfort in office environments is of prime importance as it is directly correlated to the productivity of its occupants. ASHRAE Standard 55 is a prominently used thermal comfort standard across the world. However many industry experts question the applicability of the ASHRAE Standard 55 for tropical regions. The research findings revealed that majority of occupants were dissatisfied of the ASHRAE Standard 55.