Increase of the ambient air temperature in cities caused by the urban heat island phenomenon has a seri- ous impact on the economic and social system of cities. to counterbalance the consequences of the increased urban temperatures important research has been carried out resulting in the development of efficient mitigation technologies. the present paper aims to present the state of the art in terms of local climate change and urban heat island mitigation techniques. In particular, developments in the field on highly reflective materials, cool and green roofs, cool pavements, urban green and of other mitigation technologies are presented in detail, while examples of implemented projects are given.
The paper presents risk assessment of construction projects. The assessment is based on the multi‐attribute decision‐making methods. The risk evaluation attributes are selected taking into consideration the interests and goals of the stakeholders as well as factors that have influence on the construction process efficiency and real estate value. Ranking of objects and determination of their optimality are determined by applying TOPSIS grey and COPRAS‐G methods with attributes values determined at intervals. A background and a description of the proposed model are provided and key findings of the analysis are presented. Santrauka Straipsnyje vertinama statybos projektu rizika. Vertinimas pagristas ivairiais daugiatikslio vertinimo metodais. Rizikos vertinimo rodikliai atrenkami, atsižvelgiant i suinteresuotu šaliu interesus, tikslus ir veiksnius, kurie turi itakos statybos proceso efektyvumui ir nekilnojamojo turto vertes didinimui. Projektai surikiuoti pagal naudinguma, nustatyti santykiniai ju optimalumo dydžiai. Uždavinio modeliui aprašyti ir jam išspresti taikomi TOPSIS grey ir COPRAS‐G metodai. Projektu savybes aprašomos efektyvumo rodikliu reikšmemis, apibrežiamomis intervaluose. Straipsnyje aprašomas taikomas modelis, atlikta uždavinio analize ir pateikiamos trumpos išvados. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: sprendimu priemimas, statyba, rizika, ivertinimas, rodikliai, TOPSIS grey, COPRAS‐G, rangavimas
The paper deals with the location selection problem of the garage at the parcel of a single-family residential house. The mathematical model for this real life problem is constructed within MCDM framework. The significance of the chosen criteria was evaluated by AHP approach. The formulated MCDM problem is solved applying WASPAS extension, namely WASPAS-SVNS. The applied single-valued neutrosophic set allows to modeling uncertainty of the initial information explicitly. A numerical example is considered in order to verify the proposed approach.
The Delphi method has been used as a main research method by a growing number of researchers in the Construction Engineering and Management (CEM) field in the past two decades. Although a number of studies are available on the use of Delphi, few researchers fully examine the potential of the Delphi method in the combined use of statistical techniques, which is an inevitable trend for future Delphi research. This paper aims to review the combined use of Delphi and other quantitative methods in the CEM field based on a structured literature review of 88 relevant papers. All of the 88 papers are systematically identified from ten well-known peer-reviewed CEM journals published in the period of 1990–2012. Topic coverage, application requirements, and statistical techniques in the 88 Delphi papers are reviewed. The mix use of the Delphi method with three advanced modelling methods, such as Fuzzy sets, Analytical Hierarchy Process, and Analytical Network Process is also examined. These review results provide practical references for researchers having interests in applying Delphi method in CEM research. First published online: 21 Jan 2016
Slender steel frame structures are characterised by a number of imperfections which may reduce their load carrying capacity drastically. This article studies the effects of these imperfections on the load carrying capacity of a single storey steel plane frame using global sensitivity analysis and geometrically nonlinear (second-order) elastic finite element analysis. Imperfections are considered as random variables. Statistical load carrying capacities needed for the evaluation of sensitivity analysis are processed using classical statistical methods upon the emulation of Latin Hypercube Sampling simulation methods. The main interaction effects of random imperfections on the load carrying capacity are identified using global sensitivity analysis. It is illustrated that the effects of imperfections on the load carrying capacity varies dramatically depending on the height of the columns and the boundary conditions of the end conditions of the columns.
The higher life quality standards, the changes of habits and new well‐being requirements have led to an increase in the demand for housing. Decision‐making problems in construction management often involve a complex decision‐making process in which multiple requirements and conditions have to be taken into consideration simultaneously. However, not every attribute used in multidimensional scaling is equally and precisely weighted in the real world. Thus quantitative and qualitative assessments are often required to deal with uncertainty, subjective and imprecise data. The accuracy of performance measures in common multi‐attribute methods is usually assumed to be accurate. Grey theory is a new technique for performing prediction, relational analysis and decision‐making in many areas. This paper considers the application of grey relations methodology for defining the utility of an alternative and is proposed as a method of multiple criteria COmplex PRoportional Assessment of alternatives with Grey relations (COPRAS‐G). In this model parameters of the alternatives are determined by the grey relational grade and are expressed in intervals. A case study of assessing external walls of four alternatives was used to demonstrate the applicability and the effectiveness of the proposed approach. The results show that this method can be implemented as an effective decision aid in multi‐attribute selection. Santrauka Straipsnio tikslas – pasiūlyti alternatyvią daugelio rodiklių vertinimo metodiką. Šios metodikos išskirtinumas – rodiklių reikšmės, aprašomos intervalais. Tai labiau atitinka realias aplinkos sąlygas ir galimas reikšmes. Modelis su intervaluose pateiktomis efektyvumo rodiklių reikšmėmis pritaikytas E. K. Zavadsko ir A. Kaklausko sukurtam metodui COPRAS (Complex Proportional Evaluation). Taip gautas naujas metodas COPRAS-G. Šis metodas pritaikytas daugiabučių namų išorinių sienų efektyvumo vertinimo uždaviniui spręsti. Sudaryta efektyvumo rodiklių sistema, nustatyta efektyvumo rodiklių reikšmė, rodiklių rangas. Pagal sudarytą modelį pritaikę COPRAS-G metodą, galime spręsti daugelį statybos, vadybos alternatyvų vertinimo uždavinių. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: sienos, alternatyvos, daugiatikslis parinkimas, vertinimas, COPRAS, COPRAS-G, pilkieji skaičiai.
The paper deals with the analysis of reliability of a hot-rolled steel IPE-beam designed according to Eurocodes. A beam at its ultimate limit state is considered. The load acting on the beam consists of permanent and long-term single variation actions. The beam is loaded with end bending moments about the major principal axis. The beam is susceptible to lateral torsional buckling between the end supports. Reliability of the beam is assessed using probabilistic analysis based on the Monte Carlo method. Failure probability is a function of the random variability of the loadcarrying capacity and the random variability of load effects. The variability of the load-carrying capacity is influenced by the variability of initial imperfections. Imperfections are considered according to experimental research. Numerical studies showed that the failure probability is significantly misaligned. High values of failure probability were obtained for slender beams, for beams loaded only by permanent load action, and for beams loaded only by long-term single variation load. In further studies the values of partial safety factors of load and resistance were calibrated so that the failure probability had a target value of 7.2E–5. Relatively high values of partial safety factors were obtained especially for beams with high slenderness.
Building Information Modelling (BIM) processes have continued to gain relevance in the Architectural, Engineering, and Construction (AEC) industry with more resources directed toward it. This study conducts a bibliometric analysis of 445 BIM articles to investigate and understand the pattern of BIM research which include defining BIM research categories, evaluating the project sectors that are influenced by BIM, and tracking the funding structure of BIM research. A network map that displays a visualization of the structure of BIM literature by research origin, funding structure and geographical scope was designed. None of the previous reviews of literature analyzed the BIM articles’ corpus to such level and depth. The findings revealed research categories such as construction and project management and BIM learning, adoption & practice as the core research areas in BIM and highlighted trending research themes in BIM research. Authors based in Asia and Europe received more research grants than their counterparts in other regions; likewise, two-third of the articles was authored by academics in the United States, Korea, and the United Kingdom. The study provides its readers with relevant research areas that require considerations, and the discussion of selected research areas provides an extensive understanding of salient BIM fields.
International construction joint ventures (ICJVs) have been widely used in large-scale infrastructure projects all over the world. This study aims to investigate the factors affecting adoption of ICJVs for underground rail construction projects, to identify the critical risks faced by parties that perform the projects under ICJVs, and to examine the obstacles to appropriate risk allocation among the parties under ICJVs. To achieve these objectives, an in-depth literature review was carried out and a questionnaire survey was conducted with 33 contractor firms as well. The survey results reported “sharing of project risks” as the top attractive factor of ICJVs and “differences in culture and working style” as the top negative factor. In addition, both foreign and local contractors considered “partners disagree over some conditions in contract” the most critical risk to the parties involving projects under ICJVs. While risk allocation was perceived to be very important for ICJVs, “unclear division of responsibilities and risks” and “differences in culture and working styles” could be the most significant obstacles against effective risk allocation among the parties. The findings from this study will help improve the implementation of ICJVs and provide valuable information for organizations who intend to participate in ICJVs in Singapore.
The built environment is not constructed in empty space. It refers to human ‐ made spaces they live and work in and which are affected by various micro, meso and macro level factors. For this purpose, renovation decisions must be considered avoiding a narrow approach to the single projects of building renovation. Renovation of the built and human environment must be considered instead and the holistic approach used. From this perspective, decision‐making problems of renovation often involve a complex decision making process in which multiple requirements and conditions have to be taken into consideration simultaneously. This paper describes the concept of the integrated analysis of built and human environment renovation as a whole as well as presents the multiple criteria assessment of alternatives of the Bulgarian cultural heritage renovation projects. The widely known multiple criteria assessment methods SAW, TOPSIS and COPRAS and the newly developed method ARAS were used for this purpose. As a result the best project for granting was selected. Santrauka Gyvenamoji aplinka sukurta žmoniu ir skirta ju poreikiams tenkinti, ja veikia daugybe makro‐, mezo‐ ir mikroaplinkos veiksniu. Kadangi gyvenamoji aplinka yra kompleksiška, jos atnaujinimo sprendimai turi būti priimami vengiant pernelyg siauro požiūrio, nagrinejant tik pavieniu pastatu atnaujinimo projektus. Atnaujinimo sprendimai turetu būti priimami ir projektai igyvendinami taikant holistini požiūri. Šiuo požiūriu atnaujinimo sprendimai yra sudetingi, juos priimant būtina atsižvelgti i daugeli salygu ir reikalavimu. Šiame straipsnyje gyvenamosios aplinkos atnaujinimas nagrinejamas kaip visuma, pateikiamas autoriu sukurtas integruotas gyvenamosios aplinkos atnaujinimo analizes modelis, atliekama Bulgarijos kultūros paveldo atnaujinimo projektu daugiakriterine analize taikant gerai žinomus daugiakriterinio vertinimo metodus SAW, TOPSIS ir COPRAS bei naujai sukurta metoda ARAS. Atlikus tyrima išrenkamas geriausias atnaujinimo projektas, kuriam gali būti suteiktas finansavimas. First Published Online: 24 Jun 2011 Reikšminiai žodžiai: gyvenamosios aplinkos atnaujinimas, modelis, hierarchine kriterijų sistema, daugiakriterinis vertinimas, geriausia alternatyva
One of the most difficult problems in construction is taking objective decisions. A decision-making process is very complicated and time consuming (due to the complex nature of construction projects). Many experts with extensive knowledge of construction industry take subjective decisions related to verbal methods of decision-making. Difficulties are related mostly to the creation of a set of relevant criteria, providing answers to the decision-maker’s questions. A set of proper criteria and mathematical tools (such as computer calculation algorithms with multi-criteria analysis) could significantly improve objective decision-making. The paper presents ESORD – an informatics tool allowing to establish a hierarchy (ranking) of different types of solutions on the basis of mathematical calculation. The authors present a comparison of different methods used for multi-criteria decision-making.
Existing risks in deep foundation excavation projects is a major issue in developing cities. With the rapid in-crease in the number of various deep foundation and excavation projects in big cities of Iran, many accidents related to deep excavation have been reported every year. These accidents affected delay and increased cost of project implemen-tation. Therefore identification and assessment of risks of these accidents is essential. The aim of the research was to develop a framework to overcome limitations of previous approaches to assess of risks in excavation projects. According to the complexity of a problem and the inherent uncertainty, the framework adopted SWARA (Step-wise Weight As-sessment Ratio Analysis) and COPRAS (COmplex PRoportional ASsessment) methods through introducing new criteria for risk assessment. Data was collected through interview, a literature review and a questionnaire survey distributed to excavation project experts. A case study of deep foundation excavation in Shiraz was presented. The results have shown that the risks involving construction safety, unfavourable geological conditions, shortage of managerial experience, in-complete emergency plan and subsidence of ground are the most significant risks excavation projects in Shiraz. The proposed framework and the obtained results can help stakeholders of excavation projects in developing countries better to manage project risks.
This paper presents an innovative approach of integrating Building Information Modeling (BIM) and expert systems to address deficiencies in traditional safety risk identification process in tunnel construction. A BIM-based Risk Identification Expert System (B-RIES) composed of three main built-in subsystems: BIM extraction, knowledge base management, and risk identification subsystems, is proposed. The engineering parameter information related to risk factors is first extracted from BIM of a specific project where the Industry Foundation Classes (IFC) standard plays a bridge role between the BIM data and tunnel construction safety risks. An integrated knowledge base, consisting of fact base, rule base and case base, is then established to systematize the fragmented explicit and tacit knowledge. Finally, a hybrid inference approach, with case-based reasoning and rule-based reasoning combined, is developed to improve the flexibility and comprehensiveness of the system reasoning capacity. B-RIES is used to overcome low-efficiency in traditional information extraction, reduce the dependence on domain experts, and facilitate knowledge sharing and communication among dispersed clients and domain experts. The identification of a safety hazard regarding the water gushing in one metro station of China is presented in a case study. The results demonstrate the feasibility of B-RIES and its application effectiveness.
A multi-criteria decision-making system based on the MIVES method is presented as a model for assessing the global sustainability index scores of existing wind-turbine support systems. This model is specifically designed to discriminate between tower systems in order to minimize the subjectivity of the decision and, thus, facilitate the task of deciding which system is best for a given set of boundary conditions (e.g., height, turbine power, soil conditions) and economic, social and environmental requirements. The model’s versatility is proven by assessing the sustainability index of an innovative new precast concrete tower alternative also described in this paper. As a result of this analysis, some points of improvement in the new system have been detected. First published online: 23 Jun 2016
One of the major concerns in the construction industry is the sustainability of building projects. There are various trade-offs between functionality and design, which often lead to an issue of whether sustainably designed buildings would meet stakeholder requirements. This paper provides a novel integrated structure for assessing green buildings realistically based on stakeholders’ fuzzy preferences. In particular, the paper uses the analytic network approach (ANP) to evaluate the correlation matrices in a quality function deployment (QFD) framework. A case study on green building index assessment in Malaysia illustrates the proposed integrated method. Sensitivity analysis validated the customer-stakeholder agreement towards the design of the green building. Cluster analysis was also used to group design specifications prior to the analysis.
The paper presents a novel approach to solve problem of stairs shape assessment for two-story individual dwelling houses. Selection among available shapes and construction of stairs is a multi-criteria decision-making problem in nature. It depends on a set of different conflicting criteria, that have different optimisation direction, different measurement units. There is determined the set of the main criteria to assess the alternatives is as follows: Stairwell Area, The Total Area of Climbing, “Climbing Lane” Area, The Cost of Stairs, and Ergonomics. A novel original hybrid MCDM (multi-criteria decision-making) model, which based on ten different multi-criteria decision-making methods: Game Theory, AHP, and SAW, Multiplicative Exponential Weighting, TOPSIS, and EDAS, ARAS, Full Multiplicative form, Laplace Rule, and Bayes Rule, is presented.
Urban greenery is a natural solution to cool cities and provide comfort, clean air and significant social, health and economic benefits. This paper aims to present the latest progress on the field of greenery urban mitigation techniques including aspects related to the theoretical and experimental assessment of the greenery cooling potential, the impact on urban vegetation on energy, health and comfort and the acquired knowledge on the best integration of the various types of greenery in the urban frame. Also to present the recent knowledge on the impact of climate change on the cooling performance of urban vegetation and investigate and analyse possible technological solutions to face the impact of high ambient temperatures.
A new testing method and estimation of the fracture toughness in Mode III (antiplane shear) of concretes containing: 0, 20 and 30% volume content of the class F fly ash (FA) was proposed. Fracture toughness tests were performed on axial torsional machine MTS 809 Axial/Torsional Test System using special device. The Device for the fracture toughness test at the Mode III fracture consisted of the cylindrical specimen with the formed initial crack, steel plates, and screws with washers securing the specimen in the press holders. The specimens applied for experiments were cylinders with dimensions of 150/300 mm, having an initial circumferential notch made in the half-height of cylinders. The specimens were subjected to pure torsion. The studies examined effect of FA additive on the parameter KIIIc. 20% FA additive causes a small increase of the KIIIc in comparison to the concrete without the FA, while 30% FA additive causes a significant decrease in fracture toughness. The fracture surfaces of the specimens analysed macroscopically were planar. Scanning microscopic observations (SEM) indicate that in the fracture surfaces multilevel cracks occur in the shape of semicircles.
This paper proposes the Analytic Hierarchy Process (AHP) as a tool to rank different critical success factors (CSFs) for construction projects in Lithuania. Considering the current lack of understanding of CSFs within the local context, this study is one of the first attempts to gain an understanding of the CSFs in the local industry. Our study revealed that, for construction projects in Lithuania, clear and realistic project goals, project planning, the project manager's competence, relevant past experience of the project management/team, the competence of the project management/team, clear and precise goals/objectives of the client, the project's value, the project's complexity and uniqueness, the project manager's experience, and the client's ability to make timely decisions are the top-ranking CSFs. In view of these findings, the study highlighted the key areas for successful implementation of construction projects in Lithuania.
Built environment data is of varying nature embedding various forms of sensitivities with potential legal, contractual, intellectual property, and security implications. The paper presents a governance approach for managing multi-actor, multi-discipline, and total lifecycle data, informed by a wide industry consultation conducted in the UK between March and September 2011. The study identifies a number of barriers in engaging with Building Information Modelling (BIM) efforts with a view of facilitating collaboration around a common and integrated project specification. A governance model is proposed that addresses the identified adoption blockers underpinned by a "mixed approach", that factors in various modes of information delivery, ranging from paper-based documents to object-based information conveyed by IFC (Industry Foundation Classes). A demonstrator system is developed and used to validate our BIM governance concepts. Our governance model is discussed in the context of the recent UK government BIM industry consultation document supported by a research and development (R&D) roadmap taking into account current industry structure and its various levels of stakeholders' maturity, capability and readiness.