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The paper presents a hybrid-enhanced algorithm based on CSS for discrete problems whit the focus on traveling salesman problem. The CSS algorithm based on some principles from physics and mechanics, utilize the governing Coulomb law from electrostatics and Newtonian laws of mechanics. However, the CSS is more suitable for continuous problems compared with discrete problems. In this paper, we have tried to resolve this defect of CSS algorithm with the help of local search methods and nearest neighbor for discrete problems whit the focus on traveling salesman problem (TSP). To prove the efficiency of the proposed algorithm, results compared with the results of benchmark problems. Then, the proposed algorithm is used to solve the TSP, using as a method for solving the single row facility layout problem (SRFLP). To prove the efficiency, the results are compared with the results of benchmark problems reported in the recent literatures.

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In the water industry tunnels can be used to transfer water from a basin to other areas over varying distances. The construction of such tunnels is inherently risky and can result in unpredicted events and incidents. It is therefore necessary that thorough risk assessments are carried out as a priority of the owner, contractor and consultant organization. This is so that, through a systematic and logical plan, they can risk posed by these unforeseen events and incidents. In this paper, the risks and their main causes which are often encountered in such projects are identified and assessed. A fault tree method is applied in order to identify the main causes of events and incidents. By its nature a Risk assessment cannot be defined by absolute values and so fuzzy data must be used in order to calculate the probability of incidence and the severity of the risk. This is done on the four main criteria of time, cost, quality and safety. In order to estimate the significance of each criterion and to calculate the significance of the total influence of risk Analytic Hierarchy Process (AHP) is applied. In this paper the case study of Dasht-e Zahab water conveyance tunnel has been selected for discussion as it was subjected to severe and multiple hazards. The results obtained using the method were validated by conducting different interviews with the field experts. It was concluded that by applying the proposed methodology on the case study the risks of the project can be evaluated in a more methodical and accurate way than could be done without using the method. This approach is therefore recommended for similar types of projects where there are complicated risks that must be thoroughly investigated and understood.

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This paper aims to develop a quantitative game model for preventing construction project managers from moral hazard problem from the standpoint of construction enterprises in China. The authors analyze the sources of construction managers’ moral hazard behaviors under China’s specific situation on the basis of the principal-agent theory, establish a game theoretic model to analyze the moral hazard problem between construction enterprises and construction project managers, and calculate the equilibrium solution through building up the payoff matrix. Our crucial contribution is a quantitative characterization of risk deposit system and performance appraisal system which help to resolve the moral hazard problem of construction project managers. The solution results show that the probability of moral hazard problem of construction project managers can be reduced after implementing risk deposit system and performance appraisal system. Thus the two systems we proposed can be taken by China’s construction enterprises as the effective measures to resolve moral hazard problem of construction project managers.

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Project Management knowledge has been used in many project oriented organizations in last two decades across the world. Despite, rate of project success did not change during these years. We believe there is a basic challenge in projects environment for managing them based on its inherent characteristics. In fact, project management knowledge use theories and concepts that are belong to process management world, as a different world. There is no enough attention to project characteristics as a fundamental differentiation for coping projects. Identification of construction projects nature in order to discern variables that create the project behaviors is main concern of the paper.Considering project characteristics in this research revealed construction project nature creates from combination two aspects. First, detecting environmental changes to develop a need and second prepare resources structure to respond the need. Important management challenge in this model is environmental continuous changes that alter the need and exchange resources structure. So, the paper considers how these aspects can be operationalized for developing a dynamic project management model. It gives some ideas about why project complexity might be considered to be increasing, and how construction projects move towards shorter timescales. The effectiveness of the model is verified by applying it for predicting some construction projects behavior. The results of the paper may capable future project managers to test any decision before its applying and lead to a new project management tool for construction projects management.

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Employer Organizations have increasingly interested in outsourcing their projects in the form of public-private partnership (PPP) due to various reasons such as compromising the resource limitations, entering new technologies to the organization and reducing risk. Choosing the private sector as one of the most basic steps in the formation of PPP is of great importance. The present study aims to introduce a hybrid model to evaluate and choose the private sector as one of the parties in PPP using a combination of SWOT-AHP analysis, as one of the most powerful tools in identifying the problem environment, and Fuzzy ELECTRE analysis to evaluate the existing candidates to participate in the partnership using the criteria resulted from SWOT analysis. In first step, criteria set by an organization, as a case, to choose appropriate private sector were identified using SWOT method during various meetings with qualified experts. Then, the best choice was selected using ELECTRE method. Finally, obtained results were compared with the PROMETHE method. The results showed the effectiveness of our proposed method to select private partnerships especially positive and negative inter-organizational and outer-organizational factors significantly influence the private sector selection.

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Workers who carry out manual rebar tying tasks are exposed to muscular-skeletal injuries associated with the use of manual tools and the movements associated with them (force, repetitiveness and awkward wrist postures). This paper presents a background on musculoskeletal injuries directly linked to manual and mechanical rebar tying method is conducted. The objective of this study is to compare the traditional manual rebar tying method to the innovative mechanical technique. The methodology carried out follows a qualitative and a quantitative analysis of both processes. Firstly, a qualitative analysis is performed by semi-structured interviews to workers. Secondly, a quantitative study is carried out in the region of Andalusia (Spain). This field study includes on-site measurements of lengths of time activities. According to the methodology developed by the International Labour Organization, the work timing is calculated and a comparison is given. Results state that the operators adapt without difficulty to the mechanical method and it could result in better performance, whilst reducing some of the risks deriving from the manual tying technique.

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The purpose of this study is to investigate the influence of cross-cultural communication (CCC) on stakeholder management process (SMP) in international construction projects from the Turkish stakeholders’ perspective. The research is based on a survey of Turkish stakeholders (contractors, consulting engineers, insurance brokers, and financial advisors) operating internationally. The useable survey comprised 141 individual responses from 205 distributed, giving a response rate of 68.78 percent. Structural equation modelling (SEM) is proposed as an effective tool to investigate the relations between various factors of cross-cultural communication and stakeholder management process and data regarding the Turkish stakeholders have been used to demonstrate its applicability. The results demonstrate that “Communication behaviours” and “Communication strategies” proved to be strongly significant and positively related to SMP, whereas “Communication barriers” have significantly negative effect on SMP. Research findings may encourage the principles and practices of CCC between the stakeholders to be adequately recognized and understood by the international contracting firms operating abroad. Although findings reflect the Turkish stakeholders’ perspectives, it is believed that the parameters identified in this study can further be used as a benchmark to conduct similar studies in other countries. Managers of international contracting firms can develop a Cross-cultural Communication Statement (OCQS) to assess, report, and develop cross-cultural communication between stakeholders of a multi-cultural project environment.

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The management philosophy, namely, Customer relationship management (CRM) has been widely accepted and successfully applied across a range of sectors. However, there has been very little research efforts in the field of CRM in the construction industry. This paper provides a review of the CRM philosophy and technology, and considers the implications benefits and challenges to construction organizations at a strategic business and operational level. Given the generally unstable economic and highly competitive marketplace, implementation of CRM throughout the lifecycle of assets may provide for more effective management of existing and prospective clients. The CRM approach would seem to be compatible with general trends in the construction industry towards more collaborative working and the paper provides that both the philosophy and technologies can be integrated with current initiatives such as building information modeling (BIM). Construction clients in the public and private sector are diverse in nature, complex in their buying processes and at varying levels of knowledge of the Industry. In addition to seeking value for money from their projects and assets, they have become more concerned about sustainability and environmental impact. It has been recognized that management of a broader range of business and project level stakeholders is necessary.

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The paper presents the characterisation of an Algerian natural pozzolan (NP) intended to for use in cement-based materials. The experimental programme was based on different tests on paste and mortar. The pozzolanic activity was assessed by the means of lime consumption over time of mixtures of lime-pozzolan (75% NP and 25% Ca(OH)₂, water-binder ratio of 0.45). The degree of reactivity was assessed by observing the crystallographic changes (XRD) and lime consumption (TG) up to 1 year of hydration. The effect of NP on cement-based mixtures was based on the measurement of the water demand and setting time of pastes, and on the compressive strength of mortars, up to one year. The replacement rates of cement by pozzolan were 5, 10 and 15%. A superplasticizer was used (0, 1, 2 and 3% of the binder mass). A calculation of the carbon footprint was investigated in order to assess if the natural pozzolan could be considered as eco-efficient when used in replacement of the clinker. The results showed that NP had a medium pozzolanic reactivity and with a medium-low silica content. The use of NP usually led to a small increase in the water/binder ratio (up to 10%) to maintain constant workability. The setting time was also increased by around 20%. Nevertheless, strength tests showed that the pozzolan had sufficient activity to counteract the water demand, since long-term compressive strength of the binary system (cement + pozzolan) were higher than those of cement alone. The use of NP in replacement of clinker involves a reduction in CO₂ emissions for transport up to 1800 km, which is compatible with sustainable development. The results are most promising from both a performance-based and an environmental point of view

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Construction industry projects impose unsought constraints on employers to manage and define new projects including investment risk, performance variation and diversity of the project. Annually, a significant part of the governmental budget is being spent to execute water and wastewater projects in Iran. However, further projects are on demand to develop the country. The aim of this study is to develop courses of action to attract private partnership into the projects defined and executed in the water sector of the Iranian Ministry of Energy. To determine the criteria and implementing the proposed strategies, SWOT (Strength, Weakness, Opportunity, Threat) method was used as a powerful tool for understanding the context of the organization. To understand the importance of criteria, we weighted them then the extracted strategies from SWOT matrix (ANP method) was prioritized and divided into short- and long-term range in terms of performance and capabilities. According to the results, SO strategies have more weight than other strategies. Therefore, regarding the nature of strategies, the opportunities should be completely used through reinforcing the strengths and short- and long- term periods planning.

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Risk allocation is the definition and division of responsibility associated with a possible future loss or gain arising from an identified risk. Quantitative approaches to risk allocation have been developed to overcome the limitations of qualitative approaches, especially the issue of the amount of risk to be borne by each party. This paper presents a cooperative-bargaining game model for quantitative risk allocation that extends the previous existing system dynamics SD-based model. The behavior of contracting parties in the quantitative risk allocation process is modeled as the players’ behavior in a game. The proposed model accounts for both the client costs and the contractor costs to perform the quantitative risk allocation process. To evaluate the performance of the proposed model, it has been employed in a pipeline project. Quantitative risk allocation is performed for the inflation as one of the most important identified risks. It is shown that using the proposed cooperative-bargaining game model, both the client and contractor costs are decreased in comparison to the previous SD-based risk allocation approach.

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Various methods have been applied to construction crew productivity problem. This paper additionally introduces the use of two novel artificial intelligent methods which are Self Organizing Maps and Artificial Bee Colony. It first presents the results of the prediction performances of these two methods and then focuses on the visualisation ability of SOM through the presentation of two dimensional maps produced for the current problem. The prediction performances are compared by comparing MAPE, MAE and MSE values obtained during seven fold cross validation. Two dimensional maps produced by SOM based model are additionally presented in order to analyse the relationship between labour related factors of crew size, age and payment method with productivity rates of ceramic tiling crews.

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Resource allocation project scheduling problem (RCPSP) has been one of the challenging subjects amongst researchers in the last decades. Most of the researches in this scope have used deterministic variables, however in a real project activities are exposed to risks and uncertainties that cause to delay in project’s duration. There are some researchers that have considered the risks for scheduling, however, new metahuristics are available to solve this problem for finding better solution with less computational time. In this paper, two new metahuristic algorithms are applied for solving fuzzy resource allocation project scheduling problem (FRCPSP) known as charged system search (CSS) and colliding body optimization (CBO). The results show that both of these algorithms find reasonable solutions, however CBO finds the results in a less computational time having a better quality. A case study is conducted to evaluate the performance and applicability of the proposed algorithms.

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This study proposes an efficient method for allocating the blood centers to hospitals based on the concept of graph partitioning (p-median methodology) and meta- heuristic optimization algorithms. For this purpose a weighted graph is first constructed for the network denoted by G0. A coarsening process is then performed to match the edges in n stages. Following the coarsening phase, the enhanced colliding bodies (ECBO) algorithm is applied to decompose the graph into a number of sub domains by use of p-median methodology. In our problem p is the number of blood centers which hospitals are intended to allocate. The results indicate that the proposed algorithm performs quite satisfactory from computational time and optimum points of view.

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The construction temporary facilities layout planning (CTFLP) requires an identification of necessary construction temporary facilities (CTFs), an identification of candidate locations and a layout of CTFs at candidate locations. The CTFLP is particularly difficult and complex in large-scale construction projects as it affects the overall operation safety and effectiveness. This study proposes a decision making system to decide on an appropriate CTFLP in large-scale construction projects (e.g. dams and power plants) in a comprehensive way. The system is composed of the input, CTF identification, candidate location identification, layout optimization, evaluation and selection, as well as output stages. The fuzzy logic is employed to address the uncertain factors in real-world situations. In the input stage, the knowledge bases for identifying CTFs and candidate locations are determined. Then, CTFs and candidate locations are identified in the following two stages. In the mathematical optimization stage, a multiobjective mathematical optimization model with fuzzy parameters is established and fuzzy simulation-based Genetic Algorithm is proposed to obtain alternative CTFLPs. The intuitionistic fuzzy TOPSIS method is used to evaluate and select the most satisfactory CTFLP, which is output in the last stage. To demonstrate the effectiveness and efficacy of the proposed method, the CTFLP for the construction of a large-scale hydropower dam project is used as a practical application. The results show that the proposed system can assist the contractor to obtain an appropriate CTFLP in a more efficient and effective manner.

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A formwork is a structure used to contain poured concrete and to mold it to the required dimensions. Different formwork systems provide a wide range of concrete construction solutions that can be chosen to suit the needs of a particular structure. The selection of panels and the design of the formwork layout for concrete structures, especially if the panels are to be reused many times to form different work zones, is one of the most complex tasks in formwork construction. It influences the quality of work, construction time, site safety and cost. The formwork costs account for a significant part of the total costs for concrete works. The problem of the selection and layout of reusable panel forms is solved mainly based on the intuitive judgment of experienced engineers in collaboration with the form system supplier. This study proposes a mixed integer linear programming modeling approach to support the formwork planning process. The problem consists in determining the number and sizes of the panels according to the geometry of the concrete elements in order to minimize the rental cost of wall shuttering in a building divided into work zones that are to be completed in sequence, reusing the chosen panels. The model can be solved using typical software dedicated to mixed integer linear programs. A simple example is used to illustrate the efficiency of the proposed approach, where the formwork rental costs is 7.31% lower than the rental costs of panels and corners optimized without consideration of the reuse in consecutive zones.

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The study presents a model for the evaluation of construction projects from the point of view of the investor. The problem lies in choosing the best solution from the point of view of many criteria. The proposed model is based on a multi-criteria comparative analysis using fuzzy logic. The first part of the paper presents a selection of criteria describing the construction project along with their description. The set of attributes describing the analyzed object was determined on the basis of the synthesis of specific proposals for the parameters of construction projects. The set of criteria has been divided into two groups: technical, technological and organizational criteria and separately the economic criteria. Then, the number of variables describing the observations was checked using principal component analysis (PCA). Course of action was presented in the event of multiple criteria analysis using the fuzzy set theory. Both the weights and the evaluations of individual criteria were modelled using membership functions due to the fact that when describing a construction project, or the validity of the criteria of describing variables, they are approximate. An analysis of the correlation of selected project criteria was presented. The proposed decision support model of assessing a construction project makes possible to compare various variants based on 11 factors identified. The use of fuzzy logic has enabled more accurate description of the phenomenon analysed when the exact parameters of the project in the planning and preparation stage of the project are not known.

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There are challenges and opportunities of deploying policies for transport infrastructure improvement in developing countries. Transport infrastructural development remains a major tool for achieving the aspirations of the newly introduced economic principles of the Federal Government of Nigeria. This study investigates the impact of innovative strategic approaches for improved transport policy and how the strategies are well incorporated to solve the problems faced in the infrastructure sector in order to enhance improved economic growth. The research involves a questionnaire survey conducted to key stakeholders in Nigerian six states. The study was focused on the stakeholders selected from the public entities, private clients, consultants, and contractors operating within the Nigerian construction sector. Based on the empirical data, the specific ways in which innovative strategies for transport policies affect infrastructure development contributing to sustainable economic growth have been shown. The findings contribute to the fields of innovative strategies for transport policies in infrastructure development by linking various aspects of innovative strategies for transport policies and infrastructure development and their interrelationships to sustainable economic development from stakeholders’ perspective. The results show that variables of innovative strategies in transportation and transportation infrastructure improvement have different roles and significant positive impact on sustainable economic development.

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Construction industries are the most dangerous worksites with high risk of occupational accident and bodily injuries, which ranges from mild to very severe cases. The aim of this study was to explore the causal factors of accident severity rate (ASR), in 13 of the biggest Iranian construction industries. In this analytical cross-sectional study, the data of registered accidents from 2009 until 2013 were obtained from an official database. Data of HSE risk management systems and HSE training were also gathered from comprehensive accident investigation reports. Data analysis and regression modeling were done using SPSS statistical software (version 22). The mean and SD of ASR of studied construction worksites was 257.52±1098.95. The results show that the system associated with HSE and HSE risk management established only 41.8 and 18.4%, respectively. The results of multiple linear regression indicated that some individual and organizational factors (IOFs), HSE training factors (HTFs), and Risk Management System factors (RMSFs) were significantly associated with ASR (p<0.05). The study revealed the causal factors of ASR. Hence, these findings can be applied in the design and implementation of a comprehensive HSE risk management system to reduce ASR.

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The study has been developed a qualitative System Dynamics model to measure sustainability performance of construction project, considering contractors’ tendency to productivity. Construction contractors do not have a clear understanding of sustainability especially in developing countries. However, they welcome higher productivity as a determinant parameter in scheduling and financial success of construction project. Therefore, construction productivity improvement can be employed as an incentive to persuade contractors for implementing sustainability mechanisms in construction project. Sustainability performance has been examined in three aspects of economic, social and environmental by introducing different subsystems and feedback loops. These loops are based on the causal links among the factors affecting construction sustainability and productivity. The findings provide a proper basis for both practitioners and researchers through illustrating the cohesion between productivity and sustainability.