Odysseus G. Manoliadis

Sustainable construction and drivers of change in Greece: a Delphi study

During the last decade, sustainable development issues have been gradually adopted in Greeces construction industry, changing the traditional methods and technology. The aim of this investigation is to identify potential drivers of change, to position them properly in the wider context of sustainable construction and to outline the progress to be expected in the coming decade. The methodological framework used is a Delphi technique based on a questionnaire of 20 experts (consultant engineers, construction managers and contractors). The results show that the most important influences on sustainable construction in Greece are energy conservation measures, resource conservation strategies and waste reduction. In terms of the initiatives expected in the coming decade, energy conservation measures, waste reduction measures, as well as product innovation and certification are expected to rank high. In conclusion, the results are consistent with those of previous researchers showing significant trends towards land use, energy, and resource conservation.

Sustainability Components Affecting Decisions for Green Building Projects

Construction process is the broad mechanism for the realization of human settlements and the creation of infrastructure that supports development. This includes the extraction and beneficiation of raw materials, the manufacturing of construction materials and components, the construction project cycle from feasibility to deconstruction, and the management and operation of the built environment In Greece, the complex problems shared by cities are evidence of the impacts of urban sprawl. This research aims to investigate the sustainability components affecting decisions for green building projects. The research method is based on a questionnaire survey of thirty two participants who asked to assess nine sustainability components namely: Life cycle assessment, energy efficiency and renewable energy, water efficiency, environmentally preferable building materials and specifications, waste reduction, toxics reduction, indoor air quality, smart growth and sustainable development and environmentally innovative projects, which affect the decisions for green building projects. The respondent results indicate how participants prioritized the sustainability components ensuring a better quality of life inside buildings based on the principals of “green” buildings economy. Energy efficiency and renewable energy is considered of high priority followed by the reduction of toxic materials, indoor pollution and water saving.

Assessment of the economic benefits from sustainable construction in Greece

The growing awareness of involving the criterion of sustainability in building design imposes questions of economic assessment of the proposed solutions. The aim of this research is to assess the economic benefits of sustainable construction in Greece. A questionnaire posed to 19 experts (consultant engineers, construction managers and contractors) based on the Delphi technique was carried out in order to gather experience on the economic benefits of sustainable construction. In particular, it is more economical at the operation phase of life cycle assessment and sufficiently important to be adopted at the design phase. Among the economic benefits of sustainable construction, reduce energy usage (REU) ranks first, followed by protection of the natural and social environment (NSE) and providing a healthy comfortable living environment (HLE). The results of the study show that the majority of experts believe that sustainable construction is overall more economical than standard practice.

A compromise programming model for site selection of borrow pits

Road fill construction requires soil for filling low areas; this soil is obtained from temporary mineral workings known as ‘borrow pits’ (BP). Between a number of possible BPs, the appropriate site should be selected based upon conflicting econo‐technical and environmental criteria aiming at achieving optimal BP performance while minimizing the adverse impacts to human and natural resources. For solving this problem a model for BP selection has been developed by this research using compromise programming (CP). The model incorporates a hierarchical structure integrating criteria and sub‐criteria whose relative importance is set by the decision makers. Possible alternative BP sites are subsequently assessed on all these sub‐criteria. Based upon this analysis, the model determines the distance of each of the possible alternatives from the utopia (ideal) point; the option with the minimum distance is considered the best compromise. The relevant concepts are exemplified through the presentation of a case study concerning the BP site selection for an Egnatia Motorway section in northwest Greece. The main conclusion that can be drawn from this work is that the CP approach is appropriate and valid for BP selection and, furthermore, it may also be used for other multiple objective construction‐related site selection problems.

A practical approach to resource - constrained project scheduling

In this paper a solution approach is discussed for managing projects with resource constraints. For this purpose a heuristic method is developed based on traditional CPM scheduling calculations and leveling algorithms. The method can be applied using normal scheduling software such as P3 and MS project, and as such, it is of value to practitioners. An illustrative example is also presented herein to exemplify the concepts. The problem solved has importance and direct application to the management of a wide variety of project-structured efforts with prevailing resource constraints.

compromise programming model in site selection for construction temporary facilities

One of the important project resources that have been overlooked during the planning phases of most construction projects is site selection of temporary facilities. In some projects, site selection can be as crucial as any other construction resource. Researchers have attempted to put together models that perform or assist planners in site selection. The aim of this paper is to present a framework for utilizing compromise programming (CP) for site selection of Construction Temporary Facilities (CTF) Compromise programming is used as a comprehensive tool that enables comparison between CTF alternatives. The CTF to be located concerns a site selection study conducted to evaluate locations for an onsite concrete batch plant to support the construction of the proposed facilities at the Savannah River Site. A comparison between the proposed model and Analytical Hierarchy Programming (AHP) models recently appeared in the literature is presented. As a construction management tool the proposed methodology describes better the trade-off between engineering performance (engineering, geoscience) and environmental performance (ecology, human health). However, the decision-making is project specific and relies on technical characteristics effectively limited the CTF site selection process criteria and the relative importance (weights) of the different factors involved.

A decision analysis framework for vendor selection in construction projects in greece

The aim of the present paper is to model the vendor selection process in construction projects in Greece. The applied approach involves a multicriteria rating technique used for calculating a normalized economic bid for the alternatives (i.e. vendors) by determining a proposed multiplier coefficient. This technique uses two stage compromise programming procurement criteria and weights according to the relevant legislative framework for government procurement to provide a multicriteria value score for each vendor. The application of the approach is demonstrated by an illustrative example concerning the procurement of earthmoving equipment (i.e. bulldozer). The primary advantage of this approach is that it incorporates a degree of subjectivity into the evaluation process in compliance with the existing legislative framework.

Sustainability Criteria for Awarding Construction Contracts in Greece

Nowadays multiple criteria have been added to the decision making procedure as a result of the harmonization of Greece’s public procurement to EU guidelines (i.e. 72/62/EC, 93/36/EC and 80/67/EC). The main objective of the research is to propose an evaluation methodology as a group decision framework for this problem. In doing so a systematic procedure is introduced based on Delphi technique aiming to evaluate the capability of grouped vendor suppliers to deliver the project as per the owners requirements. The order of the tenders is derived by comparison of the tenders’ efficiency. A case study is used as an example from a procurement case in Greece using criteria indices namely the Risk management, Quality of work, Price certainty, Time availability and predictability, Technical capacity of tenderers, Regularity of Environment, Energy intensity of building operation, Economic and Financial capacity of tenderers, Familiarity of tenderers of a building project. The results strengthen the opinion that the Delphi method paired with discriminant analysis is a powerful and appropriate technique for deriving objective solutions in categorization of procurement cases and is a rather subjective area such as the procurement system for vendor selection. This research outlines a process by which the traditional tenders’ selection using discriminant analysis method can be improved via the utilization of a Fuzzy Delphi Method (FDM), a cross-mutation of the traditional Delphi Method (DM) and fuzzy logic (FL).