Quantifying the environmental impacts and simulating the energy consumption of building’s components at the conceptual design stage are very helpful for designers needing to make decisions related to the selection of the best design alternative that would lead to a more energy efficient building. Building Information Modeling (BIM) offers designers the ability to assess different design alternatives at the conceptual stage of the project so that energy and life cycle assessment (LCA) strategies and systems are attained. This paper proposes an automated model that links BIM, LCA, energy analysis, and lighting simulation tools with green building certification systems. The implementation is within developing plug-ins on BIM tool capable of measuring the environmental impacts (EI) and embodied energy of building components. Using this method, designers will be provided with a new way to visualize and to identify the potential gain or loss of energy for the building as a whole and for each of its associated components. Furthermore, designers will be able to detect and evaluate the sustainability of the proposed buildings based on Leadership in Energy and Environmental Design (LEED) rating system. An actual building project will be used to illustrate the workability of the proposed methodology.

Purpose: Analyzing different scenarios at the design stage of construction projects has always been a challenging task. One of the main parameters that helps owners in making better decisions in designing their buildings is to look after the cost perspective on different design scenarios. Thus, this study aims to propose a semi-automated BIM-based cost estimation approach that enables practitioners to estimate the cost of projects based on different design scenarios by an accurate and agile system.Design/methodology/approach: This study proposes an integrated framework, through which the cost estimation standard of Iran (FehrestBaha) is linked to the materials quantity take-offs (QTO) from BIM models. The performance of the system is based on connecting the classification standards of UniFormat and MasterFormat to the cost estimation standard of FehrestBaha. A BIM-based extension in the Revit environment is developed to automate the cost estimation process.Findings: To evaluate the efficiency of the proposed approach in cost estimation, it is implemented to estimate the cost of the architectural discipline in a real construction project. The results indicate that the proposed BIM-based approach estimated the cost of the architectural discipline with an acceptable level of accuracy.Practical implications: The proposed approach could be used by practitioners to have an agile and accurate BIM-based cost estimation of different scenarios during design process. The semi-automated system considerably reduces the time of cost estimation in comparison to the traditional manual approaches, particularly in complex structures. Owners are able to easily trace changes in project cost according to any changes in components and materials of the BIM model. Furthermore, the proposed approach provides a practical roadmap for BIM-based cost estimation based on cost estimation standards in different countries.Originality/value: Unlike the traditional manual cost estimation approaches, the proposed BIM-based approach is not highly dependent on the knowledge of experienced estimators, which therefore facilitates its implementation. Furthermore, automating both QTO process and the required calculations in this approach increases the accuracy of cost estimation while decreasing the probability of human errors or omission occurrence.

Existence of diverse sustainable materials with distinctive features causes more difficult decision makings for project teams especially when it is intended to use ideal materials from diverse types of sustainable products. Few research studies have been conducted so far on applying Building Information Modeling (BIM) to act as Decision Support System (DSS) using of math works functions and tools in combination with Multiple Criteria Decision-Making (MCDM) techniques. The main purpose of this study is to propose a methodology that integrates BIM with decision-making and problem-solving approaches including Fuzzy and TOPSIS in order to efficiently optimize the selection of sustainable building components at the conceptual design stage of building projects. To select the optimum building components, each item is assessed against three major attributes of decision criteria as Design, Economic and Quality factors, which are applied in Multiple Attribute Decision Support System (MADSS) methodology to indicate the various performance of buildings sustainability. This BIM-integrated process is linked to the engine of Matlab software to apply Fuzzy functions on the users’ priority in order to automatically suggest the ideal solutions. The design alternatives suggested by Matlab is validated by Life Cycle Cost (LCC) method to analyze the operational cost of an actual building project. Using this innovative method will make the decision-making procedure more convenient as well as proposing more realistic and reliable final and sustainable optimized choice.