Enhancing the integration of sustainability assessment within dynamic BIM enabled design projects

In the last decade, building information modelling has created a revolution transforming the architecture, engineering, and construction (AEC) industry. New ways to utilise new technologies and processes in visualising, managing, exchanging, predicting and monitoring project information are in continuous development and investigation. At the same time, global and governmental pressures have been acting as motivators towards delivering sustainable and low carbon buildings, and industry stakeholders are therefore committed to delivering buildings with reduced carbon. One of the main sources responsible for carbon in buildings is embodied carbon, which relies on the choice of building materials. Life cycle assessment is a methodology developed to assess the sustainability of the materials, dealing with the embodied factors throughout the whole life cycle of the material. Although there are promising possibilities for incorporating building system life cycle assessment (LCA) of materials into building information modelling platforms, dynamic and early design assessment is still lacking. The aim of this thesis is to investigate the problems faced in incorporating sustainability evaluation aspects with a focus on life cycle assessment, and to propose and test a framework and tool to facilitate the design of low carbon buildings. It begins with an exploratory phase where synthesis and analysis of the literature took place, aligned with an exploratory case study. By examining previous studies through a systematic literature review, this study highlighted current limitations and benefits between BIM and sustainability practices. A theoretical contribution was made through clustering six areas for future investigation of successful integration, which are: representation; performance simulation; transaction and exchange; documentation; automation; and standardisation and guidance. The scope of the study was then narrowed down to develop and test a model and framework for life cycle analysis as one of the main sustainability aspects that needs to be dynamically integrated in BIM workflow. The study design incorporated abductive mixed methods research involving the following three stage process: investigation phase of problematic areas in incorporation and existing platforms; designing and implementing a framework and dynamic LCA approach; and then evaluating its usability to validate it. The selected approach illustrates the LCA workflow possibility within a BIM environment using Revit platform, a UK current EC material database, and visual programming language (Dynamo) to link BIM objects to a database and optimise Embodied carbon (EC) within the design process. Eliminating ad-hoc work, manual mapping, the need for expertise, and complexity of required input information were the main objectives of the proposed approach. It was also important to test the usability of the simplified LCA methodology in order to validate the efficiency of using the system iteratively from the early design stage and through design development. Therefore, validation of the framework and tool was carried out through conducting qualitative and quantitative usability testing. The usability testing included a showcase presentation, online workshop testing and evaluation via a questionnaire and semi-structured interviews. The main outcome was the development of a model and framework to enhance informed decision making, reduce error, support the design of low carbon buildings, and reduce time end effort. It also provided an expandable framework that can be used with other different paraments in future, providing flexible opportunities for expansion and customisation. A key theocratical contribution in the developed model is the proposed use of a correction factor to overcome the problem associated with low detail. The workshop feedback provided insights into utilisation of visual programming language (VPL) and suggested areas for potential improvement including: more visualisation and optimisation options, development of an advanced user interface, and finally the inclusion of more environmental indicators and expansion of the model system boundary. In conclusion, the findings of the research contribute to fill the gap identified by providing a dynamic and automated approach to calculate embodied carbon. The novel way proposed by adding correction factor; to increase accuracy of calculation of low detailed BIM model, is an area of development for material database developers. In addition, the results from the usability testing are considered a basis for future development to be addressed by researchers and practitioners to increase adoption of the new VPL integrated approach. They provide evidence of the need to enhance the calculation model, visualisation and optimisation options, and develop a more advanced user interface for the tool.