A Parametric BIM Framework to Conceptual Structural Design for Assessing the Embodied Environmental Impact.

Decisions made in the early design stage have a significant effect on a building's performance and environmental impact. In practice, a conceptual design is performed by an architect, while a structural engineer begins to work in later phases when the architectural concept has already evolved. However, the geometry and form of a building directly determine the type of structure and applicable materials; therefore, the conceptual design phase gives rise to examining alternative solutions. This paper presents a method for generating alternative structural solutions in the conceptual design phase and examining their embodied environmental impact by integrating parametric design and building information modeling (BIM). Rhinoceros and Grasshopper were used to develop the parametric script, which includes the generation of geometrical variations, the automatic definition of initial cross sections for the load-bearing elements based on in-built structural design approximations, the datasets for embodied environmental impact of the used building materials, the generation of life cycle inventory (LCI), the automatic calculation of life cycle assessment (LCA) results based on the geometry, and the conversion of the parametric model into building information model. The method was demonstrated using a case study of 48 different alternative solutions for an unheated warehouse made of steel frames. Based on the results, the areas with the greatest energy impact were identified. The case study analysis also illustrated that the applied cross section may have a significant effect on the impact categories. The results draw attention to the complexity of LCA calculations even in the case of a simple structure containing a limited number of variables, where parametric design can serve as an effective tool for a comprehensive environmental impact assessment. [ABSTRACT FROM AUTHOR]