A BIM based approach for construction and assembly driven optimisation of building design

During the design phase of construction projects, professionals seldom consider implications of design choices in terms of the ease with which it can be constructed. This contributes to wastage when chosen design features and materials result in the use of inefficient construction production and assembly methods. In order to bridge this gap, this study provides an approach for incorporating production knowledge and data into Building Information Models (BIM) to support optimization of building designs in terms of the efficiencies associated with their onsite production. A building design assessment system is developed to aid selection of alternative building design elements and materials in a digital prototype before they are actually constructed. The assessment system relies on an index derived from production knowledge or data related to ease of assemble, speed of assemble and the waste associated with the assembly or construction of a building element or material. This paper presents the identification and prioritisation of criteria for the development of the index for optimal selection of building envelope systems. The criteria were reviewed by an expert panel (n=25) who provided weightings of criteria importance through a voting analytic hierarchy process (VAHP). A schema for implementation through the extension of BIM with external assessment index logic is also presented. The practicality of the system as an indicator of the efficiency with which a design can be built or constructed, provides a solution for leveraging production knowledge and data to improve design in terms of its buildability thereby reducing waste associated with inefficient construction and sometimes redesign or late substitution of materials.