Proceedings of the CIB W78 2012: 29 th International Conference –Beirut, Lebanon, 17-19 October OPTIMISED STRATEGY BY UTILISING BIM AND SET-BASED DESIGN : REINFORCED CONCRETE SLABS Mehdi Bavafa, Doctoral Candidate, m.bavafa@edu.salford.ac.uk Arto Kiviniemi, Professor, a.Kiviniemi@Salford.ac.uk School of Built Environment, University of Salford Laurence Weekes, Dr, l.weekes@salford.ac.uk School of Civil Engineering, University of Salford ABSTRACT Considering the significant amount of material wasted in the construction industry there should be a business case for companies to pay more attention to reducing waste, which would also have a major impact on the environmental issues of the projects. Although structural engineers and architects have different roles in the design process in selecting construction systems and materials, they provide building information together. Building Information Modeling (BIM) could provide an opportunity for all relevant stakeholders to share their knowledge and experiences in the early stages of design and a platform for structural engineers to utilize Set-based Design in considering different alternatives for the optimal design of systems. This research suggests a conceptual strategy for enhancing an decision support model in parallel with stakeholders’ participation to achieve the optimal final solution in terms of material waste, by narrowing down the structural alternatives. The example used in the paper is reinforced concrete slabs, but the same principles are applicable to all structures. This research will focus on describing the BIM features, which could help the structural engineers to rank their criteria and select optimized design solutions. Keywords: BIM, Set-based Design, structural engineering, waste reduction, concrete slab. 1. INTRODUCTION The construction industry is an activity producing a significant quantity of material waste; the building industry consumes approximately 40% of the world’s raw materials. (Koskela 1992) and in the UK from the 420 million tonnes of materials used annually 120 million tonnes, 28%, becomes waste (Network Waste UK 2012)Already in the construction phase the waste of materials can constitute 2-3% of the total construction costs, which is about the same as the typical profit margin in the industry (Network Waste UK 2012). Previous research has indicated that the main reasons for physical waste in the construction industry are inappropriate preparation, inaccurate processing of materials and incorrect decisions in the design stage (Ballard 2000). The main reason for errors and delays in most processes is inconsistent and ambiguous information. Therefore, the construction industry requires explicit storage to share and exchange the project information between all participants (van Nederveen et al. 2010). It is commonly known that design and construction projects are too often running over budget and schedule because of errors and changes during the construction. BIM is expected to address some of the fundamental reasons for these problems by ensuring "getting the right information in the right format at the right time in the right place" (Tolman 1999)"BIM is a set of interacting policies, processes and technologies generating a methodology to manage the essential building design and project data in digital format throughout the building's life-