Enhancing accuracy in cost estimation: structured cost data integration and model validation

Cost estimation for tendering is one of the leading causes of legal disputes in the architecture, engineering, construction, and facilities management (AEC/FM) industry. To date, there are no standardized procedures for verifying cost estimation accuracy. The association between cost data and geometric model objects is currently done manually, leading to time losses and inaccuracies in cost estimates. This study defines a new architecture for cost items within the Industry Foundation Classes (IFC) data model to ensure structured cost data, which is currently expressed in unstructured natural language. It encompasses the definition of a cost domain in IFC, potential relationships it may have with an IFC geometric information model, and the validation of these relationships through semi-automated verification procedures of structured data (geometric-cost). A specific case study, focused on a structural IFC model, is examined to assess current and future applications. Additionally, rules for BIM information requirements will be defined through the Information Delivery Specification (IDS) to ensure clear understanding for both humans and computers. This will specify which data must be included in the geometric model to ensure validation and verification of the uniqueness of associated cost data. The results demonstrate the feasibility of defining structured cost elements in IFC and verifying their association with geometric data to ensure coherence and uniqueness in cost estimation.