Semi-automatic and specification-compliant cost estimation for tendering of building projects based on IFC data of design model

Cost estimation for tendering of building projects (TBP cost estimation, hereafter) is one of the most critical tasks in the architecture, engineering, construction, and facilities management (AEC/FM) industry. However, it is currently both time-consuming and prone to error because of the working complexity and comprehending deviation caused by the traditional two-dimensional representation of design. The advent of Building Information Modeling (BIM) technology enables a potential solution to these problems through the support of open data exchange standards such as the Industry Foundation Classes (IFC) standard. This paper discusses the key issues for semi-automatic and specification-compliant TBP cost estimation based on the IFC data of the design model, taking TBP cost estimation for the architectural and structural engineering of the cast-in-place concrete structure projects as an example. A Chinese national mandatory specification for TBP cost estimation is introduced as a representative specification and is interpreted into a computer-processable format. An IFC-based construction product information model of TBP cost estimation is established. A general process map and the involved key algorithms for semi-automatic and specification-compliant TBP cost estimation based on the IFC data of the design model are formulated. The application of the process map and algorithms in developing a prototype BIM-based software application for TBP cost estimation and the results of applying the prototype in an actual building project in China are presented. This paper lays a sound foundation for developing BIM-based software applications for TBP cost estimation in China, and demonstrates a feasible approach to satisfying the similar requirements in different countries.