Hybrid EVAS-CBR system for the preliminary cost estimation of high-rise buildings

Cost estimates at any stage need to be sufficiently accurate for cost experts to be able to control cost effectively. However, preliminary cost estimating is still considerably inaccurate (i.e. , ±50% error rate), because limited information is available on the numerous factors affecting project costs: these are either unknown or not appropriately taken into consideration. In spite of the country's experience with Korean High-Rise Buildings (HRBs) construction, cost estimating at the preliminary design phase is still considerably inaccurate. The main aim of this study is to overcome the limitations of existing cost estimation models for Korean HRBs and improve their prediction accuracy (i.e. , to under ± I 0% error rate) of cost estimation at the preliminary design phase through the use of a new hybrid approach, Excel Visual Basic Application System (EVAS)-Case Based Reasoning (CBR). CBR is a relatively new artificial intelligence approach that overcomes most drawbacks of present cost estimation methods by reusing the specific knowledge encapsulated in previously experienced problems when solving similar ones.