Research On BIM-based Computer Aided Formwork Design System

Formwork and support project is an important part of reinforced concrete construction. Formwork and support project accounts for a large proportion of the work amount and costs of construction. Formwork and support design consumes a lot of time and labor. In order to improve efficiency, nowadays the formwork and support service companies are using computer aided design systems. However, there are still some problems in the existing formwork and support design systems. When using existing design systems, the designer needs to re-input the structure model, which reduces the efficiency of the design; in these systems, the structural elements do not contain information about material, cost and other useful information. As a result, the information in the existing system cannot be passed to the latter stage of the project cost management or safety analysis systems. Building Information Model (BIM) technology provides an effective way to solve these problems.The research builds the formwork and support information model based on the Industry Foundation Classes (IFC). Because there is no definition related to formwork and support projects in IFC, the IFC is extended in this research to meet the demand of formwork and support projects. The extended IFC includes the formwork entity, the support entity and the entities which build the relationship among them. This research can extract the structural elements from the building information model and merge the formwork and support information model with the building information model through the partial-BIM extraction technique. The research presents a BIM based Computer Aided Formwork Design System (CAFDS) which is implemented according to the analysis of the workflow of the formwork and support design.By using the partial-BIM information extraction technology, The CAFDS solves the problem that the building elements need to be re-input. Based on BIM and CAD technology, the system can automatically design formwork and support projects. The formwork and support objects in the system implement intelligent design rules with regard to the interaction among various objects. Meanwhile, the system can store all the information of the formwork using AutoCAD custom entities and build the formwork and support information model based on IFC. The system can analyze the safety of the formwork and support project. The CAFDS makes the formwork and support design more accurate and more efficient, and shortens the work cycle of formwork and support design.