|M.Sc Student||Barak Ronen|
|Subject||Specification and Development of an Object Schema for|
Building Information Modeling of Cast-in-Place
Reinforced Concrete Structures
|Department||Department of Civil and Environmental Engineering||Supervisor||Professor Rafael Sacks|
|Full Thesis text - in Hebrew|
Commercial parametric 3D modeling software for design, fabrication and construction of structural steel and precast concrete structures is available, but for cast-in-place (CIP) reinforced concrete (RC) structures it is still limited to schematic modeling. The reason is that existing systems cannot support the unique requirements for modeling CIP concrete structures. The principle difficulty is the incompatibility between object-oriented modeling software designed for discrete building components and the non-discrete, monolithic nature of reinforced concrete. The goal of this research was to identify the conceptual differences and to specify new data schema objects to support CIP building information modeling of CIP structures.
A consortium of researchers, design firms, contractors and a BIM software company was brought together for a series of meetings to elicit the user needs for 3D parametric modeling and detailing of CIP structures. The first step was to compile a process model to describe the scope, work and information flows. From this, a detailed list of user requirements was compiled. The user requirements were then analyzed in order to distill the functional requirements that software must support in order to facilitate the various engineering and construction management activities of all actors throughout the process. The main schema object groups identified and defined were: connecting volumes, parametric manipulation and special geometry, work and pour packages.
The main conclusion is that it will be feasible to model CIP structures in BIM tools once these constructs have been implemented. The proposed connecting volume object solves the problem of the monolithic nature of CIP concrete, supporting multiple functional representations of structures using discrete objects. A second important finding is that the lack of distinction between fabrication and erection (a distinction that is sharp in the case of steel or precast) means that production management information must be integrated with product information; despite their physical form, pour sections and pour breaks are essentially management objects, rather than design objects.
The findings are basic in nature in the sense that they propose an object model schema that is different in fundamental ways from the object schema of existing BIM software applications. Nevertheless, Tekla Software Corp. of Finland, who partly funded the research and provided the data, has adopted the results, and will develop and implement several of the objects proposed.