A Parametric Template Format for Solid Models of Reinforced Concrete Structures

摘要

The trend in the architecture/engineering/construction industry toward the use of threedimensional representations of structures in design, analysis and construction has led to the acceptance of the Computer Integrated Manufacturing (CIM) Steel Integration Standards (CIS/2) format for steel structures [Fowler], [Hamburg and Holland]. This allows all information defining the structural steel to be passed among the structural designer, detailer, fabricator, and erector, as well as the other members of the project team, through a digital data file that eliminates the need for reentering information thus minimizing the potential for errors in translation. The three-dimensional model also facilitates the task of checking for interferences and inconsistencies which will reduce these problems during construction. This technology will continue to gain acceptance and must be developed for all components of the constructed project. A format is proposed for describing the geometry of typical reinforced concrete structures as a function of user-defined parameters. The structure is constructed from solid Corner, Beam and Slab components aligned with a flexible grid. Corners are analogous to finite element nodes while Beams and Slabs would be one- and twodimensional elements, respectively, in conventional structural models. Once the number of grid spaces is defined in the X, Y and Z directions, the template designates which grid 搒quares?are filled with a Slab and which are open. Slabs may be floors or walls and may have holes. Beam components are aligned with grid lines and may represent beams, columns, or elements that connect adjacent Slabs. Corners are hexahedrons at the intersection of grid lines. The dimensions of the components are defined as functions of parameters listed in the template. A simple application of this approach would be a template to model a multiple story concrete frame structure. Advanced commercial structural analysis programs such as RAMSteel?and ETABS?allow parametric input to quickly generate this type of structural model. A template for this structure could be designed with minimal parameters if column spacing and floor spacing were constants and all structural members had the same dimensions. This basic template can then be enhanced to give the designer more flexibility throughout the structure by adding additional parameters. The result is a solid model which can be used as a basis for a finite element analysis and structural design but also for detailing rebar, checking interferences, designing formwork, planning construction, exporting to another 3D design environment for architectural and mechanical/electrical/plumbing design, and for generating two-dimensional drawings of the structure. In the future solid models will be part of the permanent record of the constructed project. Two applications of the template format are developed: a simple reinforced concrete frame and a more complex reinforced concrete pumping station. The graphical user interface allows the designer to change any dimensional parameter to immediately update the structure geometry in order to meet the project requirements. The final solid model is then converted to a finite element model and analyzed to determine shear, moment and axial force in beams, columns and slabs. Algorithms are being developed to use these results to design the reinforced concrete members. A sampling of the results of the analyses is presented.