3D modeling for computer-integrated construction of RC structures

This paper presents a three-dimensional (3D) geometric modeling scheme, for reinforced concrete (RC) structures, that takes into account the reinforcement detail. The node structure of rectangle adjacency graph (RAG) has been augmented to provide a complete 3D representation scheme. Further, a face-based modeling scheme has been developed to facilitate storage and manipulation of 3D geometric and topological information pertaining to structural components such as slabs, beams, and columns. The data structures designed to incorporate reinforcement detail employ a region-based approach and allow: (1) curtailment or splicing for longitudinal reinforcement and (2) variable spacing for stirrup/tie reinforcement. The modeling scheme presented in this paper can be employed for the development of computer-aided design/computer-aided construction (CAD/CAC) systems for RC structures, with rectangular/square columns, designed using one-way and two-way slab theories. Edge-to-edge and edge-to-contact-vertex topological relationships among the reinforcing bars are maintained in order to support computer-aided: (1) design; (2) detailing; (3) construction process planning; and (4) prefabrication of rebar cages. The geometric data structures designed to support the modeling scheme are efficient in storage and traversal performance.