Development of an Automated Rebar Modeling Tool for RC Structures

Abstract

In Japan, the labor shortage due to population decline is becoming severe, and a productivity improvement has become an urgent issue in construction sites. Particularly, in construction projects dealing with diverse structures, the complexity and individuality of design pose significant barriers to productivity improvement. To address this challenge, the utilization of Building Information Modeling (BIM) has been mandated under "i-Construction 2.0, and the goal is to achieve semi-automated design through parametric modeling. This study proposes a novel method for automatically generating rebar models reflecting design parameters specified by the designer, to contribute to achieving this goal. Considering that conventional automation tools were constrained by specific structural body shapes and could not always fully meet designers' needs, this proposed method investigates an approach capable of robustly addressing these constraints and needs. The proposed method assumes typical civil engineering structural body shapes and categorizes them into shape-dependent and shape-independent parts. Subsequently, modules were constructed for the shape-independent parts. As a result, by developing additional programs only for the shape-dependent parts, it becomes possible to efficiently achieve rebar modeling that accurately reflects design intent, not only for simple rectangular structures but also for diverse and complex structural bodies. As a demonstration, automatic rebar modeling was performed for rectangular, cylindrical, and inclined rectangular structural bodies using a modeling system constructed based on the proposed method. The results confirmed that each rebar was modeled with appropriate placement and shape in compliance with design standards, demonstrating the feasibility of semi-automatic rebar design through parametric modeling.