Automated Clash Resolution of Steel Rebar in RC Beam- Column Joints Using BIM and GA

Design of steel rebar in reinforced concrete (RC) members is usually conducted individually based on loading conditions, support conditions, and geometric conditions of the considered RC members only. Member-member interactions are rarely considered at the design stage, leading to potential rebar clashes (hard clash) or congestion (soft clash) at beam-column joints on construction sites. Currently, rebar clashes and congestion are often identified and resolved at the construction stage manually by site engineers or workers, which is a tedious and time consuming process. The building information modeling (BIM) technology allows us to digitally represent the detailing of steel rebar and transfer the detailing information to structural analysis software. However, automated identification and resolution of steel rebar clashes and congestion in RC members are lacking. This paper presents an automated steel rebar design framework based on BIM and genetic algorithm (GA) that considers and avoids rebar clashes and congestion at RC beam-column joints. Each beam-column interaction in a given RC frame is first analyzed to find out the type of each beam-column joint, such as T Joint and + Joint. GA is used to generate a first stage population containing steel rebar number and location for each RC member. Each individual of the population is then checked at all beam-column joints to avoid hard clashes between inter-member steel rebar. Optimal rebar diameter combination (with minimum rebar area) for each clash-free individual of the population is then calculated using the second stage GA based steel rebar optimization engine. The optimization engine contains a built-in checking function to avoid congestion between steel rebar. An illustrative example will be shown to test the developed framework.