Structural optimization and environmental response analysis of modular buildings based on BIM

Abstract

Despite the benefits of efficiency and fast construction associated with modular steel structures, the structural design of modular buildings is faced with unique challenges concerning the connection properties between modules during different loads. This paper proposes a comprehensive BIM-driven approach integrating multi-objective optimization of the structure and assessment of the multi-physics environmental response to the building, namely a six-story modular steel building in Changsha, China. The parametric design carried out by using Autodesk Revit software, incorporating the attributes of wind, earthquake, and temperature effects, was utilized for analysis purposes. When combined with the finite element analysis via automatic IFC exchange, the NSGA-II algorithm provides a Pareto front consisting of 22 non-dominated solutions between steel usage and lateral stiffness; the adopted balanced solution demonstrates a reduction in the steel mass by 8.2%, compared to the un-optimized one, as well as the improved drift behavior. The environmental impact analysis for the optimized solution under wind loads, seismic excitations, and thermal conditions indicates that although the connection region of modules complies with all international standards, there is an increased wind stress concentration by 20.7%, seismic dynamic magnification of 2.16 at the horizontal module junction, and condensation potential in winter due to the temperature lower than the dew point at the inner surface of the connection junction. These vulnerabilities at the level of the connections, which cannot be detected using standard optimization strategies based on global performance indicators, prove the need to combine optimization with a multiphysics environmental evaluation strategy using a BIM model. Supplementary connection, stiffness-transition, thermo-mechanical, and thermal-bridge checks were added to clarify the robustness and limitations of the reported results.