Analyses of Structural Robustness of Prefabricated Modular Buildings: A Case Study on Mid-Rise Building Configurations

The limited knowledge of the behaviour of modular buildings subjected to different loading scenarios and thereby lack of design guidelines hinder the growth of modular construction practices despite its widespread benefits. In order to understand the robustness of modular building systems, a case study was carried out using the numerical analysis method to evaluate the robustness of ten-storey braced frame modular buildings with different modular systems. Two types of modules with different span lengths were used in the assessments. Then, three different column removal scenarios involving (1) removal of a corner column, (2) an edge column, and (3) an interior column were employed to assess the robustness of modular building cases considered. The forces generated in the elements in close proximity to the removed column were verified to assess the robustness of each building case analysed. The results showed that the change in damping ratio from 1% to 5% has no significant influence on the robustness of the modular building cases considered, where the zero-damping leads to collapse. Corner column removal has not considerably affected the robustness of the braced modular building cases studied. The axial capacity ratio of columns is 0.8 in dynamic column removal in the building subjected to corner column removal, while in interior column removal capacity ratio reached up to 1.2, making it the most vulnerable failure scenario. Doubling the span of the modules (from 2.5 m to 5 m) has influenced the robustness of the buildings by increasing the axial forces of columns up to 30% in the interior column removal scenario. Thus, this study highlights that proper guidelines should be made available to assess the robustness of modular building systems to effectively design against progressive collapse.