Alternative Load Path Analysis of Timber Post-And-Beam Modular Buildings

Abstract

Timber modular buildings are an emerging construction method, due to the environmental and construction speed benefits. However, the inherent discontinuity and limited deformation capacity, hinders their ability to effectively redistribute loads under accidental load cases and thus, their robustness. A method to quantify the robustness of a building is to assess its behavior under notional column removal scenarios. This study numerically investigates the behavior of a hypothetical five-storey timber post-and-beam modular building under accidental damage events represented by four different column removal scenarios. The findings indicate that the structure could develop sufficient alternative load paths to sustain the amplified accidental limit state design load in most cases, primarily through flexural mechanisms. However, due to the limited ductility of these mechanisms, modular connections were optimally redesigned to enhance axial elongation and capacity, enabling the development of catenary action. The most effective strategy for achieving a robust catenary response was the introduction of a fuse element, significantly improving the ductility of the connection and enhancing the overall structural robustness.