First Findings on the Mechanical Analysis of Cob Using a Discontinuity Layout Optimization (DLO) Approach

Most of the remaining earthen vernacular buildings in the British Islands and northern France are examples of cob structures and represent invaluable cultural heritage assets. Despite their importance, the development and application of numerical modelling techniques on the study of cob’s mechanical behavior remains relatively unexplored, if compared to the level of interest dedicated to other earthen typologies such as adobe or rammed earth. In this paper, an alternative simulation tool known as Discontinuity Layout Optimization (DLO) has been explored to try to simulate cob’s mechanical behavior. Simple and diagonal compression cob wallettes tests were modelled using the software LimitState GEO. Two different refinement levels were tested, namely, medium (500 nodes) and very fine (2000 nodes). Failure loads and failure modes are reported and compared against simulation results obtained using a Finite Element Method (FEM) software and experimental results. Good agreement was found between the failure modes obtained from DLO models and experimental results. It is concluded that, although FEM remains the most valuable simulation tool for the study of cob structures, DLO has lots of potential based on its computational speed and the easily interpretable results in terms of explicitly identified failure mechanisms.