Finite element modelling of the progressive collapse of post-and-beam mass timber building substructures under edge and corner column removal scenarios

Abstract

The structural behaviour of mass timber buildings under a load bearing element removal scenario is complex. To well understand this phenomenon and ultimately develop scientifically based design guidelines against progressive collapse for this type of buildings, there is a need to develop a Finite Element model which accurately captures the non-linear response, load redistribution mechanisms (alternative load paths) and failure modes of such buildings. As such, this paper presents for the first time how mass timber post-and-beam systems can be accurately modelled using Finite Element under edge and corner column removal scenarios. The model was validated against published 2D and 3D experimental tests performed on scaled-down substructures. The non-linear structural responses of the main structural connections were experimentally quantified and inputted into the model using the component method. Results show that the model accurately replicated load redistribution mechanisms, ultimate loads, failure modes, and strain developments. The use of the model was then illustrated by running parametric studies to quantify (i) the influence of the Cross Laminated Timber (CLT) floor panels layout and (ii) one alternative load path, typically ignored in design, on the progressive collapse resistance capacity.