Experimental collapse response of post-and-beam mass timber frames under a quasi-static column removal scenario

•Ability of post-and-beam timber frames to resist progressive collapse was studied.•Compressive arch and catenary actions under large deformations were reported.•Currently used and tested connectors cannot resist progressive collapse alone.•A proposed novel connector could represent a solution to robust timber buildings.•To resist progressive collapse, alternate load paths must be found. Mid-rise to tall mass timber buildings, which are constructed from engineered solid wood products, such as Laminated Veneer Lumber (LVL), Glued laminated timber (Glulam) and Cross Laminated Timber (CLT), have recently gained international popularity. As the height of timber buildings increases, so do the consequences of a progressive collapse event. While collapse mechanisms of concrete and steel buildings have been widely researched, limited studies have been carried out on mass timber buildings. This paper presents and discusses the experimental results performed on a series of 2D timber frame substructures, used in post-and-beam mass timber buildings and scaled down to fit the purpose of this research, under a middle column removal scenario. The behaviour of the frames and the ability of three types of commercially available beam-to-column connections and a proposed non-commercial novel connection, to develop catenary action under large deformations are reported. Furthermore, the system capacity in terms of the uniformly distributed pressure is also discussed. The test results showed that only the proposed connector was able to sustain the design pressure in international design specifications if no dynamic increase factor was considered, and therefore presented a potential solution to improve the robustness of post-and-beam timber buildings.