Fire and structural performance of non-metallic timber connections

  • Daniel Brandon

Student thesis: Doctoral ThesisPhD


Recent studies showed the need for timber connections with high fire performance. Connections of members in timber structures commonly comprise steel connectors, such as dowels, screws, nails and toothed plates. However, multiple studies have shown that the presence of exposed metal in timber connections leads to a poor performance under fire conditions. Replacing metallic fasteners with non-metallic fasteners potentially enhances the fire performance of timber connections.Previous studies showed that Glass Fibre Reinforced Polymer (GFRP) dowels can be a viable replacement for steel dowels and that Densified Veneer Wood functions well as a flitch plate material. However, as the resin matrix of GFRP dowels is viscoelastic, connection creep, which is not studied before, can be of concern. Also no research has been carried out on the fire performance of these connections. Therefore, a study of the creep behaviour and the fire performance of non-metallic timber connections comprising GFRP dowels and a Densified Veneer Wood flitch plate was performed, as is discussed in this thesis.Predictive models were proposed to determine the connection slip and load bearing capacity at ambient and elevated temperatures and in a fire. The material properties and heat transfer properties required for these models were determined experimentally and predictions of these models were experimentally validated. Furthermore, an adjustment of the predictive model of connection slip at ambient temperature allowed approximating the creep of the connection. The material properties, required for the creep model, were determined experimentally and predictions of the model were compared to results of longterm connection tests.The study confirmed that timber members jointed with non-metallic connectors have a significantly improved fire performance to timber joints using metallic connections. Models developed and proposed to predict fire performance gave accurate predictions of time to failure.It was concluded that non-metallic connections showed more creep per load per connector, than metallic connections. However, the ratio between initial deflection and creep (relative creep) and the ratio between load level and creep were shown to be similar for metallic and non-metallic connections.
Date of Award24 Jun 2015
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorPete Walker (Supervisor), Richard Harris (Supervisor), Martin Ansell (Supervisor) & Julie Bregula (Supervisor)


  • timber
  • timber connection
  • non-metallic
  • GFRP dowels
  • lignostone
  • fire performance
  • interlaminar shear failure
  • creep testing

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