Comparison of the response to local fire of beams made of wood-CFRP composite (BSH-CFRP) and glue laminated timber (BSH)

The project included local combustion of 24 beams with structural dimensions made of wood-CFRP composite (BSH-CFRP) and glue laminated timber (BSH) under a constant load, in a three-point bending, in the most loaded cross-section – in the middle of the beam. The effort of each sample was 90% of the GL24h wood bending strength. According to the calculations, the reinforced beams (BSH-CFRP) required applying a much higher force than the beams without reinforcement (BSH). The dimensions of the cross-sections were determined based on the available CFRP tapes (widths 100 mm, 120 mm, 150 mm), FEM calculations, the maximal force that could be provided on a self-designed and self-constructed pilot test stand and the burning time, during which it was possible to keep a proper flame. In order to get statistically valid results, 4 specimens were tested for each cross-section. The following parameters were measured - combustion time up to the beam destruction, the deflection increment and the temperature of the sample during fire. Summarising the got results, a certain trend is clearly noticeable, which shows that CFRP tapes used inside the cross-section can increase the fire resistance of wooden girders. However, the tapes must be positioned in the way that they are protected by the wood during the fire exposure. In this study, it was provided by the appropriate cross-section width. With small widths or too small distances of CFRP tapes from the cross-section edge, the fire resistance may be reduced comparing to non-reinforced elements. It is worth noting that the failure behaviour of the beams without and with the CFRP tape was different. The former cracked rapidly, while the latter showed some ductility.Provided datasets include results for 24 beams (*.ZIP), which contain measurements of deflection, temperature, and time. The additional file presents tables with initial analysis of the data (*.ZIP).