Experimental investigation into fire performance of mixed species glulam beams under three-side fire exposure

The fire performance of glulam beams of high-quality structural materials was examined in this study. Beam specimens of different wood species were subjected to different fire durations and their tension-zone (bottom) fire performance and residual bearing capacity were measured. The charring rate of the Chinese fir glulam beam mixed Douglas fir and larch wood in the tension zone was lower and its residual bearing capacity higher than a pure Chinese fir glulam beam. A set of residual section calculation results was compared with the test values to determine their feasibility in evaluating the fire performance of mixed species glulam beams. The error between the test and calculated values was less than 10%. This research could achieve effective use of low-quality fast-growing wood (Chinese fir) and save costs. In addition, the residual bearing capacity of these beams was increased by 69.1–245.4% compared with Chinese fir glulam beams.