Abstract: Experimental tests were carried out to study the fire?resistance performance of cross?laminated timber floors with full?scale size in load?bearing conditions. The tested floor specimens were 175 mm in thickness, and loaded with averagely?distributed weight of 2.0 kN/m2. The two tested floors were made using heat?resistant PUR adhesive and ordinary PUR adhesive, and protected with one?layer of 15 mm?thick fire?resistant gypsum board and two?layers of 12 mm?thick fire?resistant gypsum boards. Test results show that, for the floor specimen using heat?resistant PUR adhesive and protected with one?layer of 15 mm?thick fire?resistant gypsum board, the gypsum board fell off at about 45~55 min, and no obvious char layer delamination was observed. For the floor using ordinary PUR adhesive and protected with two?layers of 12 mm?thick fire?resistant gypsum boards, the 1st layer of gypsum board fell off at about 30 min, and the 2nd layer fell off at about 60 min, and the char layer delaminated at about 85~110 minutes. At 121 minutes, the vertical displacements at the center of floor specimens were about -25 mm and -33 mm, respectively. The unexposed sides of the floors showed intact, and the temperature rise on the unexposed sides were less than 2 ℃ for the both specimens. The final results show that the fire resistance rating of two tested floors is not less than 2.00 h.

Key words: cross?laminated timber floor, full?scale test, load?bearing, fire?resistance performance, charring rate