Abstract: This paper addresses the specific fire protection requirements for vehicle depot superstructure development projects. In accordance with the mandatory requirement in the Standard for fire protection design of metro that the fire resistance rating of floor slabs should not be less than 3.00 h, a fire resistance performance test was conducted on reinforced concrete roof slabs using a passenger vehicle depot superstructure development project as a case study. Three types of reinforced concrete slab specimens with varying dimensions and span-to-thickness ratios were designed. Using a scaled-down load method under standard heating conditions, tests evaluated their load-bearing capacity, integrity, and thermal insulation. Test results indicate: All specimens withstood the 181 min standard fire test without failure. Among them, the two-way slab specimen demonstrated optimal performance, with a maximum average temperature rise at the unexposed side of 47.5 ℃ and a maximum deflection of 91.1 mm, significantly below code limits. Although unidirectional slab specimens exhibited greater deflection (310.3 mm) during testing, their deformation rate remained within limits, and the single-point temperature rise at the unexposed side (148.1 ℃) still met code requirements. This study confirms that under specific design parameters (slab thickness ≥170 mm, protective layer thickness 35 mm, load ratio approximately 71%), this type of reinforced concrete roof slab can meet the 3.00 h fire resistance rating requirement. Its superior performance is primarily attributed to the substantial slab thickness, protective layer thickness, and the film effect formed in the two-way slab.

Key words: roof slab, scaled experiment, Fire resistance performance, fire resistance rating