2.2.2. Operating Parameters

In the paper, the definition of bridge deck spacing is the vertical distance from the ceiling to the bottom deck of the double-deck bridge, as shown in Figure 2. Effective bridge deck spacing is the distance from the ceiling of the bridge to the surface of the fire resource. In this study, six different bridge deck spacings, i.e., 9.8 m, 10.6 m, 11.4 m, 12.2 m, 13.0 m, and 13.8 m, are selected and investigated, while other parameters remain unchanged. In addition, a ventilation velocity (2 m/s) is set according to the perennial wind speed in Guangzhou. As shown in Figure 1, the ventilation direction is along the *y*-direction.
