石臼湖特大橋, Road bridge in Jiangsu Province, China.

The Shijiuhu Bridge is a combined road and rail bridge across Lake Shijiuhu in Nanjing, Jiangsu. It is 12.6172 km long, with a 42.8 m wide road deck in two carriageways and a 17.3 m wide light-rail deck in the middle for Nanjing Metro Line S9. The rail deck runs about half a metre above the road deck, and the road deck has two median openings where the two levels meet.

The bridge was fully connected on 30 November 2014. The road deck linking Nanjing with Gaochun opened on 31 October 2015, and the Nanjing Metro Line S9 light-rail deck in the middle opened on 31 December 2017. At 12.6172 km it is China's longest lake-crossing bridge.

The bridge carries two transport modes in separate decks: the Nanjing–Gaochun highway opened on 31 October 2015, and the Nanjing Metro Line S9 light-rail track down the middle opened on 31 December 2017. The rail deck runs about half a metre above the road deck, and two openings in the central divider let road and rail decks meet at the same level for emergencies.

The bridge carries the Nanjing–Gaochun road on its two outer decks and the Nanjing Metro S9 line on the central rail deck, which runs about half a metre higher; the road is limited to 60 km/h on some sections and the metro to 70 km/h. There are no pedestrian or cycle lanes, so crossing is only possible by car or by S9 train.

The bridge deck follows an M-shaped profile, dipping at two low points where rainwater collection basins are installed. Its 8,540 drainage holes, one every 3 metres, channel runoff to these basins so that suspended solids, oil and organic matter are treated before release.