Aizhai Bridge: World’s Highest Tunnel to Tunnel Bridge
Aizhai is the world’s highest tunnel to tunnel bridge and the fourth suspension bridge in China to cross a valley so wide it seems to be connecting two mountain ranges. The first three were the Siduhe, Balinghe and Beipanjiang 2009 bridges. Of the world’s 400 or so highest bridges, none has a main span as long as Aizhai with a tower to tower distance of 3,858 feet (1,176 mtrs). Located deep in the heart of China’s Hunan Province near the city of Jishou, the suspension bridge is the largest structure on the Jishou to Chadong expressway with a deck 1,102 feet (336 mtrs) above the DeHang Canyon.
The two tunnels on either side of the Aizhai bridge allowed the engineers to use the mountain top for the location of one of the towers, reducing its height to just 165 feet (50 mtrs) – unusually short for a bridge with a span nearly as long as the Golden Gate bridge at 3,858 feet (1176 mtrs). In addition to cost savings, the stubby support also allows the bridge to blend more naturally into its surroundings. The taller bridge tower is no less unique with side span cables that soar down the backside of a mountain, making first time visitors quizzical as to what exactly lies ahead. With most of the structure hidden from view, the bridge will come as a jaw-dropping surprise whether you enter the canyon from either tunnel. Due to a gap of approximately 328 feet (100 mtrs) between the last truss suspenders and the tops of the bridge towers, the engineers added some additional ground anchored suspenders to stabilize the two massive suspension cables and reduce any oscillations that could damage other components of the bridge. An overlook and visitors center will offer additional views of the broad valley.