Long Bridge

Long Bridge
龙桥特大桥
Xuan'en, Hubei, China
623 feet high / 190 meters high
879 foot span / 268 meter span
2015

Leaping between two cliffs in a densely forested canyon, the Long Bridge makes for a picture perfect scene on the S89 Enshi to Qianjiang expressway that opened in 2014 between Hubei and Chongqing provinces.

With a central span of 268 meters, the Long Bridge is another one of China's popular CFST or concrete filled steel tubular arch. First used in 1990, this is now a popular method to build steel arches throughout China's mountainous west, especially when crossing a deep crevasse or gorge.

The eight large steel tubes that run along the underside of the Long arch were initially hollow. Once the arch was closed, concrete was pumped into these tubes from the bottom up. Depending on the length of the span and the width of the bridge, different styles of tubing are used. For Long, they adopted an array of single tubes spaced apart from each other. Other configurations include dumbbells with two tubes closely connected, a mix of a dumbbell and single tubes such as was done on the Beipanjiang River Railway bridge or a tight cluster of tubes known as “multiple contiguous”. Once hardened, the concrete solidifies and stiffens the arch, improving the compressive strength of the entire structure.

The main span of 268 meters has a span to rise ratio of 5:1. The two main arch ribs are connected by X braces that are empty steel pipes. The deck is 24.5 meters wide.