Chongqing is famous for its hot Sichuan dishes and nearby religious cliff sculptures, but China’s fourth most populous city is also known for the record-breaking scale and sweeping artistry of its new bridges spanning the mighty Yangtze River. Junling (John) Sun, chief engineer of two of the most innovative bridges over the Yangtze in Chongqing, received a Ph.D. in structural engineering at UC San Diego. He studied under Frieder Seible, dean of the Jacobs School of Engineering, an internationally acclaimed bridge designer.

Seible advises Sun on his bridge projects around the world, including the new Caiyuanba Bridge (see below), which carries six lanes of vehicle traffic and two pedestrian walkways on its upper deck, and two monorail tracks on the lower deck. The new bridge, a transportation backbone in the city of 30 million residents, connecting two thriving business districts on either side of the Yangtze, is the largest tied-arch span in the world that carries both highway and rail traffic. A cable is attached, or tied, to join the bottom ends of the arch, like the string of a giant bow.

Sun also was the chief engineer for the design of the ShiBanPo Yangtze River Crossing in Chongqing. This one is a much sleeker girder design that carried vehicle traffic. The main span, an innovative design, is a stunning 330 meters, which was thought to be technologically impossible to achieve and has a hybrid steel-concrete design. The middle third of the ShiBanPo main span is steel, which is much lighter than the concrete used in the remainder of the girder section.

“The 300-meter length for a girder span was almost a psychological barrier to bridge designers until Junling devised an innovative way to achieve an even longer span,” says Seible. “When I look at the ShiBanPo’s main span it looks to me like a giant wing soaring above the river.”

—Rex Graham

View more Class Notes online & submit your own!
If you have not yet registered, you'll need to create a user name and password. MORE