Structures / Nanning City Bridge, Quangxi, China

Address
Nanning City, Quangxi, China
Lat / Lng
22.78554, 108.78465 (click to see on map)
Year Constructed
2007
Structural Engineering Firm(s)
Structural Engineer(s)
Architect(s)
T. Y. Lin
Main Contractor
China Railway ERJU 5th Engineering Company
Media
Load Balance Diagram
Load Balance Diagram
Nanning Bridge - Night Lighting
Nanning Bridge - Night Lighting
Ling Tie Bridge 1
Ling Tie Bridge 1
Nanning Bridge 01
Nanning Bridge 01
Significance to Structural Engineering History in Northern California

Innovation by SEAONC engineers and bridge structure. The unsymmetrical dihedral angles, used 3-D shape finding based on the principle of virtual displacements to generate a statically optimal geometry and bridge form. The structure solution has the arches resist loads in primary compression, with no out-of-plane deflections or moments under gravity loads.

The bridge form evolved from understanding the geometry, mathematics and physics.

Structure Description

The Nanning Bridge over the Yong River in Nanning City, Quangxi, China is the final work of Professor T. Y. Lin. T. Y. Lin was approached by government officials in 1999 to “design” a signature landmark bridge structure for Nanning City, Guangxi Zhuang Autonomous Region. Chinese and United States firms, including OPAC Consulting Engineers, San Francisco, assisted in the engineering.

The Structure Form, which evokes a butterfly perched over the river, was conceived through study of the curved road alignment and curved through arches force diagrams, pressure lines and load balancing. The unsymmetrical dihedral angles, used 3-D shape finding based on the principle of virtual displacements to generate a statically optimal geometry and bridge form. The structure solution has the arches resist loads in primary compression, with no out-of-plane deflections or moments under gravity loads.

The 300m span bridge consists of concrete shaft foundations, concrete arch abutments, inclined steel arch ribs, curved steel box girder bridge, post tensioned arch tie inside the deck girder, and inclined steel suspension cables.

Structure Engineering includes the 3D shape finding, design of the curved post-tensioned arch bases, orthotropically stiffened steel deck and arch ribs, erection and service load analysis, aerodynamic models and evaluation, and seismic analysis, design, and detailing. The bridge design “code” used a combination of Chinese Bridge Codes and United States AASHTO code.

The bridge was opened to traffic on September 21, 2009. It illustrates that a functional, efficient, and culturally relevant landmark structure can be acheived by the application of performance based engineering principles from conception to design through construction

Interesting Facts
  • Final Bridge Structure conceived in the 60 year professional career of Professor T. Y. Lin.