With its 185-metre central span and 55-metre secondary spans reaching to the riverbanks, the Chengdu West First Bridge is a road, cycle and pedestrian bridge over the meandering Jiangxi River; enabling the West Line Road to become the western section of the Airport New Town ring-road and cycle route.
As arches provide the most efficient bridge structure for spans between 120-250 metres, this symmetrical bridge is composed of two primary steel arches that rise from either side of the road deck. As they rise, the arches lean together to touch tangentially at their crown, stabilising the structure from lateral wind forces.
The dynamic curvature of the bridge’s supporting piers and abutments taper into its primary arches and road deck, defining a sculptural landmark within Chengdu’s transport infrastructure.
Commissioned to build the bridge following the 2019 design competition, Zaha Hadid Architects (ZHA) used structural analysis software on the design’s digital model. Examining all material self-weight, superimposed dead load and traffic live loading, as well as environmental considerations of wind and temperature, this analysis ensured the structure and foundations have been designed to exceed the standards required for once-in-200-year weather events.
With a height to span ratio of approximately 1:6, the bridge’s arches rise to 30 metres and are tied together at their base by longitudinal box girders that run along the edge of the road deck. These ties resist the outward horizontal thrust of each arch and significantly reduce the horizontal loads on the bridge’s foundations.
Concrete abutments at either end of the bridge incorporate connectors linking the road deck to the West Line Road’s surface. With no foundations positioned in the Jiangxi River, intermediate piers are located beneath the springing points of the arches on each riverbank.
The bridge’s bored piles and abutments were constructed using conventional in-situ reinforced concrete techniques. The steel box sections of each arch were prefabricated in optimal dimensions for transportation and assembly on site. The edge box girder sections within the road deck include the cable anchorages. These sections were also prefabricated and delivered in sections to be spliced together with on-site welding.
The bridge’s prefabricated plate cross girders were delivered to the site and connected to the edge girders by a bolted cover plate splice connection. The concrete road deck has been constructed from precast panels fixed to the cross girders by in-situ concrete stich pours.
Mobile cranes lifted all prefabricated steelwork and precast concrete elements within the bridge’s short assembly schedule. The Chengdu West First Bridge crossing the Jiangxi River will open to the public on completition of the West Line Road.