The phoenix-shaped Beijing Daxing International Airport has become an iconic building in the Chinese capital.

Designed by Zaha Hadid Architects, ADP Ingénierie and Beijing Institute of Architectural Design (BIAD), the terminal building has a total Gross Floor Area (GFA) of over 700,000m² and can process 100 million passengers every year, relieving pressure on the Beijing Capital International Airport.

Daxing is designed to be a super transportation hub for Beijing. Three underground rail stations with a total area of 200,000 m² are situated below the terminal building, with five railway lines giving passengers transport links for onward travel. 

BIAD appointed us as fire engineering consultants for the entire airport, and later asked us to peer review and value engineer the steel roof structure for the Beijing New Airport Construction Headquarters. 

The flowing, interconnected form of the terminal is a stunning piece of architecture, but it poses huge design challenges in terms of fire safety. This is complicated by the transportation hub beneath and the interconnecting spaces, which had to be treated as a single massive fire compartment. 

Our fire engineers took a performance-based approach to designing the fire control zones for the airport. We incorporated a series of fire protection strategies, including smoke curtains, fire shutters and fire separation bands to prevent the spread of fire and smoke from one zone to another, replacing traditional solid walls that affect passenger circulation. 

High risk areas are fully contained with fire resistant construction, and we used the large Central atrium to control smoke by using buoyancy and dilution.

Beijing Daxing International Airport. Credit: Zhou Rougu Photography
The flowing, interconnected form of the terminal is a stunning piece of architecture, but it poses huge design challenges in terms of fire safety.
Beijing Daxing International Airport. Credit: Zhou Rougu Photography
We incorporated a series of fire protection strategies to prevent the spread of fire and smoke from one zone to another, replacing traditional solid walls that affect passenger circulation.

A smart exit strategy

Emergency exits presented a major design challenge. Due to the size and the number of occupants, escape distance to the outside is over 200m for most parts of the Central zone, compared to a standard building where it should be under 75m. To mitigate this, we provided 29 exit stairways in the Central zone, shortening the travel distance for various floors and diverting pedestrian flow to prevent bottlenecks. 

The baggage handling areas in arrivals also posed risks for swift evacuation, so we designed a smart exit strategy for public zones using different routes for evacuation depending upon where any fire may be located.

Strain energy density in the original scheme and optimised scheme at the northwest wing (top) and Central zone (bottom)

Optimising the roof structure

The roof of the terminal building is a large-span, complex hyperboloid steel grid structure covering over 350,000m². Containing more than 170,000 steel members, it is supported by giant C-shape columns that seamlessly connect with the roof.

Our engineers, using software developed in-house, studied the configuration, loading, vertical support system reactions and the structural deflection and displacement across the roof. 420 load combinations were considered and 38 different cross section sizes were employed in the superstructure, with our analysis showing significant scope for optimisation. 

With extensive experience in long span steel structures and structural design, our engineers proposed strategies for the different zones of the terminal, improving roof truss patterns and reducing unnecessary structural depth and member sizing.

Efficiency is the key

Although the design of the steel roof had already been reviewed by several local design institutes prior to our review, Arup’s comprehensive optimisation strategies helped the project achieve a further reduction in steel tonnage, resulting in significant cost savings and reduced carbon emissions. 

By integrating the transportation hub and terminal building instead of placing them at separate locations, our solution will help save over 1.6 million hours for nearly 30 million passengers every year.

Beijing Daxing International Airport. Credit: Zhou Rougu Photography
Arup’s optimisation helped reduce steel tonnage, resulting in significant cost and carbon emission savings for the project.

Did you know?

700,000

m2

GFA

100

m

annual passengers at maximum capacity

170,000

steel members for the signature rooftop