Context-Sensitive Design Means Complex Bridges Match Their Environment

Daniel K. Inouye International Airport is the site of three pedestrian bridges built in the early 1970s to span four lanes of elevated roadway and connect the overseas parking structure to the overseas terminal. Decades of use and exposure to environmental factors deteriorated the structures. As part of a vision to elevate Honolulu’s status as an international hub, the Hawaii Department of Transportation, Airports Division sought to replace the bridges.

HDR has supported the project since 2014, from concept to final design, including architectural services, structural engineering and construction administration. The context-sensitive replacement design retains the terminal’s character and complements other ongoing modernization projects.

A Welcoming Space for Travelers

The steel bridges’ design recognizes the importance of creating a welcoming space for travelers and matching the airport’s open-air aesthetic, while also providing more space than the previous bridges. The restrained materials palette allows the wood ceiling’s Hawaiian-inspired geometric pattern to become a focal point. Full height glazing creates a feeling of openness while filling the space with natural light. Vertical mullions were omitted from the facade to accentuate views and allow cool trade winds to permeate the staggered planes of glazing, keeping travelers comfortable and dry in rainy conditions.

At the same time, the wider and taller bridges allow for an increased passenger flow anticipated from a forthcoming direct connection to the planned Honolulu Authority for Rapid Transportation Airport Station.

Adapting to Technical Challenges

Flexibility became important on the project when the stakeholders requested key changes to the bridges’ design, removing a center support column. Improvements to the existing mid-columns were deemed too disruptive to airport operations. A contractor had already been retained for construction and a swift solution was needed to keep the project moving forward. A previous light detection and ranging survey had been used to capture data on the location of everything surrounding the aging bridges, from physical buildings to palm trees. This information was used in 3D models to match the bridges’ design to airport conditions and be as technically accurate as possible. As designers adjusted to replace the center column with supporting end columns, this data meant that changes could be made more quickly and with confidence in their accuracy.

Each 175-foot-long bridge had additional unique design challenges; the Ewa Bridge requires design provisions for a future escalator, the Mid Bridge has a tight roadway clearance, and the Diamond Head Bridge must support and conceal chilled water lines. The bridges’ design addresses the challenges with aesthetic consistency and maximizes economies of scale.

The lack of required maintenance is also noteworthy. The project team selected long-lasting, low maintenance materials for the harsh marine environment, including the bridges’ interior and lobbies. A hydrophilic, self-cleaning coating on the glazing reduces the need for periodic window washing.

To limit loads to the roadway during construction, the bridges are designed in three segments to be individually lifted into place with a mobile crane. Completed in 2021, the bridges were finished in stages to reduce impacts to airport operations. As they opened for use, airport visitors were rewarded with a more modern, safe, pleasant experience consistent with the airport’s status as an international hub.