San Francisco International Airport (SFO) is embarking on a mission to preserve and modernize its historic 1969 Superbay Hangar, a critical piece of aviation infrastructure that has served global airline fleets for over half a century. The $132 million project, which includes a $97 million construction budget, represents a sophisticated approach to facility management, blending historical preservation with cutting-edge sustainable engineering.
To navigate the complexities of renovating a high-security, 24/7 operating facility, SFO has engaged a team led by the HCI/InnoActive joint venture, with STV serving as a major subconsultant. This progressive design-build (PDB) effort is not merely a renovation; it is a strategic maneuver to extend the service life of one of the nation’s few facilities capable of housing four Aircraft Design Group V (ADG-V) wide-body aircraft simultaneously.
The Vital Statistics: A Masterpiece of Aviation Infrastructure
The Superbay Hangar is a massive, irreplaceable asset within SFO’s real estate portfolio. As a facility capable of accommodating four of the largest commercial aircraft in the world, its operational status is vital to the maintenance workflows of major carriers, including United Airlines and American Airlines.
- Project Budget: $132 million total, with $97 million allocated specifically for construction.
- Duration: The contract is structured for 1,095 consecutive calendar days from the Notice to Proceed.
- Facility Status: Currently undergoing initial programming and design, with early site investigations and risk mapping underway.
- Scope: Structural retrofitting, system electrification, code compliance upgrades, and seismic performance improvements.
Chronology of a Complex Delivery
The project is currently in the "programming and design" phase. Because the project utilizes a progressive design-build framework, the timeline is intentionally fluid. Rather than setting rigid, arbitrary milestones that fail to account for the realities of aging infrastructure, the team is prioritizing discovery.
Phase 1: Programming and Site Investigation
The current phase focuses on "risk mapping." Because the facility dates back to 1969, the team is operating under the assumption that many structural conditions—foundations, lateral systems, and hidden utilities—are only partially documented. By using laser scanning, investigative demolition, and forensic engineering, the team is uncovering the "unknowns" before they become expensive change orders.
Phase 2: Design and Phasing
Following the investigation, the team will develop a phasing plan. This is perhaps the most critical step, as construction must occur in lockstep with the needs of the airlines using the hangar. The design will be tested against operational constraints to ensure that construction crews can work while airline mechanics continue their high-security, around-the-clock maintenance checks.
Phase 3: Construction and Commissioning
The final construction phase will span the remainder of the 1,095-day timeline. The project will transition from foundational structural work to systems installation—specifically, the conversion of legacy energy systems to full-electric, in alignment with SFO’s sustainability goals.
The Progressive Design-Build Advantage: A Risk-Reduction Strategy
The decision to use the progressive design-build (PDB) method is a calculated response to the volatility of renovating large-scale, older buildings. In traditional project delivery, design is often advanced in a vacuum, which can lead to significant friction when the builder encounters conditions that the designer did not anticipate.
Henry Dumaran, STV vice president and aviation regional director, emphasizes that PDB is fundamentally a risk-reduction strategy. "SFO’s use of progressive design-build reflects the airport’s broader commitment to Exceptional Project Outcomes 2.0," Dumaran stated. "Rather than advancing design in isolation and transferring uncertainty downstream, SFO’s approach brings the owner, designer, builder, trade partners, and key stakeholders into the same problem-solving environment early enough to influence scope, means, and methods."
This collaborative environment allows the team to:
- Evaluate multiple structural intervention strategies without being tethered to a pre-set, potentially incorrect, design.
- Analyze temporary works to ensure that structural reinforcement does not impede the movement of heavy aircraft.
- Align stakeholder expectations regarding cost, schedule, and operational continuity before the final commercial terms are locked in.
Official Perspectives: Balancing Innovation and Continuity
SFO spokesperson Doug Yakel has been clear about the challenges the project faces. "SFO selected progressive design-build because of the complexity and uncertainty associated with renovating a large-scale, older facility while it remains operational," Yakel noted. "With a facility of this age and scale, understanding existing conditions and how they affect the design, construction approach, cost, and schedule will be a critical part of the project."
The "zero-tolerance" operational constraint is the defining characteristic of this project. Unlike a standard commercial office renovation, the Superbay Hangar cannot simply be cordoned off. The work must be surgical, occurring directly around active airline schedules.
"Maintaining the Superbay Hangar’s operational capability is one of the project’s fundamental requirements," Yakel added. "For that reason, operational planning and construction phasing will be a critical focus throughout the project."
Sustainability: Paving the Way to Net-Zero
One of the most ambitious aspects of the project is the alignment with SFO’s long-term environmental objectives. The airport has committed to reaching net-zero carbon operations, and the Superbay Hangar modernization is a key pillar of this strategy.
Instead of opting for a carbon-intensive demolition and reconstruction process, SFO is choosing to revitalize the existing shell. By upgrading the building’s energy systems and transitioning the facility to full electric power, the project team will significantly lower the facility’s carbon footprint.
"Given the age of the facility, this project offers a significant opportunity to improve the energy performance through electrification," Yakel explained. "The project team will evaluate strategies for improving the performance of the existing facility while considering constructability, operational requirements, lifecycle value, and SFO’s broader long-term sustainability objectives."
Technical Challenges of Legacy Architecture
Modernizing a 1969 structure requires more than just new paint and electrical wiring. The "Superbay" design involves massive structural spans that present unique challenges in modern seismic code compliance.
As Dumaran points out, legacy buildings often conceal structural "surprises." These include:
- Undocumented modifications: Previous repairs or minor upgrades made over the last 50 years that were never properly logged in the building’s original schematics.
- Hazardous Materials: Legacy buildings often contain materials that must be safely abated before structural retrofitting can begin.
- Utility Interfaces: Integrating modern high-efficiency HVAC and electrical systems into a framing structure designed for 1960s-era utility standards.
By bringing the project delivery partner to the table early, the team can "shape the design around what is actually buildable." This proactive stance prevents the common pitfall of designing a technically perfect solution that is physically impossible to install in a congested, 24/7 operating environment.
Implications for the Aviation Industry
The SFO Superbay Hangar project serves as a case study for airports globally. As the aviation industry faces pressure to increase capacity and meet strict sustainability mandates, the temptation to "tear down and rebuild" is often high. However, the SFO model demonstrates that with the right procurement method and a collaborative team, legacy infrastructure can be transformed into a modern, high-performance asset.
By keeping the hangar operational, SFO avoids the massive logistical cost of displacing airline maintenance operations, which would otherwise force carriers to reroute aircraft to other cities for service. This project ensures that San Francisco remains a central hub for global aviation, capable of handling the most advanced aircraft in the sky, while simultaneously honoring the principles of sustainable development and fiscal responsibility.
As the project moves from its current programming phase into detailed design, the eyes of the construction and aviation sectors will remain on SFO, observing how this ambitious blend of old-world steel and new-world technology comes together to define the future of airport infrastructure.
