Golden Gate Bridge Seismic Retrofit Enters $864M Phase
Golden Gate Bridge seismic retrofit work has entered its final major construction phase, with an $863.9 million contract covering the landmark’s two towers and side spans. The Golden Gate Bridge, Highway and Transportation District says work will continue while the bridge remains open, with weeknight lane closures beginning Oct. 5.
Key Takeaways
- Phase 3B of the Golden Gate Bridge seismic retrofit is scheduled to run from 2026 through 2036
- The first construction contract is valued at $863,949,008 and covers the north and south towers and side spans
- Work includes tower-base reinforcement, truss strengthening, floor-beam retrofits, lateral bracing and energy-dissipation devices
- Weeknight lane closures are scheduled to begin Oct. 5, while vehicle traffic is expected to continue in both directions
- The current phase follows decades of seismic work prompted by engineering reviews after the 1989 Loma Prieta earthquake
Golden Gate Bridge Seismic Retrofit Enters $864 Million Phase
The Golden Gate Bridge seismic retrofit is moving through the final phase of a program that has been underway for decades. Phase 3B covers the main suspension span, the two main towers, the south tower pier and the side spans, with the overall phase scheduled from 2026 through 2036.
The first construction contract was approved at $863,949,008 for Halmar International, district records show. The contract became effective in December 2025, and the district issued a notice to proceed effective Jan. 5, 2026.
That contract concentrates on the two towers and the north and south side spans. The district says this work comes before the main span because the towers and side spans are less flexible and require a different strengthening sequence.
The scale of the project adds a lengthy construction program to a bridge that remains a heavily used transportation corridor. The district says the 1.7-mile structure serves up to 40 million vehicles annually. The span also remains one of the most recognizable San Francisco city landmarks for residents and visitors.
The first contract is expected to take approximately six years. A second consecutive construction contract is planned as the district completes the remainder of Phase 3B.
Retrofit Work Targets Towers, Roadway and Structural Movement
Much of the construction will take place on components that are difficult to see from the roadway. District plans call for large steel plates at the tower bases, stronger tower trusses and replacement of expansion joints where the roadway meets the towers and pylons.
The broader Phase 3B design includes reinforcing lateral bracing, retrofitting 255 floor beams and installing 38 energy-dissipation devices. The district describes those devices as a way to reduce the amount of seismic energy transferred into the bridge during strong shaking.
Contract documents outline additional work on suspender-rope supports, cross struts, roadway support systems and other structural connections. The South Tower above the roadway is also scheduled to be cleaned and repainted as part of the project.
Earlier phases strengthened the Marin and San Francisco approaches, anchorage structures, Fort Point Arch and nearby pylons. Phase 3A, completed in 2014, focused on the north anchorage housing and Pylon N1.
The broader program traces back to engineering reviews conducted after the 1989 Loma Prieta earthquake. The Golden Gate Bridge had no observed damage from that earthquake, but the event led the district to examine how the structure could perform during stronger shaking closer to the crossing.
The district says the bridge can safely withstand a large earthquake in its current condition. Phase 3B is intended to reduce the potential for significant damage to the main suspension structure and improve the bridge’s ability to remain in service following a major seismic event.
National Park Service information similarly describes the Golden Gate Bridge as undergoing work intended to strengthen it for a magnitude 8-plus earthquake scenario. The current phase focuses on structural performance rather than correcting an immediate operating problem.
Weeknight Lane Closures Begin Oct. 5 as Bridge Stays Open
The first October traffic changes tied to the project begin Monday night, Oct. 5. The district says one southbound lane and two northbound lanes will remain open from 9 p.m. to 5 a.m. on the nights of Oct. 5 through Oct. 8.
No seismic-related lane closure is scheduled for Friday night, Oct. 9. The district says the bridge roadway will remain open to vehicle traffic at all times during the announced work, although motorists may encounter slower traffic near construction areas.
Keeping the crossing operating is a major logistical factor. Engineering News-Record reported during preconstruction that project teams also had to account for vehicle traffic, pedestrians, cyclists and ongoing bridge operations while planning access for construction crews.
The work comes as bridge costs and maintenance needs remain closely watched across the region, including separate changes affecting Bay Area bridge tolls on crossings outside the Golden Gate system. The Golden Gate Bridge is operated separately by the Golden Gate Bridge, Highway and Transportation District and has its own toll structure.
For drivers, the near-term effect of the seismic work will be temporary overnight lane reductions as crews advance through the first construction contract. The broader Golden Gate Bridge seismic retrofit is scheduled to continue in stages through 2036.
Frequently Asked Questions
What is the Golden Gate Bridge seismic retrofit?
The Golden Gate Bridge seismic retrofit is a multiyear program designed to strengthen the crossing against major earthquake forces. Phase 3B focuses on the main suspension structure, two towers, side spans and south tower pier.
How much does the current construction contract cost?
The first Phase 3B construction contract is valued at $863,949,008. It covers seismic work on the north and south towers and the two side spans.
Will the Golden Gate Bridge close during the retrofit?
The district says the roadway will remain open to vehicle traffic during the currently announced work. Beginning Oct. 5, overnight lane reductions will leave at least one southbound lane and two northbound lanes open during the scheduled construction periods.
When is the seismic retrofit expected to be finished?
Phase 3B is scheduled from 2026 through 2036 and is divided into two consecutive construction contracts. The first contract is expected to take about six years before additional work proceeds under the second contract.
