Golden Gate Bridge Seismic Retrofit Phase 3B Reaches the Main Suspension Span

The retrofit finally reached the part everyone photographs.

Phase 3B is the last piece of a seismic program the Golden Gate Bridge, Highway and Transportation District started in 1997, eight years after Loma Prieta showed how the 1937 suspension span would behave in a large Bay Area earthquake. Earlier phases hardened the Marin and San Francisco approach viaducts and the Fort Point arch. This one reaches the 4,200-foot main span, the two side spans, both 746-foot towers, the tower trusses and the south tower pier. Halmar International holds the first of two CMGC contracts at $864 million; the second runs roughly $900 million and follows immediately. Total program value is about $1.8 billion, and work started in January 2026.

Project Scope

New steel plates at the tower bases. Replacement of the expansion joints where the roadway meets the towers. Retrofit of the pylons so they can take three-dimensional movement instead of resisting it. Repainting of the south tower above roadway level. The District split the job into two construction-manager/general-contractor packages specifically so the bridge stays open through a decade of construction, which is the constraint shaping every staging and access decision on site. Contract 1 runs about six years; Contract 2 adds roughly five more, putting completion somewhere around 2036.

Why It Matters

Very few U.S. landmarks have absorbed a thirty-year seismic program, and fewer still have done it without closing. The Golden Gate carries roughly 100,000 vehicles a day across a strait with no practical detour, so the District can’t take the outages a shorter, more aggressive schedule would need. That trade, decade-long duration for continuous operation, is the model other agencies keep studying as they face the same problem on older long-span crossings.

The CMGC structure is the other reason to watch it. Splitting $1.8 billion into two preconstruction-led packages gives the District cost visibility on a job where the unknowns all sit inside 1937 steel, and it keeps a single contractor from carrying a decade of escalation risk on a fixed price.

Project Team & Details