Changed look ahead for SF’s iconic span 

Stretches of prominent tent-like shelters will wrap around the massive cables that drape between Golden Gate Bridge towers for years while the cables are repaired and repainted.

Bridge officials are preparing to begin a 3½–year effort this summer to repaint and repair the two main cables, which contain remnants of the original 1930s lead-based paint.

Up to four crews will snake slowly along the cables inside 60-foot long, prairie schooner-style tents as they replace paint and perform maintenance work, according to chief bridge engineer Denis Mulligan.

Work will begin with a single crew working on the west side of the middle of the bridge, and up to three additional crews could be deployed as the tent-enclosed efforts move toward the shorelines, Mulligan said.

“When we start at mid-span, you’ll notice it,” Mulligan said. “It’s like a sock over a section of cable.”

The enclosed tents will protect workers from the weather and help prevent tools from falling onto the roadway.

The crews will repair frayed cable, tighten loosened bolts and replace damaged caulking at the cast-iron bands from which vertical cables are suspended at 50-foot intervals.

They will also chip away at old paint and apply a new coating.

The $30 million cable repainting project will be more painstaking and time-intensive than efforts undertaken in recent years throughout the rest of the bridge, where old paint was shorn away using high-pressure abrasive blasting.

Such blasting techniques could damage the tens of thousands of individual wires that are tightly wound together to form the main bridge cables, Mulligan said.

Work on the cables will involve the use of hand tools that are designed to remove the coating and vacuum up dislodged paint chips.

Abrasive blasting work elsewhere on the bridge has been undertaken inside depressurized plastic bubbles that helped prevent lead paint chips from escaping into the Bay or shorelines.

“Lead is great for corrosion protection, but it’s bad for flora, fauna and people,” Mulligan said.

Extensive cleanup efforts are under way on shorelines at both ends of the bridge to remove lead chips that were scattered into the environment before the dangers of lead were understood.

Work on the main cables will likely begin once crews have finished a similar two-year recoating project on the bridge’s vertical suspenders and could last for 3½ years.

Depending on the weather, work on the vertical suspenders is expected to finish in May or June, Mulligan said.

Site for sore eyes

- Bridge color: Orange vermilion
- CMYK colors: Cyan 0%; magenta 69%; yellow 100%; black 0%
- Pantone Matching System color: Code 173
- Color selected by architect Irving Morrow in part because it blends with the span’s natural setting
- Color is also known as “international orange” and is easily seen from passing ships
- Navy originally wanted bridge painted black with yellow stripes for increased visibility

Source: Golden Gate Bridge Highway and Transportation District

A golden link

- 73 years: Age of Golden Gate Bridge
- 2: Anchored cables from which the Golden Gate Bridge is suspended
- 7,650 feet: Length of each cable
- 27,572: Wires wound together to form each cable
- 40,000 miles: Length of wire in each cable
- 45 inches: Diameter of each cable
- 68 percent: Lead content of original paint
- 250: Pairs of suspender ropes that hang vertically from main cables

Source: Golden Gate Bridge Highway and Transportation District

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A daily newspaper covering San Francisco, San Mateo County and serving Alameda, Marin and Santa Clara counties.
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Wednesday, Mar 21, 2018


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