What's the appropriate 75th anniversary gift for a bridge that seems to have everything? It has looks, personality, a colorful past, and a bright future. For the Golden Gate Bridge, recognized worldwide as an iconic symbol of that special "City by the Bay," the answer was a spectacular light and fireworks show over San Francisco Bay in late May 2012.
The concept for the celebration was a collaborative effort among dozens of people, including producer Foghorn Creative, lighting designer Lightswitch, Golden Gate National Parks Conservancy, and the Golden Gate Bridge, Highway and Transportation District. Once the general concept was developed, San Francisco stage electrician Dave Hatch was brought on board as production electrician and technical director.
Securing lights on rough waves
The lighting portion of the show included the Golden Gate Bridge, a barge in San Francisco Bay, and a music and food festival along the shoreline. Approximately 100 people were involved in just the lighting part of those venues. The bridge and the barge each had their own crews. All the barge lighting equipment and generators were loaded onto the barge by crane in one day, leaving seven days and nights for cueing and rehearsing the show. The lighting crew on the barge, working in sometimes turbulent conditions, had to secure all the lights and a freestanding 17-foot-tall truss structure that was used to hang a moving nine-foot mirror ball.
The bridge setup had its own set of challenges, because the bridge lighting crew had to work around a strict time schedule for a partial bridge closing. But before they even got to the bridge they had to find the right generators. "We had to find generators that could supply enough amperage and still meet weight and size requirement," recalls Hatch. "Then we had to design and build platforms for the generators to distribute the weight to meet the per square foot requirements."
Working around wind, cars, and bicyclists
Probably the biggest challenge was how to get all the equipment onto the bridge. The bridge crew used cranes to load all the equipment onto the sidewalk of the bridge and then secured it to the railing, because they had to contend with high winds that first night. Because the sidewalk was open for bicycle traffic during the day they also had to provide safety fencing for all areas.
Setting up the power for the bridge lighting was pretty straightforward. Once the generators were connected, technicians "ohmed out" all the generator ground jumpers to the bridge structure to make sure they had a solid connection. Then, for the next six days, the lighting crew worked feverishly setting up and cueing the show and coordinating a dress rehearsal with the barge side of the show.
The barge lighting control was sent via FSK (frequency-shift keying) and then turned into DMX (digital multiplexing), which worked well once the barge came within range of the transmission antennas and the control locked on. The bridge lighting was controlled via wireless DMX, which required line-of-sight for the high-gain antennas. The narrow degree angle of the receivers and transmitters was affected by the high winds and, perhaps, reflection and interference from the bridge structure and traffic. About an hour and a half before the show, once the traffic was off the roadbed, the control system stabilized and remained so for the entire show.
"We did have a system in place for the techs to run the show locally at their respective locations if we couldn't solve the problem, but fortunately we didn't have to go to the backup plan," says Hatch.
Lighting the lights
There were five separate areas of lights on the bridge, each powered by its own generator and managed by its own technician. Another technician oversaw the moving lights and generators for the bridge as a whole. Most, if not all, of those techs used various Fluke digital multimeters to check voltage and frequency at initial fire-up. Then they used a variety of Fluke clamp meters to verify amperage and phase balance once the lights came on line. After the system was up and running they continued to check the voltage and amps at regular intervals throughout the show.
And what a show it was. Seventy-five 7000-watt high intensity moving lights were used to create the illusion of candles. "At one point on the barge, 50 lights were splayed into a many-colored fantail that emulated the 'Scintillator' of the Panama-Pacific International Exposition of 1915," says Hatch. The Scintillator was a battery of searchlights on a barge in San Francisco Bay that beamed 48 lights in seven colors across the famous fog banks.
Just after dark on May 27, 2012 the light show started with a dramatic bridge lighting and continued to blend lights between the bridge and the barge with a spectacular pyrotechnic display. All the planning, prep, and monitoring time paid off.