Lighting infuses new life into a beloved Minneapolis landmark.

» Residents near the falls of St. Anthony, the only waterfall on the Mississippi River, are witnessing the greatest boom along the riverfront since the milling days of the late 1880s, when Minneapolis became 'flour capital' of the world. People are flocking to this historic waterfront district to live in restored buildings or in new condominium towers and townhouses. Numerous pedestrian walkways blanket the area, but the most popular by far is the route along the Stone Arch Bridge.

A working bridge until 1965, the 123-year-old structure was completed in 1883 by railroad pioneer James J. Hill. Deemed a National Historic Engineering Landmark in 1975, rehabilitation started in 1980, and in 1994 the bridge was restored for pedestrian use. Below the bridge deck, 22 arches of native granite and limestone stretch across the river spanning the Falls of St. Anthony. However, by night, lack of any bridge illumination, except for the pedestrian walkway above, made this section of the Mississippi a dark void; a gloomy contrast to the warm glow of light from the neighborhoods bordering the river.

In 2003, when planning began for the 'Grand Excursion 2004' celebration-a river and steamboat flotilla replicating the 1854 Grand Excursion route up the Mississippi from the Quad Cities of Iowa and Illinois to the Twin Cities of Minneapolis and St. Paul-Peggy Douglas, chief developer of the Minneapolis historic district, realized the city's riverfront could be revived by lighting the bridge arches. Subsequently, city mayor R.T. Rybak brought Douglas together with Jay Cowles and Charles Zelle, who had founded the Friends of the Minneapolis Riverfront while working on the Grand Excursion organizing committee. In order to fund the project (no public monies were available), Cowles and Zelle's fundraising efforts generated $545,000, enough to light the 12 main arches over the water. Meyer, Scherer & Rockcastle, well known for its design of the award-winning Mill City Museum adjacent to the site, was chosen as the architecture firm to oversee the project.

With Tom Meyer as principal, the firm's lighting designer, Carla Gallina, worked closely with the Minnesota Department of Transportation (MnDot), the bridge's owners; the Minneapolis Heritage Preservation Commission; and a host of other governmental agencies. David Fey, the city's senior policy manager, helped navigate the bureaucratic red tape, which involved no less than seven different public and private entities. The overall goal of the bridge's illumination was to enhance the warm natural color and texture of its limestone, and to highlight the arches' sculptural beauty without reflecting light into the adjacent neighborhoods. 'We had three options,' explains Gallina. 'Light the river faces, light the arches, or light the river faces and the arches.'

The MnDot required that the lighting design for this landmark be reviewed under the National Historic Sites Act, and conseqently, the team had to meet three strict requirements: no drilling or damaging of the stone, no exposure of the conduits, and replace any damaged mortar joints with a historically correct mix. The contour of the stone had depths varying from 8 inches to 2 feet, so the designers needed to find a mounting system that did not touch the stone. The solution placed a single bracket along the mortar joint, which in turn was secured with a bolt. The team worked with a bridge inspector and mortar expert to review each mounting location to ensure there was no damage. Next, to avoid drilling and exposing the conduit, they used existing trench and drain holes to bring the conduit to the fixtures.

The team's lighting approach was straightforward-find the smallest fixtures and use as few as possible. An asymmetric uplight from Elliptipar for use with a 400W high-pressure sodium lamp was selected. The luminaires, 24 in total, could not be located at the bottom of each arch because there was no way to maintain them in case of flooding. Instead, Gallina placed the fixtures-2 per arch, one on each side and cross-aimed-about one-third of the way below the arch apex to create an even wash of light over the masonry form as well as on the water below. The standard fixture was modified to include captive screws and lens tethers because of the over-water installation. In addition, cutoff baffles prevent glare. Another important aspect of the design was the color of the light. 'The pedestrian lighting along the top of the bridge and throughout the pedestrian parkway is white-blue. All of the lighting on historic buildings along the riverfront is very warm, incandescent or high-pressure sodium,' explains Gallina. 'It's appropriate that the color of the lighting distinguishes between the two.' An onsite mockup allowed the designers to carefully check the placement of the luminaires and the color and light intensity of the lamps.

Last October, Mayor Rybak flipped the switch at a public lighting ceremony. Crowds cheered when they saw this important landmark reborn. 'As the lights slowly reached their full brightness, it was really magical,' says Meyer. For Gallina, this project has been one of the 'greatest rewards' of her 16 years of professional lighting design. 'It was a long journey getting everything installed. To see it finally lit was emotionally breathtaking,' she says. Through the support of elected officials, the efforts of a private fundraising campaign, and the sensitivity and attention to detail in the lighting design, citizens are once again able to enjoy this Minneapolis icon.
bette hammel

Bette Hammel is a freelance journalist in Minneapolis.

DETAILS
project Stone Arch Bridge, Minneapolis
completion dates Phase 1: 12 arches over the water, October 2005; Phase 2: 5 arches over land, July 2006
client Friends of the Minneapolis Riverfront, Minneapolis
architect/lighting designer Meyer, Scherer & Rockcastle, Minneapolis
engineer City of Minneapolis Traffic Engineers
photographer Adam Grim
total square footage Phase 1: 33,600 square feet; Phase 2: 22,064 square feet
lighting cost Phase 1: $545,000; Phase 2: $200,000 estimated. (All funding came from private donations.)