After Glow

April 18, 2005

The Kansas City, Mo., skyline—and future—is looking much brighter these days. With the flip of a switch, three Missouri River bridges recently were transformed into an elegant, glowing gateway to downtown Kansas City. Dressed up with more than 180 new decorative lights, the parallel structures now shine as a symbol of the community’s unity, connectivity and vibrant future.

The Kansas City, Mo., skyline—and future—is looking much brighter these days. With the flip of a switch, three Missouri River bridges recently were transformed into an elegant, glowing gateway to downtown Kansas City. Dressed up with more than 180 new decorative lights, the parallel structures now shine as a symbol of the community’s unity, connectivity and vibrant future.

“The lights give people an opportunity to see the city in a new way,” said Bill Dietrich, president and CEO of the Downtown Council (DTC), the group responsible for spearheading the enhancement project. “The bridges make some very grand, cordial gateways into downtown. From the airport, they’re the first impression people have of Kansas City, so they provide an excellent opportunity for Kansas City to make a bold statement about itself.

“Most importantly, the bridges symbolically reinforce areas north and south of the Missouri River as one community.”

The bright idea took shape during the city’s sesquicentennial celebration in 2000 when a group of civic leaders created the “10 Giant Steps for Kansas City,” a long-range community development and beautification initiative for revitalizing the area. The visibility and prominence of the bridges—carrying more than 180,000 cars back and forth across the Missouri River each day—made the beautification program one of the first steps to be implemented.

“Highway infrastructure is a vital part of any community,” said Linda Clark, assistant district engineer for the Missouri Department of Transportation. “It must complement the surrounding development in operation, maintenance and aesthetics. The lights on the Missouri River bridges enhance the structures in a way that complements the development downtown.”

Kansas City-based HNTB Corp., the firm that designed each of the bridges decades ago, was asked to coordinate the $3.2 million public-private partnership project. The overall plan called for unifying the bridges into one gateway, while maintaining and complementing each bridge’s unique personality.

A dramatic statement

The project’s dramatic unveiling was held on July 2, 2004, in conjunction with “Heart of America: A Journey Fourth,” the region’s bicentennial commemoration of Meriwether Lewis and William Clark’s journey to the area in 1804. The legendary expedition marked the official arrival into what is today the Heart of America.

During the lighting ceremony, leaders offered a different kind of history lesson. Just minutes after the lights were turned on, they were briefly turned off again—a reminder of what the city looked like before the enhancements were made.

“The response we’ve received from people has been great,” Clark said. “People who hardly noticed the bridges before are now excited about the way they look.”

The right light

Dozens of factors must be considered when lighting a bridge, or in this case three bridges. Which structural elements should become the focal points? What type of lights will best highlight those elements? What color should the lights be? How and where will the lights be mounted, and can they be efficiently maintained? What is the best way to demonstrate concepts to stakeholders?

Once the opportunities for highlighting the unique character of each bridge were identified, HNTB employed a combination of state-of-the-art technology and old-school methods for testing the initial lighting plans. While the majority of the plans were developed using lighting software and 3-D imaging programs, such as AGI 32 and 3D Studio Max, some rather unconventional experiments also were necessary.

“Even with today’s technology, nothing quite compares to seeing the real thing,” said John Schallert of HNTB, lead electrical engineer for the project. On the Broadway Bridge, for example, the team needed to test a red filter to make sure the light would reach the highest points of the tied-arch bridge. To do the test, they built a wooden test apparatus mounted with a 750-watt light, a portable generator and sandbags. They then perched it out onto the structure and, using stationary cameras, photographed the light beam shining up from the apparatus at 15 different points on the bridge.

Back at the office, the team used PhotoShop to splice the photographs together and create a master image depicting what the lighting scheme would look in its entirety.

“This was as close as we could get to the real thing during the conceptual stages,” stated Schallert.

And in the “Show-Me State,” where seeing is believing, the images proved instrumental in garnering public and private support.

Of course sophisticated computer programs, such as 3D Studio Max and AGI 32 (a program that uses photometric data to calculate exactly which type and brand of fixtures will create the desired outcome), also were used to create 3-D bridge models and original illustrations of the lighting concepts.

Function first

Each bridge lighting design was approached with ease of maintenance in mind. On the Broadway Bridge, for example, HNTB’s structural engineers designed custom brackets that allow the fixtures to be accessed directly from the bridge deck. The brackets, which attach to the underside of the tied-arch bridge, are counterweighted and hinged so one person can easily access the lights for maintenance.

Also a consideration was how the glare from the lights might interfere with navigation on the waterway below. To make sure the boat pilots’ vision would not be impaired at night, HNTB installed instant, electronic photocells and delayed timers in front of large retroreflective panels on each bridge. If necessary, pilots can shine a spotlight up onto the photocell to turn the lights off for up to 15 minutes at a time.

Because the design also needed to be flexible enough to feature a variety of color schemes during community celebrations (such as red, white and blue for the Fourth of July), lights with an interchangeable color filter system were used. On the Paseo Bridge, fixtures with integrated light-changing capabilities were specified and installed so the colors of its four booming 7,000-watt searchlights could be programmed to change colors automatically. This programming now occurs from a control panel on the bridge and will eventually be accessible via telephone.

Making it last

“Surprisingly, the massive bulbs have pretty lengthy life spans,” Schallert said. “It follows a statistical curve, but the median life is more than five years.” The high-pressure sodium lamps, for example, can burn for more than 20,000 hours. A photocell enables the lights to turn on automatically at dusk, and a clock is programmed to turn them off during the night to reduce the number of hours of illumination. The length of time the lights are on depends upon the time of year but typically averages 6.5 hours a night, which means that most of the bulbs can last for several years.

An endowment also has been established through the fund-raising efforts in order to maintain the lights and pay for electricity, which is expected to average about $50,000 a year.

Next steps

Although the stage has been set, there still is more work to be done. While the community is basking in the glow of the newly illuminated bridges, the DTC and HNTB are working behind the scenes to make the gateway even brighter.

In addition to installing new gateway monuments at the north and south ends of the Broadway corridor during 2004-2005, the team also is considering additional bridge lighting enhancements for two railroad bridges along the Missouri River corridor.

“There’s a great feeling of pride that comes from lighting the bridges your firm designed decades ago,” Schallert said. “It makes you wonder what’s next—what the next generation of bridge enhancements will be.”

About The Author: Cline was the lead designer and project manager for Kansas City’s bridge-lighting project. He serves as design director in the Urban Design + Planning group at HNTB Corp. in Kansas City, Mo.