[Construction Equipment]
May 5, 1998

EMP challenge: turning sculpture into a building

Journal staff reporter

To look at it is to wonder whether it's even possible to construct. World-renowned architect Frank Gehry's abstract design for the Experience Music Project is a wonder of physics and engineering. Putting it all together is often like space travel.

For the contractors and engineers charged with the task of building this structure, every step of the process requires the ability to innovate. From the unusual materials used to construct the giant sculpture to the spaghetti-shaped support beams that will make up its skeleton, Paul Allen's $60 million museum of rock 'n roll is a one-of-kind undertaking.

EMP project shot

Having the monorail run through the EMP is just one of many interesting puzzles design and construction crews have had to solve.
Photo by Sky-Pix

In May, EMP's general contractor, Hoffman Construction, will begin assembling the twisted web of steel that will support the 130,000-square-foot structure. But a look at the site even today hints at just how non-geometrical the finished building will be. The site, in the shadow of the Space Needle, shows massive excavation craters and the tangled "rat cage," the welded rebar that will support the foundation.

"There isn't a right angle anywhere on the exterior," said EMP's Construction Project Manager Paul Zumwalt, using his hand to trace lines in the air where the steel blob will someday rise.

"The unusual shapes are the biggest challenge," Zumwalt said. "The strength and integrity is there. It's a matter of making it all fit together."

The building was inspired by the sexy curves and colors of electric guitars. On the surface, it looks like a monolithic abstract sculpture that fits comfortably amid the Buck Rogers landscape of Seattle Center's Space Needle and the roller coaster Windstorm.

But if the building were just a sculpture, constructing it would be easy. The challenge is to make this work of art a functional building to be visited by millions for years to come.

Paul Zumwalt

Paul Zumwalt

When EMP sought proposals from subcontractors to help build the museum, a few firms shriveled at the challenge of making the seemingly impossible possible. Not only was the shape of the building a daunting factor to some, Zumwalt said, but accommodating a monorail track that would run directly through the building and doing so with few track closures made the job a bit too uncertain for some companies.

"We, like almost every project in this market, are having trouble finding the trades and workers to get everything done," he said. "Some of the contractors have run away from this project because of its complexity."

Despite the difficulty of finding contractors and the inflated prices of a hot construction market, EMP has held to its budget and its schedule, Zumwalt said. It has been a year since the project first broke ground, and the difficult engineering and design work is mostly complete.

Now Zumwalt's team is tweaking the plans, making minute adjustments to beams around the footing of the monorail track and ensuring there's ample clearance for the monorail trains that will pass through EMP.

The monorail still rides on the same piers that have supported it for 35 years, but over 75 percent of the soil supporting two of the piers had to be removed during the excavation phase. To ensure the foundation walls can withstand the pressure of the decelerating trains, the EMP staff plotted the slight differences in the path the monorail takes as it rounds the curve on different trips. By using global positioning sensors on the train, they determined the widest path of the monorail.

Inside the building's 65-foot-high Sky Church room, large exposed beams will wave like ribs across the ceiling, making visitors feel like they've been swallowed by an enormous whale. It is in this room where the challenge that faced the Seattle engineering firm of Skilling Ward Magnusson Barkshire will become most apparent.

According to Skilling's principal in charge, Jon Magnusson, the biggest question that faced the engineers was deciding which support system would best suit the unusual demands of Gehry's design. They considered a folded space frame structure, a concrete shell and precast concrete rib beams. But, in the end, they decided the most pliable yet structurally durable alternative would be a series of steel-plated girder ribs.

"It was a reflection of how you might build a boat or an airplane with ribs," Magnusson said. "It's even like the ribs of a human body or a whale."

EMP site model

The EMP's abstract shapes are at home with the Space Needle and Windstom roller coaster at Seattle Center.
Photo courtesy of EMP.

In fact, the ribs made for EMP are actually closer by design to organic ribs, because each one is unique in its curvature and size. Columbia Wire & Iron of Portland is in the process of sculpting more than 50 beams which will weigh 5,000 to 10,000 pounds each. To do the job the company had to customize a steel press bed that uses rollers to shape each rib's web and flange pieces identically.

Director of Engineering Brian McIntyre and Project Manager Carolyn Bird, both of Skilling, spent months trying to make sense of the inherently crooked structure. The most difficult aspect of the task was visualizing a three-dimensional object ruled by chaos, Bird said.

"Sometimes the geometry is not apparent on paper," she said. "You have to to be able to walk into the building. In this building if you see a straight line its profile probably isn't straight."

Fortunately the design team has at its disposal a state-of-the-art computer program called CATIA. This next-generation computer-aided design tool is used by Boeing to construct airplanes. Skilling found its ability to map three-dimensional space and structures was perfect for solving the physical conundrums posed by EMP. Still, Bird said, it was difficult to mentally translate the design from computerized image to paper to reality.

The same problem vexed Hoffman's Project Manager Chris Raftery. Like everyone else involved in the project, Raftery had never worked on a design so abstract and devoid of straight lines. Every step of the construction phase has been a learning process, he said.

"The biggest difficulty is figuring out how to build a one-of-a-kind structure," Raftery said. "It's like learning how to build a car on a custom basis. Getting people to understand how the building fits together is a challenge."

Just about every aspect of the building poses a different riddle. Huge ameboid windows will require custom fitting and unusual support mechanisms. Placement of the ribs will be a tedious task, because Raftery's team will have to use electronic equipment to determine the balance point of each piece of steel. Temporary braces will have to be customized to support the structure while it's being built.

Another problem is the density of the work site. The footprint of the 135,000-square-foot building stretches to the edges of the lot in almost every direction. To get a sense of where each part of the building will be in this tight area, Hoffman is using a geometer electronic surveying device. Usually used for road construction, this measuring device allows Hoffman's crew to reference any point in space from any other fixed point.

EMP model

Once the steelwork is erected, crews from Hoffman Construction will pour concrete over the skeleton and EMP's rippling forms will take shape.
Photo by Joshua White, courtesy of Frank O. Gehry and Associates

Once Hoffman erects the steelwork, workers will begin pouring concrete over the skeleton, and its unique shapes, rippling folds and crevices, will begin to take shape. After that, crews will lay insulation between the concrete subdermal layer and a second skin made mostly of colored stainless steel.

The second-skin material is much like what is used to cover the hull of airplanes. It was the thickest steel available that was still able to bend to the ever-changing plane of the building's surface.

The building will be divided into four different colors of stainless steel skin -- blue, reflective metallic purple and a gold and purple interference color that changes hues like a mood ring depending on where you stand.

Right now, Hoffman has 65 construction workers at the site. That number is expected to hit 80 in two weeks when the steel begins to rise. A year from now when the building finally takes shape, the company will employ some 250 workers on site.

Nearly every aspect of this project seems to involve some level of innovation. Bird said the technology used to build EMP will not only allow other projects like it to be built in the future, but it will also enhance the way typical buildings are constructed.

"(EMP) has gone steps beyond what a typical, conventional building would look like," she said. "We've shown it can be done. It will help build more conventional building more efficiently."

So far, the EMP building is progressing with only minor snags. Despite the fact that no one involved in this project has ever constructed a building like EMP, everyone has little doubt that the structure will function as it was designed. For the men and women who are making the seemingly unimaginable a reality, each day continues to test their ability to innovate.

"It was totally foreign to me," said Magnusson. "It was a totally different place than we'd ever been before."

Copyright © 1998 Seattle Daily Journal of Commerce.