The Ark Encounter attraction, in northern Kentucky, is one of the largest timber-framed structures in the world.
Courtesy Troyer Group The Ark Encounter attraction, in northern Kentucky, is one of the largest timber-framed structures in the world.

The term “of biblical proportions” is rarely meant literally, but a new museum in Williamstown, Ky., may be an exception. Completed in July 2016, the Ark Encounter purports to be a full-scale replica of the titanic wooden vessel built “300 cubits long, 50 cubits wide, and 30 cubits tall” by the prophet Noah to preserve life during an apocalyptic flood, according to the Book of Genesis. A Hebrew cubit—which biblical scholars say was based on the length of a person’s forearm, from elbow to fingertips—is estimated at 20.4 inches, making the ark replica an astounding 510 feet long, 85 feet wide, and 51 feet tall.

Owned and operated by the Petersburg, Ky.–based Christian organization Answers in Genesis (AIG), the $102 million, 120,000-square-foot attraction aims to interpret the biblical narrative of the flood literally, a story that appears in Judaic and Islamic traditions in addition to Christianity. Built almost entirely of wood, the museum is reportedly the largest timber-framed structure in the world—but it is not the first ark replica. In 2013, Dutch carpenter Johan Huibers completed a 410-foot-long ark in the Netherlands. His model, however, has a steel core and a wood façade—a route AIG initially planned to pursue until LeRoy Troyer, FAIA, joined the conversation.

The founder and president of the Troyer Group, in Mishawaka, Ind., has designed several large-scale timber structures throughout his career, including amusement park attractions and the American Countryside Farmers Market, in Elkhart, Ind. Growing up Amish, a Christian sect renowned for its old-world craftsmanship, Troyer spent his childhood on a farm outside Middlebury, Ind., helping erect barns and other wood structures.

Still, turning to the Bible for building specs was a first for Troyer. Besides the ark’s dimensions, “there’s very little instruction in Genesis,” he says. Troyer envisioned the structure to be a hybrid that would employ traditional methods of shipbuilding and woodworking alongside cutting-edge technology and CNC machines. He worked with Tim Lovett, an ark researcher and exhibit designer for AIG who had developed computer models of the ark to understand how it might have been constructed.

Visitors to the museum make their way up a 450-foot-long ramp, entering near the ark's stern. A 45-foot-tall main exhibit hall, or “hold,” is divided into three levels, which are accessed via interior ramps that wrap around a 65-foot-tall central atrium that delivers natural light from the roof deck to the lowest level. More than 130 exhibits, including wood-carved animals, ancient Bible manuscripts, and full-scale dioramas of what scholars believe life was like on the ark, line the museum perimeter.

Visitors enter the 510-foot-long attraction via a 450-foot-long ramp near the ark's stern.
Courtesy Troyer Group Visitors enter the 510-foot-long attraction via a 450-foot-long ramp near the ark's stern.
Longitudinal building section
Longitudinal building section

Sitting above grade on 100 15-foot-tall concrete piers, the structure consists of a series of timber bents, or cross frames, spaced every 18 feet. Each timber bent spans the 85-foot width of the boat and stands 50 feet tall, and comprises two Engelmann spruce logs, each nearly 4 feet in diameter; two 20-inch-square Douglas fir posts; and two 18-inch-deep glulam ribs, which form the ark’s gently curved hull. Knife plates as long as 11 feet help tie the center logs in 16-inch-deep joists, all of which are tied together by equally large crossbeams and diagonal bracing. Infill joists and glulam ribs occur every 6 feet. The resulting dense grid of exposed timbers “is almost a wire frame structure with wood,” Troyer says.

But the project component requiring the most amount of research, Troyer says, was the exterior wood finish. Seeking a material that would last upwards of 150 years, he selected Accoya, a weather- and pest-resistant wood product by London-based Accsys Group. The wood for the ark was harvested in New Zealand, then shipped to the Netherlands for the acetylation process, which uses a highly concentrated form of vinegar to alter the chemical makeup of the wood and render it extremely durable. The Accoya planks, left unfinished, will weather to gray over time.

Building section with call out to wall detail
Building section with call out to wall detail

Generally speaking, sourcing wood for the project was a challenge, Troyer says. The massive Engelmann spruce logs near the center of the structure, for instance, were originally meant to be yellow pine, but when the logs arrived for milling at Colorado Timberframe, in Lafayette, Colo., they didn’t meet the structural requirements. Such large members are hard to locate, but Troyer was able to acquire the Engelmann spruce logs from a dead stand in Utah, which had the added benefit of being already dried. The longest spruce logs, however, were 17 feet short of the 65 feet required. The team made up the difference by splicing logs together, but the seam required additional support.

The diameter of the spruce logs also created an issue for manufacturer Colorado Timberframe, whose CNC machines—despite being among the largest available in the U.S.—could only accommodate up to 24-inch-diameter logs. Consequently, the workers had to build an improvised jig with wood rails and a custom yoke. Measuring from the centerline, they then chiseled and drilled the notches by hand. Six workers could notch one log over two days.

Nearly 90 flatbed trailers transported the timber to Kentucky. Once the wood was on site, erecting the ark was relatively straightforward, thanks both to Bentley Systems' AECOsim BIM software used by the architects and to a sophisticated labeling system employed by Colorado Timberframe. Troyer says the construction efficiency was due in large part to the crew of approximately 100 Amish laborers, hailing from seven different states, who erected the ark in 54 weeks. The giant timber bents, for example, were assembled in two pieces flat on grade following a template painted by the workers onto the ground. Multiple cranes then hoisted them into place.

All told, Troyer estimates that the project, which required nearly 5,000 pages of construction drawings, contains 3.3 million board feet of wood and 190,000 pounds of custom steel plates for its 4,000-plus structural connections.

From a technical standpoint, of course, the ark is still more a building than a boat. Besides being up on concrete piers, it wouldn’t fare any better in a flood than a typical museum building. But it will withstand wind. Thanks to three five-story concrete masonry towers situated behind the ark that provide shear resistance, the ark is designed for wind loads roughly 15 percent greater than the building code–minimum load of 100 miles per hour. “We wanted to make sure that if we have thousands of people in the ark at one time, and there’s a big storm, we’ve made them as safe as possible,” Troyer says.

The replica structure comprises a series of timber cross frames, spaced 18 feet on center, that include two 18-inch-deep glulam ribs, which form the building's curved hull.
Courtesy Troyer Group The replica structure comprises a series of timber cross frames, spaced 18 feet on center, that include two 18-inch-deep glulam ribs, which form the building's curved hull.
Harvested from a dead stand in Utah, the Engelmann spruce logs hand to be hand-notched due to their large diameters.
Courtesy Troyer Group Harvested from a dead stand in Utah, the Engelmann spruce logs hand to be hand-notched due to their large diameters.