THE TRAIL OF TEARS
The Chickasaw story is based on direction and movement.
Located on a 44 ha site near the Chickasaw National Recreation Area in Sulphur, Oklahoma, the facility is a key contributor to the survival of the Chickasaw nation’s culture. The building recalls the ‘Trail of Tears’ the Chickasaw – indigenous to the south-eastern US but forced in the 1830s to relocate to Oklahoma where most now live. Through architecture, landscape, exhibits and events, the centre embodies guiding concepts of connection, spirit, nature, vibrant culture, rituals, celebrations and continuity. Opened in 2011, it includes national archives, a library and research center, museum, 350-seat performance theater and multiple gathering places for tribal events. The combined building areas cover almost 9000 m2.

Fierce Warriors
The fierce warrior culture of the Chickasaw created a legacy of stories and reputation, but without a written language they were never recorded. “The challenge was to tell a compelling story and build a destination,” say architects Overland Partners. “Those same challenges became the opportunity and basis of inspiration for the center.”
The architecture represents the journey from the woodland forests of the East to the prairies of the West. Building entrances and public spaces are crafted with open volumes and wood structures, while support, circulation, and event spaces are supported by masonry structures with prairie grass roofs. Spaces of significant cultural importance—museum, archives, and theater—are housed in copper volumes that represent traditional Chickasaw vessels.
Exposed wood is used extensively at gathering spaces, such as building entries and lobbies. It also features in the pavilion roofs and the 5-m-wide wood-framed canopy connecting the exhibit and theater buildings.

The architects and structural engineers made extensive studies of wood member types, roof framing options, column sizes and geometries, and member connections. The selected glulam members are Douglas fir, with exposed members specified as AITC architectural appearance grade.

Structural Description
Exposed wood columns, beams, purlins and roof deck feature in the gathering spaces of the exhibit, theatre, retail and research buildings. Similar exposed wood roof framing is used on the exterior structures of the sky, water and bus pavilions. Non-exposed roof framing at each building is framed with structural steel to minimise the number of columns and maximise roof spans. Vegetated roofs are framed with structural concrete to easily address the large applied loads from saturated soil and vegetation.

Overland says connection designs and details posed a significant challenge. “Since the wood connections are exposed, the final configuration needed to be simple and elegant. Too often, wood connections appear ‘clunky’ due to a large quantity of bolts. This issue is especially critical at column bases where connections are readily seen and the resulting loads are highest.
Interior timber cladding

“The architectural concept sought a column base detail with each wood column supported from a single vertical steel plate. After several iterations a base was developed that transferred the code prescribed loads, while also limiting the quantity of connectors between the wood column and the vertical steel plate.
“Given the desired column size, the taller wood columns required moment connections at their bases. The applied base moment yields a force couple that can be resisted via bearing between the wood column face and an adjacent load-bearing surface. Thus, moment connection bases were simply created by adding four steel plates oriented perpendicular to the vertical support plate and aligning the new steel plate with each wood column face.”

Click here to view Overland Chickasaw project page and be sure to read the original article on Timber + Design International’s website here.