Mid-Continent Tower Wins 25 Year Award
Designed by Dewberry, Iconic Tower Defines Tulsa’s Skyline
The Mid-Continent Tower, a landmark 36-story office building in downtown Tulsa, Oklahoma, has been recognized with the prestigious 25 Year Award from the Eastern Oklahoma Chapter of the American Institute of Architects (AIA). The award was presented to the Tulsa office of Dewberry (then known as HTB), which designed the distinctive tower for then-owner Reading & Bates in the early 1980s.
Among the most challenging design and construction projects in the nation at the time, the Mid-Continent Tower was built adjacent to and above the historic 16-story Mid-Continent Building, also known as the Cosden Building, which is listed on the National Register of Historic Places. Reading & Bates, an energy resources company, owned the circa-1918 building and sought to expand the property to serve as its headquarters.
Because the existing building’s structural system would not support additional weight, Dewberry’s design concept called for constructing the tower’s base adjacent to the building to its full height, and then cantilevering over the building for an additional 20 stories. In all, 330,000 square feet were added to the original 90,000-square-foot building, aided by a series of five massive steel trusses, each weighing 230 tons.
In order to replicate the original building’s terra cotta façade, the Dewberry team researched available manufacturers to create the 85,000 tiles, spires, cornices, and moldings required for construction. With the peak of Tudor Gothic-revival architecture long past, only one American firm still manufactured terra cotta tiles at the time, a company called Gladding, McBean & Co. in Lincoln, California. The company, which had never manufactured such a large order, expanded its operations to meet the requirements, which included more than 7,000 different shapes and 13,000 hand-made tiles.
“This was a unique project in my career,” says Vic Thompson, who designed the project and has been with the Tulsa office of Dewberry for 42 years. “There has never been another like it, before or since.”
Thompson notes that research for the design of the tower took him to Carrara, Italy, twice to select the marble. A trip to Quebec’s Chateau Frontenac aided in the research for the building’s copper roof. He also visited New York City, where he toured the landmark Woolworth Building; and California, where the terra cotta manufacturer was located.
“We went to great lengths to complement the historic building and not diminish it in any way,” says Thompson. “The tower is a tribute to the existing building, and there is a lot of Tulsa history in the stories of both of those buildings. I see the tower as I drive to and from work each day, and I think of Charlie Thornton, who was president of Reading & Bates. It was his commitment, and his vision to create this building for the city. I realize that there is a whole generation of Tulsans who don’t know the story behind the tower, or that it is actually two buildings constructed more than 60 years apart. It was an amazing effort.”
“Dewberry’s design and attention to historic details in the Mid-Continent Tower was a phenomenally innovative architectural and engineering solution,” says W.Lowell Heck, vice president of corporate operations with Flintco, LLC, the general contractor for the project. “The cantilever design for this high-rise expansion preserved the visual impact of the original historic structure. The construction of this landmark building truly stands out as one of the most challenging and rewarding projects in Flintco’s 104-year history.”
The building won numerous awards upon its completion in 1984, including a National Trust Preservation Honor Award.
- The steps to create the 85,000 terra cotta tiles, which included a ten-day firing process in a 325-foot-long kiln, was largely unchanged from when Gladding, McBean & Co. was formed in 1884.
- Flintco streamlined the cladding process by creating an offsite method for attaching the terra cotta into large, steel-framed panels, which were then lifted into place similar to precast panels. This technique saved several months in the construction schedule.
- The building’s terra cotta façade and copper roof echo the design of New York’s Woolworth Building. The roof’s green patina was achieved with a treatment of a nitrate solution.
- The five parallel steel trusses, each two stories high, cantilever 40 feet over the historic building. The building owner, Reading & Bates, readily understood the proposed solution as a result of its own work with offshore oil rigs, which are often constructed using the technique. The building’s entire frame weighs 6,200 tons. The cantilevering process was documented in the May 19, 1983, issue of Engineering News-Record: “In this building, 20 stories cantilever 40 feet from a slender base. And the building is clad in terra cotta, whose weight accentuated the difficult…By refusing to be deterred by all of this, the Oklahomans have given Tulsa a beautiful building. They’ve given the rest of us an example of the satisfying things that can be produced when you’re not afraid of the unusual.”
- The marble panels in the tower were carefully selected to match existing interior walls in the original building. Three types of Italian marble were selected, and two from Tennessee.
- The original Mid-Continent Building, built by Tulsa oil baron Josh Cosden as the headquarters for the Cosden Oil & Gas Co., was at one time considered the largest reinforced concrete structure west of the Mississippi.
- When Dewberry began designing the tower, the firm had just completed the restoration of the historic building. The process revealed many original details that had been hidden by numerous remodelings. Many of the building’s features, such as ornamental plaster rosettes, were replicated in the new tower.
- The tower's lobby features a panoramic view of the Tulsa skyline composed of 20 panels of locally made stained glass, as well as four paintings reflecting the old West. A two-story “colonnade” entrance is formed by four terra cotta arches.
- The tower features a sloped floor auditorium at the 15th floor with a racquetball court beneath. On the 36th floor, a stained glass dome forms a ceiling over the three-story spiral staircase that connects the top floors. A terrace on the 36th floor offers panoramic views of Tulsa.
Photos by Jon Petersen
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