“The Lewis & Clark Confluence Tower will not only be a superb tribute to two of our nation's most adventurous explorers, but it will support the local economy by bringing countless new guests to the region that will support local businesses.” The Lewis & Clark Tower project consists of a 180-foot concrete tower, high enough to view the confluence of the Mississippi and Missouri rivers to the west and the new interpretive center overlooking a replica of Camp DuBois.
The tower is equipped with both an elevator and staircase to allow visitors to reach the panoramic view. Located on 60 acres, the project will include fountains, a gift shop with restroom facilities, and picnic areas with direct access to the new Confluence Bike trail. With funding coming in spurts, Moore's group planned the project in three phases—the initial construction, the interior upgrade, and then the final grading that included the construction of a precast building.
Unfortunately for the city leaders, moving the project forward took a little longer than they had hoped. In fact, Lyle Bowman, the project coordinator for High Concrete, the concrete producer that cast the elements, it was one of the toughest projects in his more than 15 years in the concrete industry.
Organizers originally planned to open the observation tower in spring 2004 to tie into the opening ceremonies for the start of the Bicentennial celebration of the Lewis & Clark expedition.
Originally, the designer had planned for the tower to have a cast-in-place core, and to use architectural cladding to create the fins. Eventually, through consultation with Dennis Nemez, High Concrete's regional sales manager, the designer agreed to the precast approach.Tall and wider at the top
For Bowman, the most intriguing view of the structure is to stand at the tower's base and look straight up. One unique feature of this project is that the tower actually widens as it rises. “The architect wanted to provide a sense of openness for those that climbed to the top,” says Bowman.
The design presented a significant problem to Bowman's team that delayed the start of the project. The team wanted to check the design to determine how the thin, tall structure would react under a wind load. “We had to convince the owner that we needed a wind tunnel study,” says Bowman.
The elements were cast by High Concrete's plant in Springboro, Ohio, and trucked to Hartford. The project was cast with self-consolidating concrete, which helped achieve the desired fluted look on the tower's sides.
The structure's exterior also posed some challenges for the design team. Originally, the architect wanted the cast-in-place structure to be cladded in precast panels. But when the project turned to precast, there were no panels. The distinctive coloring was stained onto the concrete surface at the plant.
To learn more about the Confluence Tower memorializing the winter camp and beginning point of the Lewis & Clark Expedition, visitwww.confluencetower.com.