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Prairie Architects, Inc. |
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Greenroom Addition |
Economic pressures and the Secretary's Standards force full utilization of the lower level of the Bandshell for performance support functions. However, the area is not handicap accessible, nor is it properly sized to deal with the entire band at once. We have responded to this by designing a new Greenroom Addition attached to the Bandshell. This component has been placed low into the ground -- at the same elevation as the lower level floor of the Bandshell -- allowing the combined existing and new spaces to be used contiguously for costume changing, toilets, and staging areas for performers and support staff. Structure Our studies have suggested that it is imperative to limit the height of this new addition so that did does not protrude over the existing Bandshell parapet wall. Care has been taken to identify a structural system capable of roofing over the Greenroom area, providing sufficient headroom while not exceeding the height of the rear bandshell wall. Ceiling finishes, roof structure, deck, roof insulation, and roof drainage slope all needed to be contained within an overall depth of two feet, the height of the existing Bandshell parapet. Due to these considerations, we have proposed using a two way reinforced concrete waffle slab with the edges turned up to form a 24-inch fascia, thus matching the existing parapet height and blocking the roof insulation from view. This type of construction was developed by the Modernists in response to their attempts to reduce the height of their buildings, simultaneously providing a visually decorative structural system that could be displayed without adornment. It is commonly found in their buildings, and is perhaps one of the most distinctive visual elements in their body of work. The roof structure of the addition will be supported by its own independent structural system consisting of columns and reinforced concrete beams that will be cast integral with the roof structure. The structural columns are pulled away from the Bandshell wall, cantilevering the roof edge to its position next to the Bandshell parapet. The perimeter walls shall be constructed using insulated concrete forms with acrylic stucco exterior finish. The addition has structural independence from the Bandshell, reducing the potential for settlement problems that could arise from the building next to the existing structure. This system has allowed us to incorporate a "transparent" connection that visually obscures the Bandshell only at the facsia. The sidewalls of the Addition are rendered as glass between finish grade and the bottom of the structural fascia, providing a visually open appendage that allows the discerning viewer to perceive the original lines of the Bandshell. Glass serves as the connective tissue to the Bandshell below the roof structure. ADA Considerations ADA access options have been affected by the elevation of the existing roadway to the south, as well as the decision to place the main floor level of the Greenroom at the elevation of the existing sunken Bandshell interior floors. Drainage considerations, as well as space constraints, ruled out exterior or internal ramps. This lead us to the recommendation of interior steps with a mechanical wheel chair hoist to the lower level of the Greenroom and Bandshell. This has been arranged in a bifurcated entry, reducing the need for visitors to walk all the way around the toilets or Bandshell to get inside. We located the circulation at the far end of the building away from the Bandshell in order that the necessarily higher roof structure will not loom over the existing parapet. The waffle slab roof structure has been sloped here to minimize the abrupt elevation changes and to allow for a smooth transition to the optional Public Toilet building adjacent. |
Karl King Bandshell Fort Dodge, Iowa |
Prairie Architects, Inc. -- 103 South Third Street -- Fairfield, Iowa 52556 |