...considerable savings. Construction costs were reduced by $15 million and annual debt service dropped to $18.7 million from $25 million. Total debt service decreased by $214.8 million, from $830.9 million to $616.1 million.
Use of Build America Bonds—approved by Congress in 2008—to fund the bulk of the costs saved an additional $77 million by virtue of a 35% federal tax subsidy attached to the bond program. “The final interest rate, a very reasonable 4.5%, is what made the projects feasible,” Mosher says.
Combining the projects offered another significant advantage. Timetables could be overlapped such that construction that otherwise would have taken seven to eight years to complete can be accomplished in four. Unfortunately, that meant closing the museum for one year, but the Historical Society concluded that it might be better to focus solely on the new facility free of the need to operate the museum.
Construction on the HCC is expected to finish in August 2011, but exhibit installation will push the public opening into early 2012. Contractor Hensel Phelps’s timeline puts completion of the cast-in-place-concrete foundation in mid-February with the superstructure, also cast-in-place, topping out by October. Dry-in should happen in early 2011.
“We expect to have 250 workers at peak employment,” says Nathan Lowry, Hensel Phelps project manager. “There’s no lay-down area on site, so we are seeking one nearby. Street closures are not anticipated, although we might occasionally overlap onto traffic lanes.”
Intended to have a 100-year life span, the HCC totals 198,000 sq ft on four floors plus a basement, a substantial increase over the current 140,000 sq ft. The 40,000 sq ft of new exhibit space includes a 10,000-sq-ft gallery for hosting traveling exhibits, an amenity the present museum lacks.
“The HCC combines terrific access, high visibility and sense of permanence with a contemporary but inherently classical look that beckons to the civic and cultural centers, DAM’s Hamilton Building and the neighborhood,” says David Tryba of Denver’s Tryba Architects, the project architect. The design is based on a simple rectangle shaped like Colorado, and it “has a clearly defined base, middle and top,” Tryba says. “It becomes increasingly articulated as it rises skyward.”
A triangular four-story glass curtain wall on the north and a stone tower on the south side “reach out to Broadway as open arms in a welcoming gesture” that helps define the recessed main entry, Tryba says. On 12th Avenue, a dedicated bus lane, “monumental steps,” planters and seating walls will greet touring groups of schoolchildren, he adds.
Echoing the Hamilton Building of the Denver Art Museum is the HCC’s most remarkable architectural feature, a prominent wing-like aluminum roof that will soar above the fourth-floor outdoor terrace. Gallery and event space overlooks the terrace through expansive floor-to-ceiling windows offering stunning views of the Front Range—from Pikes Peak to Indian Peaks.
The exterior is Indiana limestone, chosen for its purity (lack of veining), structural predictability and its ability to endure the roughly 80 freeze-thaw cycles of a typical Denver winter, which are especially hard on building stone.
Chief among the drawbacks of Colorado stone was the need to ship it east for cutting and milling, a fact that made its Indiana counterpart far more cost effective.
But Colorado stone will also be amply represented. “Significant amounts of native Colorado Yule, sandstones and limestones will enrich the interior,” Tryba says. “Stone elements anchor the building to geology and the Earth and reflect the past, while the ample applications of aluminum and glass look to the future.”
The museum will seek LEED-Gold certification. Daylighting will permeate most of the building via a central atrium capped with a serrated-glass skylight, prominent glass curtain walls and horizontal bands of windows. Only gallery spaces intended for light-sensitive artifacts will employ artificial lighting.
LED ceiling lights illuminate public spaces. Curtain walls are double-pane, Low-E fritted glass embedded with fine ceramic particles that deflect heat.
Other key sustainable features include the building envelope—double masonry walls, water and vapor barriers and a reflective white PVC roof — a high-performance electrical and mechanical plant, waste-heat recovery system, advanced ventilation, occupancy sensors and controls, sensored faucets, waterless urinals, locally sourced concrete and recycled steel, and rooftop photovoltaic panels.
“The auditorium and gathering spaces accommodate groups up to 800 and meal service for 400,” says Ed Nichols, Colorado Historical Society president. “Street-level retail includes a restaurant and the museum store. Collections will be more open and visible. Besides contributing to daylighting, the atrium offers ‘Colorado Voices,’ an exhibit devoted to prominent historical figures who have helped shape the state. Meanwhile, we have launched a $33-million campaign to fund new exhibits.”