Christine H. O'Toole

PNC is fine-tuning the features of its almost-complete, ultra-green tower in Pittsburgh with a full-scale mock-up. The Tower at PNC Plaza, designed by Gensler, is nearing completion in Pittsburgh. The 33-story building is expected to rely on natural ventilation for more than 40 percent of working hours and use only half of the energy of a standard office building. A squat 1,200-square foot outdoor mock-up erected in a Pittsburgh industrial park is helping PNC Financial Services Group refine The Tower at PNC Plaza, which the company claims will be the world’s greenest skyscraper. Scheduled to open this fall in downtown

The former Steel Town embraces its rivers and green design Image © Jason Varney Pittsburgh's identity has always been its work. Thirty years ago, when it lost the steel mills that had forged its 20th-century reputation, it became part of the Rust Belt, with a fractured economy and three polluted rivers: the Ohio, Monongahela, and Allegheny. View Larger image Map by Norman Hathaway RELATED LINKS: Tower at PNC Plaza Center for Sustainable Landscapes Today, locals use the rivers for play as well as work. On sunny summer weekends, the water buzzes with kayaks and pleasure boats, thousands flock to outdoor

Photo © Brad Temkin The angled zinc-clad walls of Carnegie Mellon University’s Gates Center for Computer Science and Hillman Center for Future-Generation Technologies were completed in 2009 and rise from a ravine on the western side of the urban campus. The LEED Gold–certified complex, designed by Mack Scogin Merrill Elam Architects, is made up of a six-story structure and a smaller, trapezoidal, four-story one, connected by a glass-enclosed lobby with pedestrian bridges. Michael Van Valkenburgh designed a naturalistic landscape for the buildings that features five green roofs and a winter garden. CMU’s School of Architecture has been an influential advocate

Image courtesy Andropogon/Riverlife The steep banks and industrial history of the Allegheny River pose challenges to ecological restoration. Railroad tracks, the site of an 1877 strike, run along the river to the Strip District, a landmark marketplace on the river’s southern shore. An early plan by Andropogon for the Allegheny Riverfront Green Boulevard proposes strategies for stabilizing the failing riverbank and slowing stormwater runoff. The scheme calls for a continuous 95-foot setback for public use. A proposal by the Buncher Company for a mixed-use development on a 55-acre site that is part of the area covered by the boulevard plan