Engineering Inc. - May/June 2008 - 28

GrAndAWArds AC E C 2 0 0 8 EnginEEr ing ExC El l EnCE AwArds h U.S. 24 Bridge Rehabilitation Over Rouge River, Dearborn, Mich. Wade Trim—Taylor, Mich. The 1930s-era U.S. Route 24 Bridge over the Lower Rouge River in Dearborn was suffering from extensive cracking and substructure movements which would ordinarily require its replacement. Instead, the project team designed an innovative, alternative approach of installing tensioned steel bars vertically into the original concrete bridge abutments to increase design load. They also installed engineered backfill with biaxial geogrid in horizontal layers to reduce soil pressure against the abutment walls by 75 percent. The project’s innovations saved considerable costs, were completed three months ahead of schedule and avoided significant environmental impairment to the river from construction. h Discovery World at Pier Wisconsin, Milwaukee, Wis. Graef, Anhalt, Schloemer and HGA (Joint Venture)— Milwaukee, Wis. Seemingly floating above water, the 120,000-square-foot Discovery World at Pier Wisconsin science and technology museum is a gleaming showpiece of structural and mechanical engineering. The project team created the museum’s “floating” illusion by designing a unique Z-frame to slip over pipe piles driven into Lake Michigan to assure structural stability. An aquarium built beneath the lake withstands downward forces as well as hydrostatic pressures of 1,040 pounds-per-square-foot. The complex also features interactive exhibit areas, performance and digital theaters, exploration laboratories, and a 250-seat lakefront amphitheater. A rolling lawn extending to the lakefront doubles as the ceiling for the underground parking facility and a “green roof ” stormwater mitigating system. h Spallation Neutron Source Target Hot Cell, Oak Ridge, Tenn. Merrick & Company— Aurora, Colo. The Spallation Neutron Source Target Hot Cell facility generates the world’s most powerful pulsed neutron beams, which are critical in the advancement of material science and molecular research. Neutron research helps scientists improve materials used in a multitude of products such as high-temperature superconductors, powerful magnets, aluminum bridge decks and stronger, lighter plastic. The project team designed the target hot cell—a shielded, confined “operating room” 30 feet high by 14 feet deep and 100 feet long—with walls of 40-inch-thick high-density concrete and a stainless steel liner. It includes a movable intracell shield door and a material transfer system. The structure protects users from intense radiation, and allows confinement and removal of hazardous vapors and radioactive waste. h Tacoma Narrows Suspension Bridge, Tacoma, Wash. Parsons/HNTB (A Joint Venture)— Bellevue, Wash. The new Tacoma Narrows Suspension Bridge—the second suspension bridge built in the United States in the past 40 years—eases enormous traffic tieups, and can withstand an earthquake of 8 on the Richter scale—a must for the region’s high seismic activity. The project team used a ground-breaking cast-in-place dredged caisson foundation system to achieve extreme support requirements—the equivalent of two 20-story buildings underwater— supporting 510-foot-tall concrete towers. The bridge also features 5,400 feet of joint-less superstructure, a 2,800-foot main span housing four lanes, and a pedestrian and bicycle path. The lower level is designed to accommodate additional highway expansion in the future. 28 ENGINEERING INC. MAY / JUNE 2008

Engineering Inc. - May/June 2008

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