ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.
Issue link: http://www.aspiremagazinebyengineers.com/i/657823
PA R T N E R S P O T L I G H T 30 | ASPIRE Spring 2016 Bridge owners share common interests and responsibilities to achieve multi- modal transportation results that have the longest service life, lowest maintenance costs, are built quickly and efficiently, incorporate sustainable solutions, and are appreciated by the local and regional communities they serve. In creating sustainable solutions, the best value comes from a combination of economic efficiency, environmental sensitivity, and social involvement. When all of these factors come together, combining functionality, sculptural form, and a focus of over a 150-year service life, the bridge result is inspiring. Economical Bridge Solutions In the late 1970s and for a number of years beyond, alternate bridge design types were competitively bid against each other in construction whenever federal funds were over $10 million dollars. Often, concrete segmental bridges were bid against other concrete and steel bridge types simply based on low cost as the selection factor. Concrete segmental bridges proved themselves in the marketplace with lower costs derived from repetition and speed of construction. Using local materials and local labor, longer spans, fewer and more slender singular pier shapes, and construction methods that reduced activities in environmentally sensitive or traffic-packed sites made a difference to economical, efficient bridge solutions. These bridges were also recognized for pleasing aesthetics, which was simply a natural outcome of the overall design. The concrete segmental bridge industry grew throughout the United States building on the outstanding results in constructability and value. One example is given on the next page showing the photograph of the Insterstate 93 (I-93) bridges in Boston and the description of cost savings. Sustainable Success One of the triple bottom line areas for sustainable success is economy. In addition to initial cost, reduced maintenance budgets for many owners mean best value solutions now take into account lower maintenance costs for saving money in the future. Also, environmental sensitivity and social involvement are other key areas evaluated in determining factors for resilience in our growing communities. Technology in concrete materials, equipment, and cable-stay systems have aided in advancing concrete segmental bridges with new opportunities to reduce site footprints with longer spans. Examples include the new Harbor Bridge in Corpus Christi, Texas, with a 1655 ft concrete segmental cable-stay main span, and the new I-35W Bridge in Minnesota with a 504-ft concrete box girder main span. Precast concrete segmental construction methods provide superstructure assembly from the deck level without using cranes on the ground. A good example is the Selmon Expressway in Florida shown on the next page. This allows traffic to remain in operation throughout construction while building in limited right of way. In Selmon's case, the bridge doubles vehicular capacity while only using a 6-ft-wide column in the medium of the existing 4-lane highway. The 9-mile AirTrain JFK in New York carries rail on a precast concrete segmental bridge down the middle of the busy Van Wyck Expressway. Over 160,000 vehicles a day were maintained during construction. Social success means that the bridge respects the community it serves. Concrete Segmental Bridges Photographs of concrete segmental bridges throughout the United States that represent solutions for sites with environmental sensitivity, tight urban right of way, long spans of water, crossing over active highways, and serving multi-modal transportation. Best value benefits have been recognized with over 350 awards for bridge owners. by Linda Figg, FIGG The Best Value Solution for Economy, Sustainability, and Beauty COLORADO MAINE UTAH OHIO NEW YORK