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/306966
The Fifth Street Pedestrian Plaza Bridge in Atlanta provided a pedestrian-friendly environment. Photo: ARCADIS U.S. Inc. The Daggett Road Bridge environmental constraints played a key role in determining the type of bridge. Photo: DMJM Harris. 16 | ASPIRE , Winter 2008 P E R S P E C T I V E Concrete is the number one building material in the world and ranks second only to water as the most consumed substance of our time. As bridge engineers, we use concrete in every bridge project from foundations and piers to abutments, superstructures, bridge decks, and barriers. Our cultural and professional responsibility has been to design safe, economical, and constructible systems that meet the current and relatively short-term future needs of the owner and the public. While we must continue to accomplish these goals, we must also consider the impact of our choices on future generations. Almost everyone has heard about sustainability, usually in an environmental context. As the awareness of sustaina- bility grows, we should question whether concrete bridges can really make an impact on the sustainability movement. The intuitive answer is "absolutely; concrete structures can and do have a positive impact." This issue of ASPIRE™ and the next three issues focus on concepts of sustainability as they relate to concrete bridge systems. Concepts of Sustainability S u s t a i n a b i l i t y h a s r e c e i v e d v a s t awareness recently, specifically related to the impact that humans have on the earth's resources and environment. This attention is being focused on every aspect of our built environment; the homes we live in, the buildings we work in, the cars we drive, and the roads we drive on. Is sustainability just the next buzzword or fad? Considering how many aspects of our lives are affected, most authorities believe sustainability will become a driving force that permeates all facets of our lives. The commonly accepted definition of sustainability, as used by the United N a t i o n 's W o r l d C o m m i s s i o n o n Environment and Development in their 1987 report titled Our Common Future, states "Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs." To the concrete bridge community, this definition means designing, constructing, and maintaining context-sensitive bridges with long-term durability, low life-cycle impacts, sensitivity in the selection of materials and methods, and a minimal impact on the environment throughout the bridge's life. A s u s t a i n a b l e d e s i g n i n v o l v e s consideration of its impact on society, environment, and economy. A balance must exist between these three elements to provide the best solution. Sustainable designs reduce the amount of waste material, minimize the social impact of construction congestion, and cost less per year of service over the life cycle of the structure. The choices that we make not only affect the construction costs or environmental impact of a project, but clearly affect the public perception of our engineering solutions. Assessing the carbon footprint of an individual, process, industry, or country is one way to assess and quantify sustainability. However, this tends to focus only on one aspect—the environment—while diminishing the social and economic tenants of sustainability. Now, more than ever, we need innovative solutions that respond to our economic and social well-being. Moving Forward from Common Practice The bridge engineering community has been practicing many sustainable concepts for decades. Rapid construction, contractor alternate designs, value engineering, lean manufacturing, and extending service life through reliable and durable systems all contribute to sustainable practices. Rapid construction concepts incorporate a get in, get out, and stay out philosophy, while demonstrating improved quality through rigorous quality control and assurance. These concepts limit the adverse affects of detours and traffic congestion on commuters and local businesses. Contractor alternate designs by Dr. Tess Ahlborn SUSTAINABILITY For the Concrete Bridge Engineering Community "Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs." 10973_ASPIRE_win08.indb 16 12/12/07 3:28:24 PM